A Review of the Role of Green Tea in Antiphotoaging, green tea recent articles Stress Resistance, Neuroprotection, and Autophagy

According to the European Food Safety Authority , 126 mg of catechins are present per 100 mL of green tea. However, according to the Food and Drug Administration , 71 mg of epigallocatechin gallate will be present per 100 mL of green tea. In the case of black tea, 200 mg of flavonoids are present per 100 mL .
Twenty Chinese women were volunteers in analyzing the effect of varying concentrations of green tea extract in protecting skin from UV induced photoaging through topical application . Along with the levels of erythema, the thickness of stratum corneum and epidermis, as well as the level of matrix metalloproteases, were measured by using microscopic and immunohistochemical analysis. On Day 1, a 3% topical application showed less erythema, whereas 5% showed damage along with the vehicle control and control with no topical application, which also showed post inflammatory hyperpigmentation. The sample using a 3% topical application showed mild pigmentation, whereas the other samples showed moderate pigmentation. Between 2 and 3% of topical applications showed a controlled level of thickening of the stratum corneum and epidermis when compared to other samples. A significant reduction of matrix metalloproteases was observed in applications ranging from 2 to 4%. Overall, this study suggests that an optimum concentration of green tea extract can protect the skin from UV radiation-induced damage .
Ascorbic acid is considered to be one of the most powerful, water-soluble, natural antioxidants, with very little toxins associated with it and which is present in many dietary foods or plants . It has been shown to have a positive effect against the superoxide radical anion, H 2 O 2 , the hydroxyl radical, and the singlet oxygen radical. It can also neutralize RNS in aqueous solutions. Ascorbic acid is abundantly found in citrus fruits, kiwi, cherries, melons, and tomatoes, as well as leafy vegetables like broccoli, cauliflower, and cabbage. Tocopherols are the most widely used antioxidants, and are mainly present in nuts, seeds, and vegetable oils .
A Review of the Role of Green Tea in Antiphotoaging, green tea recent articles Stress Resistance, Neuroprotection, and Autophagy
A Review of the Role of Green Tea in Antiphotoaging, green tea recent articles Stress Resistance, Neuroprotection, and Autophagy
Human brains consume approximately 20% of the oxygen inhaled, but its antioxidant activity is less than that of other organs . This increases the possibility of an increased level of ROS inside the brain, which can have serious health effects such as mitochondrial dysfunction and apoptosis that could lead to neurodegenerative diseases like Alzheimer’s and Parkinson’s disease .
The depletion of the ozone layer allows easier penetration of UV radiation into the earth, which subsequently increases the level of skin cancer among people. Sunscreens are widely used to protect skin from UV. It can be used to scatter, reflect, or absorb radiation. However, compounds like titanium dioxide and zinc oxide in commercial sunscreen creams may create an opaque layer over the skin, which can damage the proper functioning and nourishment of the skin cells . Natural products with antioxidant activity, which could enhance the endogenous capacity of the skin and help neutralize ROS , should be considered as an effective alternative for these chemical agents.
The present manuscript reviews the reported anti-photoaging, stress resistance, neuroprotection, and autophagy properties of green tea in a narrative way. The references for the present review were collected from a PubMed search with green tea, photoaging, stress resistance, neuroprotection, and autophagy as keywords, and those publications that fit into the present review were segregated without considering a year limit.
In aerobic conditions, the transfer of electrons occurs between atoms, wherein oxygen is the ultimate electron acceptor which produces ATP . However, the transfer of uncoupled electrons results in the generation of free radicals such as reactive oxygen species and reactive nitrogen species . ROS are produced regularly inside the body, specifically in the mitochondria, during respiration and other immune-related functions . They can act as a mobile signaling messenger inside the host. The overall cellular health is dependent on the level of ROS inside the host . The endoplasmic reticulum transmembrane protein mediates homeostasis by initializing the unfolded protein response pathway. However, during the accumulation of ROS, IRE-1 is unable to initialize this mechanism. Rather, the Nrf2 pathway is activated, which could initiate stress resistance, as observed in model organism Caenorhabditis elegans and in cells . However, too much ROS and RNS may result in damage to cellular components such as nucleic acids , proteins , carbohydrates, lipids , and other molecules, which could lead to mutations and eventually to cancer and other age-related diseases . Additionally, ROS may accumulate inside the body from external sources like smoking, and exposure to harmful pesticides and some other pollutants . These ROS molecules induce oxidative stress, which can have an impact on many biological processes including apoptosis and autophagy, as they can harm different biomolecules and organelles and lead to an inflammatory response in the host. The host cells have a network of antioxidant enzymes which can neutralize an excess amount of ROS inside the body. Superoxide dismutase , catalase , the glutathione peroxidases , and thioredoxin are some of the endogenous antioxidants present in the host to neutralize excess ROS and maintain equilibrium .
2 Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand; [email protected] ; [email protected]
In another randomized double-blind study, topical application of green tea to the skin was undertaken before and after UV exposure. After 72 h of exposure, a 57% of reduction of epidermal Langerhans cells was observed in the vehicle control, whereas green tea treated cells showed a 35% reduction when compared to unexposed cells. DNA damage was also analyzed, and the vehicle control showed a significant increase when compared to the unexposed control. However, volunteers who undertook topical green tea application did not show any significant changes in damage to DNA when compared to the unexposed control .
Fresh tea leaves have an average of 30% of catechins by dry weight, which constitutes the flavonol group of polyphenols. Apart from this, tea also contains chlorogenic acid and coumarylquinic acid, along with theogallin and theanine , which are unique to tea. Caffeine is also present in tea, along with trace amounts of other common methylxanthines, theobromine, and theophylline. Tea can also accumulate aluminum and manganese. During the manufacture of black tea, initially the leaf structure is disrupted, which allows the aerobic oxidation of catechins. This is mediated by polyphenol oxidase, which is present in tea leaves along with other enzymes. A series of compounds like bisflavanols, theaflavins, epitheaflavic acids, and thearubigensare produced by the condensation process of various quinines. These are known to impart the characteristic taste and color properties of black tea .
EGCG was found to suppress the neurotoxicity induced by Aβ, as it could activate the glycogen synthase kinase-3β , along with inhibiting c-Abl/FE65—the cytoplasmic nonreceptor tyrosine kinase which is involved in the development of the nervous system and nuclear translocation . In another study, EGCG was observed to suppress the expression of TNFα, IL-1β, IL-6, and inducible nitric oxide synthase , restoring the levels of intracellular antioxidants against free radical-induced pro-inflammatory effects in microglia, nuclear erythroid-2 related factor 2 , and heme oxygenase-1 . Additionally, EGCG suppressed Aβ-induced cytotoxicity by reducing ROS-mediated NF-κB activation and mitogen-activated protein kinase signaling, including c-Jun N-terminal kinase and p38 signaling .
M.I.P., B.S.S., C.C., and T.T. contributed to conception and design, acquisition, manuscript preparation, and critical revision of the manuscript. All the authors equally contributed and are in agreement with the content of the manuscript.
In C.elegans , the lifespan extension is mediated by the DAF-16 pathway, also known as the insulin/IGF-1 pathway. The mutation or downregulation of daf-2 or age-1 extends the lifespan of the worms, aided by the upregulation and increased nuclear localization of daf-16 , which could be mediated by HSF-1 and SKN-1. The green tea extract also causes an increase of lifespan in C. elegans , which is dependent on the DAF-16 pathway . *indicates mutation.
EGCG was also observed to increase the specificity and sensitivity of radiation in targeting cancer cells through autophagy, and the Nrf2 mechanism in colorectal cancer cells . Doxorubicin, the chemotherapeutic drug for treating osteosarcoma cancer cells, was observed to have synergistic effects when combined with EGCG, thereby aiding in improving the clinical efficacy of antitumor drugs and promoting their further development . Prevention and treatment of hepatocellular carcinoma in HepG2 cells were initiated by EGCG by regulating α-fetal protein secretion, thereby modulating autophagy .
However, we strongly believe that findings from these experimental models cannot be directly extrapolated into humans, because of the complex network of interlinked physiological processes that natural compounds can act upon. Humans share many evolutionarily conserved mechanisms with different species which could have been inherited during evolution. However, due to our complex physiological, social and cultural development, which cannot be observed in many of the model organisms , the models are not a perfect match. Additionally, the absorption of the flavonoids under study will be lower in the circulatory systems of these models, as they will be metabolized differently by the microbiota inside the intestine, which is unique . For example, resveratrol—which is well known to extend the lifespan in many models like C. elegans —Cannot reproduce the same effect in higher models like mice. The difference in the dose, gender, genetic background, diet composition, and so forth could have a potential role in regulating changes in these effects . Similarly, in the case of green tea extract, there are studies in different model organisms about its potential to extend lifespan and healthspan, which we have discussed in this review. Future research should focus on humans, to identify if the same effects can be reproduced. Clinical trials should be undertaken to identify the optimum dose of green tea in humans to achieve the maximum health benefits. This could be the next potential leap in the field of healthspan research.
Tea polyphenols were found to directly scavenge ROS and RNS, inhibit the activity of nitric oxide synthase, xanthine oxidase, cyclooxygenases, and lipoxygenases, along with nuclear factor-кB and activator protein-1, and induce antioxidant enzymes such as glutathione S-transferases and superoxide dismutases to bind and chelate excess metals such as iron and copper, in vitro . EGCG can modulate the accumulation of proteins like Huntingtin, β-amyloid, and α-synuclein, and thereby enhance the clearance of three AD-relevant phosphorylated tau epitopes in primary neurons . Green tea and fractions of green tea aroma were found to delay Aβ-induced paralysis, which led to suppression of Alzheimer’s in transgenic nematode strains.
However, proper care should be taken to avoid excess use of antioxidants, as it could be harmful. Vitamins A, E, and C and β-carotene in high doses have not been shown to extend health benefits, but rather lead to hypervitaminosis and intoxication . Case studies have been reported in the United States regarding toxic reactions after consuming vitamin A at a dose of approximately 100,000 IU/day. Similar results have also been reported for vitamin E and ascorbic acid .
A green tea extract was applied to the crows’ feet of 42 Korean females twice a day for eight consecutive days. It was observed that the green tea extract displayed free radical scavenging activity and antiwrinkle effects in the host . In another placebo-controlled blind study, 56 randomly chosen women aged 25 to 75 were given oral supplements of 250 mg green tea polyphenols for two years, and were observed to have significant improvement in their facial skin and in controlling erythema .
This research received no external funding.
Cancer cells use autophagy to protect themselves from harsh conditions and increase their survival during chemotherapy and ionizing radiation . In a recent study, EGCG was combined with a low strength pulsed electric field and a low energy ultrasound as a novel method for cancer treatment. After 72 h of treatment, it was observed that this combination could achieve 20% alteration in the viability of human pancreatic cancer when compared to the control. Additionally, it could increase the level of intracellular ROS and inhibited Akt phosphorylation. Altogether, this combinatorial treatment induced autophagy as it switched from cytoprotective to cytotoxic, thereby causing cancer cell death with apoptosis .
Excessive use of green tea can impart negative results, as these polyphenols inside the system will make them unstable, leading to autoxidative reactions and resulting in ROS production and the increase of other DNA damaging factors . The overactivation of Nrf-2 was found to induce cardiovascular conditions and cancer . Higher concentrations of EGCG inhibited autophagy, leading to apoptosis in macrophagecelllines and cancer cells . Another study has proven the sensitivity of cancer cells towards the prooxidant activity of green tea . These reports suggest that only optimum doses of green tea alone may be beneficial, and if taken in excess, it could have a negative effect on humans.
Tea is one of the most widely consumed beverages worldwide, and is the second-most consumed drink after water . It is produced from the leaves, buds, or delicate stems of the plants of the genus Camellia. The most widely used plant species for tea is Camellia sinensis Kuntze. Inhabitants of Europe, mainly Great Britain, are the largest consumers of tea per day . However, on average across the world population, a person consumes ~120 mL of tea per day . Tea is available in three major forms—Green tea, oolong tea, and black tea—depending on the level of antioxidants present and the degree of fermentation . According to the available literature, tea was first consumed as a drink or medicine by the Chinese population around 2737 BC . Presently, tea is consumed in almost all countries worldwide, and China, India, and Kenya are the major producers of tea, even though it is cultivated on six continents . Approximately three billion kilograms of tea is produced and consumed worldwide per year .
Dietary supplementation of green tea to fruit flies throughout their life resulted in a longer lifespan, along with reduced total body iron levels. This suggests an interplay between lifespan mediation and the iron-binding properties of green tea extract . However, it could reduce the fertility of male Drosophila , which could be dependent on the mitochondrial iron transporter, mitoferrin . EGCG has been found to extend the lifespan in Drosophila . Additionally, consumption of tea was observed to reduce the activity of toxic metals like cadmium and lead inside the body of mammalian models. These metals may reduce the activity of endogenous antioxidants. However, intake of exogenous green tea could reduce the activity of these metals and protect the host from metal stress .
Additionally, ROS is required in certain amounts inside all living systems. An excess level of ROS will lead to damage to different cellular components, like nucleic acids and proteins, which can lead to many age-related diseases. In humans, exercise activates AMP kinase, which stimulates blood glucose uptake. Antioxidants prevent this stimulation of glucose uptake, suggesting the possible role of ROS . Similarly, in the case of C. elegans , low levels of juglone—Which is known to generate ROS—Extends the lifespan .
ROS can also interfere in the reproductive ability of organisms by inducing decreased sperm motility and compromised vitality in males, whereas in females it can inhibit oocyte maturation. EGCG was observed to reduce the level of ROS and impart antioxidant activity . Tea extract, when combined with sperm storage media, dose-dependently increased sperm viability . EGCG in the culture media of bovines showed improved rates of pregnancy and blastocyst development . Tea polyphenols can increase the level of glutathione peroxidase and reductase, glutathione S-transferase, catalase, quinone reductase, and superoxide dismutase in different rodents , along with inhibiting DNA oxidative damage , which ultimately acts as the stress response mechanism .
The polyphenols present in green tea have good ROS scavenging activity, which makes it a potential candidate in antiphotoaging therapy . In a recent study, tea polyphenols were fed to mice which had undergone a UV mediated photoaging process. A significant increase in hydroxyproline content was observed in vitro, and catalase activity increased along with decreased protein carbonyl content .An aqueous extract of green tea was found to improve the skin of mice affected by photoaging. It was found to increase the level of collagen and elastin fibers and reduced the expression of collagen-degrading MMP-3 enzymes, thereby showing potential antiwrinkle effects .
Effects of green tea supplementation on photoaging, stress resistance, neuroprotection, and associated health complications: Results of in vivostudies.
Skin is the largest organ of the human body, and creates an effective external barrier against the detrimental effects of environmental and xenobiotic agents, such as smoking, contaminants in the air and water, excessive oils and fats, drugs, and heavy metals, which induce extrinsic aging . It is the first line of defense to protect the internal organs of the body and maintains homeostasis through diverse mechanisms . Skin aging is a complex process mediated by the intrinsic process of senescence, and extrinsic damage induced by external factors like chronic exposure to UV irradiation—a process known as photoaging —Which can lead to erythema, edema, sunburn, hyperplasia, premature aging, and the development of non-melanoma and melanoma skin cancers . UV can cause skin damage either directly, through absorption of energy by biomolecules, or indirectly, by increased production of ROS .
Antiphotoaging property of green tea phytochemicals. Polyphenols present in green tea positively alter the physiochemical features of the system, and confer protection from accelerated photoaging .
Tea was considered an effective medicine for treating different ailments in ancient Asian folk medicine . It is known for its abundance of antioxidants. Presently, numerous research findings suggest the role of tea in mediating the proper functioning of the cardiovascular system, reduction of body mass, and even decreasing the risk of cancer and neurodegenerative diseases . Tea is considered a functional food since it can impart many physiological benefits apart from its nutritional contents . Its antioxidant property makes it a predominant regulator in mediating free radicals, which is of significant use in healthcare.
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Herbs like green tea can be effectively used in different antiaging products, which could safely mitigate and reverse photoaging signs and symptoms. The novel concept of treating photoaging and preventing its progression by using natural products is now on the rise . Mediterranean and Asian diets comprised of different polyphenols, including green tea, are now being widely accepted because of their enormous health benefits, including protective effects against cardiovascular and neurodegenerative diseases . However, there is still no clear data on the optimum dose of natural compounds to impart health benefits to humans. Different model organisms, such as C . elegans , Drosophila , and mice, are used for high throughput screening of different polyphenols for their effects in mediating lifespan and other health benefits, as these models can act as a whole organism, which enables researchers to understand the different effects exerted by these compounds during the overall lifespan of the organism .
M.I.P. wishes to thank the Ratchadaphiseksomphot Endowment Fund for Postdoctoral Fellowship and Chulalongkorn University, Thailand, for the support. B.S.S. and C.C. gratefully acknowledge the Chiang Mai University grant , Chiang Mai University, Thailand for the support.
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Effects of green tea supplementation on photoaging, stress resistance, neuroprotection, and associated health complications: outcomes of clinical trials.
The authors declare no conflicts of interest.
Green tea polyphenols were found to inhibit chronic UV irradiation-induced protein oxidation in mouse skin tissue . EGCG, apart from mediating the lifespan, was also observed to maintain equilibrium in redox reactions during altered insulin regulation . It can also activate the nuclear erythroid-2 like factor-2 transcription factor, which can reduce oxidative stress and other cardiovascular conditions . Recently, EGCG was observed to improve the memory function by mediating RNS levels . Onishi observed that the intake of green tea extract in mice with a high fat diet could reduce muscle atrophy, along with insulin resistance . Green tea powder was observed to induce the expression of different antioxidant enzymes, such as SOD, GSH, and peroxidase, in rats under oxidative stress . In hamsters, consumption of green tea inhibited carcinogen induced-lipid peroxidation and oxidative DNA damage in the pancreas .
Some case reports have also indicated that excessive intake of tea extracts induces liver toxicity , which is probably due to the prooxidant property of tea polyphenols . It is proposed that low and moderate doses of tea polyphenols produce lower levels of ROS, which activates Nrf2 to attenuate oxidative stress, whilst high dose of tea polyphenols produce high levels of ROS and induce toxicity . In this regard, optimum doses of green tea must be consumed, which can provide numerous health benefits to mankind.
Autophagy is an internal process that aids in the lysosomal degradation and removal of old and unwanted cellular molecules, including proteins, ribosomes, lipid droplets, and other organelles, thereby maintaining cellular homeostasis and survival under metabolic stress . In this manner, autophagy protects the overall health of the host, especially in conditions like diabetic cardiomyopathy and cancer . In mammalian cells, PI3 kinase forms a complex with BECLIN-1 and thereby activates autophagy . Inhibition of the mammalian target of rapamycin increases autophagy, which makes rapamycin an autophagy inducer . Additionally, the mitogen-activated protein kinase pathway can also activate autophagy . Activation of AD could also provide neuroprotective effects, as impaired autophagy may lead to the accumulation of Aβ in the host . Many bioactive polyphenols, like curcumin and isoflavones , can activate autophagy. Optimum concentrations of EGCG were able to induce autophagy, anti-inflammatory action , degrade lipid droplets in endothelial cells , and facilitate degradation of endotoxins leading to anti-inflammatory actions . Growing evidence suggests that the activation of autophagy by different polyphenols should contribute to their neuroprotective effects . Tea polyphenols were observed to activate autophagy through various different mechanisms, including the mammalian target of the rapamycin pathway during endoplasmic reticulum stress in HEK293T cells, along with AMP-activated protein kinase . EGCG treatment can induce autophagy, as it diminishes the effect of negative regulators of autophagy such as GADD34, which controls apoptosis. In other words, green tea recent articles EGCG was able to extend autophagy, thereby delaying apoptosis mediated cell death and eventually extending cell viability .
Interestingly, higher concentrations of EGCG, for example, 100μM in macrophage cell lines, can inhibit autophagy leading to apoptosis . On the whole, the autophagy properties of green tea depend upon the dosage used, level of stress, and the cells involved . Until now there has not been a clear idea of the mechanism of action initiated by green tea extract to mediate autophagy .
Calorie restriction is a major mechanism for stimulating autophagy, which in turn can lead to an increase in lifespan and also depends on the removal of damaged cellular components accumulated during cellular aging. Sirtuins and AMP-activated protein kinase are the key players involved in mediating this mechanism . The orthologs of these genes in C. elegans are sir-2.1 and aak-2 . Previous studies have suggested that black tea and green tea can increase the lifespan of nematodes through a sir-2.1 -dependent mechanism. In hepatic cells, EGCG was observed to activate AMPK, thereby activating autophagy . Tea polyphenols were able to activate autophagy in high fat fed rats, along with inhibiting the level of high blood glucose-induced autophagy .
Any shift in the equilibrium, which may happen due to a reduction of antioxidants inside the system or due to an increase in ROS as a result of immune-related processes, will lead to oxidative stress . Prolonged stress and aging may play a major role in reducing the efficiency of endogenous antioxidants against oxidative stress . ROS promote peroxidation of the lipids in the cell membranes, along with altering the structure and function of different enzymes and promoting carbohydrate oxidation . Inside the brain, this could lead to neurological, age-associated diseases like Parkinson’s disease and Alzheimer’s disease . In this regard, exogenous antioxidants may be better at modulating excess levels of ROS inside a host. Identification of natural sources of antioxidants, mainly of plant origin, may have several advantages over focusing on chemical compounds. Natural sources can be taken as food additives, which could hinder the chain reactions of oxidation, thereby inhibiting the oxidation process .
Tea is one of the most widely consumed beverages worldwide, and is available in various forms. Green tea is richer in antioxidants compared to other forms of tea. Tea is composed of polyphenols, caffeine, minerals, and trace amounts of vitamins, amino acids, and carbohydrates. The composition of the tea varies depending on the fermentation process employed to produce it. The phytochemicals present in green tea are known to stimulate the central nervous system and maintain overall health in humans. Skin aging is a complex process mediated by intrinsic factors such as senescence, along with extrinsic damage induced by external factors such as chronic exposure to ultraviolet irradiation—A process known as photoaging—Which can lead to erythema, edema, sunburn, hyperplasia, premature aging, and the development of non-melanoma and melanoma skin cancers. UV can cause skin damage either directly, through absorption of energy by biomolecules, or indirectly, by increased production of reactive oxygen species and reactive nitrogen species . Green tea phytochemicals are a potent source of exogenous antioxidant candidates that could nullify excess endogenous ROS and RNS inside the body, and thereby diminish the impact of photoaging. Several in vivo and in vitro studies suggest that green tea supplementation increases the collagen and elastin fiber content, and suppresses collagen degrading enzyme MMP-3 production in the skin, conferring an anti-wrinkle effect. The precise mechanism behind the anti-photoaging effect of green tea has not been explored yet. Studies using the worm model have suggested that green tea mediated lifespan extension depends on the DAF-16 pathway. Apart from this, green tea has been reported to have stress resistance and neuroprotective properties. Its ROS scavenging activity makes it a potent stress mediator, as it can also regulate the stress induced by metal ions. It is known that tea polyphenols can induce the expression of different antioxidant enzymes and hinder the DNA oxidative damage. Growing evidence suggests that green tea can also be used as a potential agent to mediate neurodegenerative diseases, including Alzheimer’s disease. EGCG, an abundant catechin in tea, was found to suppress the neurotoxicity induced by Aβ as it activates glycogen synthase kinase-3β , along with inhibiting c-Abl/FE65—the cytoplasmic nonreceptor tyrosine kinase which is involved in the development of the nervous system and in nuclear translocation. Additionally, green tea polyphenols induce autophagy, thereby revitalizing the overall health of the organism consuming it. Green tea was able to activate autophagy in HL-60 xenographs by increasing the activity of PI3 kinase and BECLIN-1. This manuscript describes the reported anti-photoaging, stress resistance, and neuroprotective and autophagy properties of one of the most widely known functional foods—green tea.
The optimum consumption of green tea with antioxidants delivers many health benefits, such as preventing cancer and cardiovascular ailments , regulating cholesterol , mediating weight loss , regulating aging, reducing the inflammatory response, and controlling neurodegenerative diseases . Green tea polyphenols have also been observed to exhibit potential effects in inhibiting tooth decay and reducing blood pressure, along with antibacterial, antioxidant, and antitumor properties . EGCG has been observed to have a role in cancer chemoprevention . After consumption, catechins of green tea undergo phase II metabolism, and have been shown to be present in conjugated and unconjugated forms in plasma . Even though it is not widely accepted, many researchers believe that green tea can exert positive effects on diabetes . Green tea reduces the level of oxidative stress and inhibits glucose uptake via the insulin pathway .
Green tea mainly consists of polyphenols , amino acids , theanine, proanthocyanidins, and caffeine . Among the different polyphenols, catechins and flavonols are the major constituents. Catechin , epicatechin , gallocatechin , epigallocatechin , epicatechin gallate , epigallocatechin gallate , and gallocatechin gallate are the major catechins present in green tea . Among these, EGCG, ECG, and EGC constitute 80% of the total catechins . The quality of green tea mainly depends on the time of harvesting and leaf age. The amount of theanine, theobromine, caffeine, catechin, and GCG decreased in later harvests. However, the amount of EC, EGCG, and EGC increased in the same conditions . Similarly, young leaves were found to have higher amounts of caffeine, EGCG, ECG, and other catechins when compared to older leaves . This is thought to occur due to the withering process . EGCG is the most abundant catechin, representing 50–80% of the total catechins in green tea. It is also considered to be the major contributor to the various health benefits of green tea .
ROS is essential for normal cellular metabolism and signaling. However, an alteration in the level of ROS can lead to oxidative stress, which damages cells and thereby the whole organism. Exposure to antioxidants during oxidative stress aids in the protection of the host by radical scavenging activity, or by other indirect antioxidant mechanisms . An abundance of antioxidants allows green tea to impart stress resistance under these different physiological conditions . One of the important functions of green tea polyphenols is their vascular protective effect by anti-oxidative, anti-hypertensive, anti-inflammatory, anti-proliferative, anti-thrombogenic, and lipid-lowering activity. They can scavenge free radicals, chelate redox active transition metal ions and inhibit redox active transcription factors, alter enzymes involved in lipid biosynthesis, and reduce intestinal lipid absorption. They can prevent vascular inflammation, thereby preventing atherosclerotic lesions, inhibiting proliferation of vascular smooth muscle cells, and suppressing platelet adhesion . These properties help green tea to reduce the stress level in the body, and thereby provide protection against cardiovascular ailments.
A cross-sectional study conducted in China with 2015 subjects aged over 65 years suggested that consumption of tea reduced the prevalence of Alzheimer’s disease and cognitive impairment . Another study done with 215 subjects suggested that regular consumption of tea could reduce the level of Parkinson’s disease .
Topical application of epigallocatechin gallate was found to prevent skin tumor incidence and multiplicity in wild type mice. However, this was not possible in IL-12 knockout mice. Additionally, EGCG could also reduce the number of cells affected by sunburn in wild type mice alone. This suggested that EGCG can act against UV induced tumor formation, along with reducing DNA damage and sunburn via an IL-12 dependent mechanism . Green tea was applied topically or given as feed to different sets of mice before exposing them to UV radiation. In both the conditions, there was a significant reduction in the level of tumors when compared to the control . In another study, mice treated with 2% EGCG showed a significant decrease in the number of sunburn cells in rats after UV exposure .Feeding of green tea seed extract was found to reduce the signs of UV induced photoaging, such as wrinkle formation, and increase the synthesis of collagen in mice .
A cascade of changes happens in the skin when exposed to UV radiation, leading to photoaging. Skin photoaging largely depends on the presence of melanin in the cells, which acts as the first level of defense against UV radiation. However, excess production of melanin can lead to damage like melasma, freckles, and senile lentigo. During exposure to UV radiation, tyrosinase is activated, which enhances the production of melanin in the cells . Subsequently, UV will degrade the collagen and elastin fibers in the skin, leading to wrinkle formation along with increasing levels of ROS and matrix metalloproteases, which will damage the collagen fibers and thereby collectively induce photoaging. Parallel to this, UV exposure induces immunosuppression in skin cells, thereby blocking the normal function of protection from infection and removal of damaged cells. Immunosuppression is mediated by different mechanisms, such as suppression of contact hypersensitivity , infiltration of leukocytes, DNA damage, and attenuation of antigen-presenting capacity .
1 Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand;
The Insulin/IGF-1 mediated pathway, also called the IIS pathway, is known as the DAF-16 mediated pathway in C. elegans and is orthologous to the mammalian FOXO regulatory pathway. Mutations in daf-2 , which is orthologous to IGF-1 receptors, can double the lifespan of a model nematode. Additionally, mutations in age-1 , the downstream phosphatidylinositol 3-kinase K)/AKT/PDK kinase, can also extend the lifespan of the nematode . The changes in lifespan are mediated by daf-16 , orthologous to the FOXO transcription factor, which when mutated will reduce the lifespan. The heat shock transcription factor HSF-1 and SKN-1 , a Nrf-like xenobiotic-response factor, will help to mediate lifespan regulation.
Atrazine is a widely used herbicide which also has neurotoxic effects and can induce cell death in dopaminergic neurons, which could be overcome by autophagy. Green tea polyphenols, along with isoflavones, resveratrol, quercetin, and curcumin, were observed to activate autophagy in SH-SY5Y cells, which was suppressed by atrazine . Green tea was able to activate autophagy in HL-60 xenographs by increasing the activity of PI3 kinase and BECLIN-1 . EGCG can also protect the primary neuronal cells from prion diseases activating autophagy by inducing sirtuins . It can also inhibit the growth of breast cancer cells in vitro and in vivo by altering autophagy, as it increases the formation of autophagosomes and autolysosomes . Similarly, brain cancer cells can also use EGCG to induce autophagy . In microglial cells, green tea catechins were observed to prevent hypoxia-induced oxidative stress and cell death by inducing autophagy .
Many of the pathways that mediate aging were first discovered in small, short-lived organisms like worms and flies, then were further extrapolated to humans. Under normal conditions, the genes involved in aging pathways helps to mediate growth, development, and reproduction. However, during stress conditions, the transcription factor genes will alter their regulation to activate stress resistance mechanisms, and thereby extend the lifespan .
AD mice models fed with 2–6 mg/kg of EGCG for four weeks showed a significant reduction in the accumulation of Aβ . The transgenic mouse model, which expresses amyloid precursor proteins, was orally fed with 50 mg/kg of EGCG from two months old upto six months old, and showed a significant reduction in the levels of Aβ. Additionally, green tea polyphenols and epicatechin were able to suppress tau proteins and improve cognitive function, along with reducing accumulation of Aβ .EGCG, when injected intraperitoneally or administered orally , could decrease the levels of Aβ and plaque formation in a transgenic mouse model of “Swedish”mutant APP . Oral consumption of EGCG in transgenic mice for three months showed 60% and 52% reduction of Aβ deposits in the frontal cortex and hippocampus, respectively. EGCG can be considered a therapeutic agent for neuroinflammation-associated AD, as it was able to prevent memory impairment induced by lipopolysaccharide and apoptotic neuronal cell death in mice. Additionally, it can prevent the activation of astrocytes and increase cytokine expression .
1 Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand;
2 Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand; [email protected] ; [email protected]
Green tea catechins, in a dose-dependent manner, were found to protect human osteoblasts from smoke-induced injury by the reduction of free radical formation . They can also reduce the levels of lipid peroxides and protein carbonyl content . Green tea extract, when analyzed for its effect on Caco2 cells, was found to decrease the level of ROS. Additionally, after using a pretreatment of green tea extract for 20 h before exposure to oxidative stress, cell viability was increased and the production of free radicals was reduced when compared to controls . Interestingly, consumption of green tea in chronic smokers was associated with a significant reduction of smoking-induced micronuclei in the white blood cells . The results suggest that green tea may promote a healthy lifespan in humans also.
Flavonoids are the most common antioxidant components found in plant sources. Flavonoids are the major antioxidants in the diet, and are known to protect against cardiovascular diseases by reducing the level of oxidation of low-density lipoproteins. Apigenin, chrysin, luteolin, datiscetin, quercetin, myricetin, morin, and kaempferol are some of the most commonly found flavonoids . Additionally, phenolic acids are also known to counteract against oxidative damage mediated diseases like coronary heart disease, stroke, and cancers . Carotenoids, largely found as food micronutrients in the human diet , have significant antioxidant properties in plants and humans. They can scavenge singlet molecular oxygen and peroxyl radicals . These antioxidants from natural sources are widely accepted as useful, mainly because of their wide range of activities against almost all kinds of oxidants, along with very limited side effects . Green tea extract, specifically, can also have significant effects against ROS and RNS , which will be discussed in detail in the later sections.

Tea mainly consists of polyphenols, caffeine, minerals, and trace amounts of vitamins, amino acids, and carbohydrates. The type of polyphenols present in tea will vary depending upon the level of fermentation it has undergone. Green tea mainly consists of catechins, whereas black tea mainly contains tannins . Notably, green tea is considered the most predominant source of catechins among all dietary sources, ahead of chocolate, red grapes, wine, and apples . The caffeine in tea leaves ranges between 2 and 5%, depending on the age of the leaf, wherein younger leaves will have a higher concentration . Tea is known to stimulate the central nervous system and cardiac function in humans . Different minerals, like fluoride, manganese, chromium, selenium, calcium, magnesium, and zinc, are present in tea leaves in different concentrations depending upon the fermentation process, age, and size of tea leaves .
Green tea was observed to reduce memory impairments and prevent oxidative stress and damage in the hippocampus in a rat model for Alzheimer’s disease, with better effect than red and black tea. This could be attributed to the increased level of EGCG in green tea . Tea polyphenols, when administered orally, could reduce motor impairments and dopaminergic neuronal injury, and attenuate dopamine depletion and dopaminergic neurons in monkeys with Parkinson’s disease, along with improving the motor functions of the brain . Tea polyphenols rescued and restored the impaired movement activity induced by paraquat in Drosophila models of Parkinson’s disease .
Theanine, an ingredient in green tea, has been observed to promote resistance against paraquat, thereby promoting longevity in C. elegans . Tea also reduced the lipid droplets and fat accumulation in C. elegans by downregulating the expression of vitellogenin family genes .The optimum levels of EGCG were found to extend the lifespan in C. elegans in the AMPK/SIR-2.1/DAF-16-mediated pathway during stress. EGCG was observed to activate AMPK, which in turn activates NAD followed by SIR-2.1 . Upon activation, SIR-2.1 can activate the DAF-16 transcription factor, which eventually activates many antioxidant factors . Chlorogenic acid is also able to extend the lifespan and delay the age-related decline in body movements of C. elegans , which is dependent on the IIS pathway .
Consumption of four cups of green tea per day for four months reduced urinary 8-hydroxydeoxyguanosine levels by 31% in 143 smokers aged between 18 years to 79 years . Sixty males with high-grade prostate intraepithelial neoplasia, who were expected to get cancer within one year, were made to consume 600 mg of green tea extract per day in a double-blind clinical trial for one year. Only one tumor case was identified among the 30 subjects who consumed green tea catechins, against nine cases out of 30 who had taken the placebo .
In a recent study, human volunteers were made to consume green tea polyphenols in the form of capsules for a limited period, and it was observed that green tea catechins conjugate their metabolites in plasma, blister fluid, and skin biopsy samples . In another study, 18 individuals aged between 21 years and 71 years were asked to apply green tea extract and a placebo topically, before exposure to UV radiation. The biopsy analysis and level of erythema suggested that the green tea pretreatment showed a significant reduction in the number of cells with sunburn . Volunteers aged between 18 years and 50 years applied various concentrations of green tea extract, ranging from 0.25 to 10%, to their skin. The green tea polyphenols applied before UV exposure decreased sunburn cells by 66%, in which the lower dose of 0.5% showed positive activity and the 2.5% concentration provided excellent protection. In the second part of the study, the skin was treated with equal concentrations of 5% green tea polyphenols and its constituents EGCG, EC, and EGC. However, the whole extract was the most effective in protecting from erythema, sunburn, and DNA damage, suggesting that the combined activity of green tea polyphenols show maximum activity above that of individual ones .
The consumption of antioxidant-rich fruits and vegetables is known to reduce the impact of different age-related diseases, including coronary heart disease and cancer . Polyphenols are chemical compounds with one or more phenolic groups per molecule . They may inhibit ROS induced damage to DNA, proteins and lipids, and produce inflammatory cytokines along with activating several signal transduction pathways . Different types of polyphenols include flavonoids , and non-flavonoids , and they are richly present in fruits, vegetables, tea, and other natural sources . Humans consume various compounds with antioxidant properties in their diet, like vitamin C, tocopherols, carotenoids, and flavonoids. These may have structural and functional variations, but their combined action helps to reduce the level of ROS .
Aging can be defined as the progressive loss of the cells, tissues, and organs of an individual across the lifespan . Periodic and continuous exposure to ultraviolet radiation will induce such changes, predominantly in the skin of an individual, which could be characterized by burning, tanning, loosening of the collagen and elastin fibers, and reduced integrity of the skin, which are collectively known as photoaging . Sunscreens can be applied which either absorb or reflect UV radiation, thereby protecting the skin . However, continuous application of sunscreens could have a negative effect on certain people . Individuals with sensitive skin may still be affected by UV radiation even when using sunscreen, since sunscreen does not give 100% protection from UV radiation due to not addressing heat accumulation. Additionally, several chemical compounds are added in sunscreens to induce broad-spectrum activity, and these can have a negative effect on sensitive skin . In this regard, compounds derived from natural sources with the desired properties, which could achieve similar benefits when compared to using synthetic compounds, are of significant interest. Green tea is one such product, and is widely known and used by people all over the world for its proposed benefits.
During UV-A-induced photoaging, the DAF-16 mediated pathway was found to be regulated, wherein qPCR analysis showed the downregulation of daf-16 and the upregulation of daf-2 , suggesting the involvement of the pathway . Further analysis of green tea extract in wild type nematodes also showed DAF-16 dependent regulation , which suggests that green tea can extend the lifespan in a model nematode exposed to UV-A . These findings could shed light on the mode of action elicited by green tea extract inside the host during photoaging.
Tea is one of the most popular antioxidants, and the most widely consumed drink after water . Green tea, oolong tea, and black tea are the three major forms of tea, and are categorized based on the level of antioxidants present and the degree of fermentation . Tea leaves are steamed at a high temperature after harvesting to inactivate the polyphenol oxidizing enzymes, which protects the majority of vitamins present in the tea . Thus, green tea possesses high levels of antioxidants and is used for its antiaging and neuroprotective effects , is lipton green tea helps weight loss

Tea and Health Studies in Humans tea articles

Tea, the most popular beverage consumed by two-thirds of the world’s population is made from the processed leaf of Camellia sinensis . Tea types, based on processing or harvested leaf development are black , green and oolong . These major tea types differ in how tea is produced and processed according to the different processes of drying and fermentation that determine its chemical composition. Green tea is produced by using young tea leaves and sold for consumption without fermentation after withering, steaming or pan firing, drying and grading. Pan firing is required to prevent the tea leaves from fermenting by the natural enzyme activities. Tea leaves are allowed to ferment for several hours before being either smoke fired, flame fired or steamed to make black tea. Oolong tea is produced by a partial oxidation of the leaf, intermediate between the process for green and black tea . Black tea is made by first exposing the tea leaves to air, causing them to oxidize. This oxidation process turns leaves into a deep brown color and during this process, the flavor is intensified. The leaves are then left as such or are heated, dried and crushed. Green tea is best studied for its health benefits, including cancer chemopreventive and chemotherapeutic effects , but emerging data is showing that black tea may possess similar health promoting attributes.
Various studies have reported beneficial effects of regular tea consumption against squamous cell carcinoma of the skin. In a population-based case-control study, adjusting for brewing time, the association between squamous cell carcinoma and hot black tea consumption suggests a significantly lower risk in consumers of hot tea compared to non-consumers. It was suggested that tea concentration, brewing time and beverage temperature have major influences on the potential protective effects of hot black tea in relation to squamous cell carcinoma of the skin . A population-based case-control study was conducted to evaluate the relationships between citrus peel use and black tea intake and squamous cell carcinoma of the skin. The independent and interactive effects of citrus peel and black tea in the development of squamous cell carcinoma were also assessed. Subjects who reported consumption of both hot black tea and citrus peel had a significant marked decrease risk of skin squamous cell carcinoma suggesting that both citrus peel use and strong black tea had protective effects in relation to squamous cell carcinoma of the skin . In a case-control study conducted in Italy, a significant inverse association between vitamin A intake and cutaneous malignant melanoma risk was found. There was no appreciable association of cutaneous malignant melanoma risk with selected food items, including fish, meat, vegetables, fruit, dairy products, whole meal bread, alcohol, coffee and tea drinking. Consumption of tea had a protective effect on cutaneous malignant melanoma risk . The effect of Polyphenon E ointment was investigated for efficacy and safety in the treatment of anogenital warts in immunocompetent men and women. Polyphenon E 15% or 10% ointment or matching vehicle was self-applied by 530 patients three times daily to all warts. The assessment of response and of adverse events was performed biweekly until complete clearance or for up to 16 weeks. Treatment with 10 and 15% Polyphenon E ointment showed complete clearance of all baseline and new anogenital warts in 51 and 53% of patients, respectively. It was also noted that 78% of all patients treated with either 10 or 15% Polyphenon E ointment showed wart clearance rates of 50% or better. There were only mild or moderate adverse effects as demonstrated by the safety profile of Polyphenon E ointments .
Tea is the most widely consumed beverage in the world, next only to water. There is often a misconception, essentially a marketing gimmick, that herbal tea is also tea. However, herbal tea is not made from the plant Camellia sinensis . Due to the popularity of tea, generally on a common trip to the grocery store, at least in US markets, one can find many types of tea preparations sold which are supplemented with various extracts of mango, strawberry, pomegranate, lemon, etc. These marketing strategies have boosted the sale of tea products to a non-tea drinking population. Similarly, tea constituents supplemented cosmetics and other products are sold to consumers.
Tea, next to water is the cheapest beverage humans consume. Drinking the beverage tea has been considered a health-promoting habit since ancient times. The modern medicinal research is providing a scientific basis for this belief. The evidence supporting the health benefits of tea drinking grows stronger with each new study that is published in the scientific literature. Tea plant Camellia sinensis has been cultivated for thousands of years and its leaves have been used for medicinal purposes. Tea is used as a popular beverage worldwide and its ingredients are now finding medicinal benefits. Encouraging data showing cancer-preventive effects of green tea from cell-culture, animal and human studies have emerged. Evidence is accumulating that black tea may have similar beneficial effects. Tea consumption has also been shown to be useful for prevention of many debilitating human diseases that include maintenance of cardiovascular and metabolic health. Various studies suggest that polyphenolic compounds present in green and black tea are associated with beneficial effects in prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease. In addition, anti-aging, antidiabetic and many other health beneficial effects associated with tea consumption are described. Evidence is accumulating that catechins and theaflavins, which are the main polyphenolic compounds of green and black tea, respectively, are responsible for most of the physiological effects of tea. This article describes the evidences from clinical and epidemiological studies in the prevention of chronic diseases like cancer and cardiovascular diseases and general health promotion associated with tea consumption.
Consumption of tea is increasingly being shown to be associated with enhanced cardiovascular and metabolic health. Green tea caused an increase in the activity of enzymes implicated in cellular protection against reactive oxygen species: superoxide dismutase in serum and the expression of catalase in the aorta. This action is combined with direct action on oxygen species by a decrease in the nitric oxide plasma concentration . Green tea catechins affect lipid metabolism by different pathways and prevent the appearance of atherosclerotic plaque. Its intake decreases the absorption of triglycerides and cholesterol and these findings are in accordance with the fact that it increases excretion of fat . In patients, who underwent coronary arteriography for the first time in China, green tea consumption was associated with a reduced risk of coronary artery disease in male patients, with an adjusted odds ratio of 0.62 compared with those who did not drink green tea. Compared to non-tea drinkers, the adjusted odds ratios were 1.09 in male patients consuming less than 125 g of dried green tea leaves per month, 0.36 for 125–249 g per month and 0.36 for more than or equal to 250 g per month. There were similar dose-response relationships for frequency, duration, concentration and starting age of green tea drinking in male patients, while no inverse association was found between green tea consumption and coronary artery disease in female patients . In a matched case-control analysis including 518 myocardial infarction, 333 hemorrhagic stroke, and 1927 ischemic stroke cases, the associations of these lifestyle factors with myocardial infarction and stroke were evaluated. Alcohol consumption was inversely associated with myocardial infarction, tea consumption was inversely associated with hemorrhagic and ischemic stroke and weight increase from age 20 to 40 was positively associated with myocardial infarction and stroke in a dose-response manner . In a case-control study in southern China, a significant decrease in ischemic stroke risk was observed for drinking at least one cup of tea weekly when compared with infrequent or non-drinkers, the risk reduction being largest by drinking one to 2 cups of green or oolong tea daily. Significant inverse dose-response relationships were also found for years of drinking and the amount of dried tea leaves brewed . In a meta-analysis, data from 9 studies involving 4378 strokes among 194,965 individuals was pooled. Individuals consuming more than or equal to 3 cups of tea/day had a 21% lower risk of stroke than those consuming less than 1 cup/day regardless of their country of origin with the proportion of heterogeneity not explained by chance alone being 23.8% .
Various studies have shown that tea may affect glucose metabolism and insulin signaling, causing interest in the health effects of tea consumption on diabetes. In a large cohort of U.S. middle-aged and older women from the Women’s Health Study, women who consumed more than or equal to 4 cups/day of tea had a 30% lower risk of developing type 2 diabetes than did those who did not consume tea . In a retrospective cohort study among Japanese adults, adults who consumed more than or equal to 6 cups/day of green tea lowered their risk of diabetes by 33%, while no association with diabetes risk was found for oolong or black teas. Consumption of more than or equal to 3 cups/day of coffee lowered the risk of diabetes by 42% and high caffeine intake was also associated with a 33% reduction in risk of diabetes. A lowered diabetes risk was also observed in women after green tea and caffeine consumption . The effects of continuous ingestion of a catechin-rich beverage in patients with type 2 diabetes who were not receiving insulin therapy in a double-blind controlled study were investigated. The patients were given green tea containing either 582.8 mg of catechins or 96.3 mg of catechins/day for 12 weeks. Waist circumference decreased in the catechin group than in the control group at 12 weeks. There was increase in insulin and the decrease in hemoglobin A levels in the catechin group than in the control group in patients treated with insulinotropic agent . The possible effects of different daily doses of black tea intake on certain oxidative stress, inflammatory and metabolic biomarkers in patients with type 2 diabetes mellitus. Patients were given 150, 300, 450 and 600 ml of black tea extract during the weeks 1, 2, 3 and 4, respectively, while the control group received 150 ml BTE throughout the intervention period. It was found that serum total antioxidant capacity was enhanced similarly in both test and control groups, but a suppressing effect on serum malondialdehyde was observed with daily intake of 2 cups of BTE. After ingesting 4 cups of BTE a day, there was decrease in the level of serum C-reactive protein and increase in the glutathione levels. It was concluded that regular consumption of BTE had anti-oxidative and anti-inflammatory effects in patients with type 2 diabetes mellitus .
This review article describes the major epidemiological and clinical studies on tea consumption and the risk of cancer at different organ sites in humans. We also present the evidences for the association of tea drinking and its effects on diabetes, arthritis and neurological system in humans.
Tea and Health Studies in Humans tea articles
Tea and Health Studies in Humans tea articles
Reported Effects of Tea on Skin, Prostate, Lung and Breast Cancer in Humans.
Few studies have reported the beneficial effects of tea against arthritic disease in humans. In a study in Britain, it was found that those who drank tea had greater bone mineral density than those who did not drink tea . Coffee, tea, and caffeine consumption were evaluated as risk factors for rheumatoid arthritis onset among older women in a prospective cohort study. Compared with those reporting no use, subjects drinking more than or equal to 4 cups/day of decaffeinated coffee were at increased risk of rheumatoid arthritis. In contrast, women consuming more than or equal to 3 cups/day of tea displayed a decreased risk of rheumatoid arthritis compared with women who never drank tea, while caffeinated coffee and daily caffeine intake were not associated with the development of rheumatoid arthritis. The associations of rheumatoid arthritis onset with the highest categories of decaffeinated coffee and tea consumption were stronger in women with seropositive disease compared with those with seronegative disease .
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Due to lack of well-controlled clinical trials, the effect of tea in the progression of neurodegenerative disorders has not been studied on a large scale. The protective effect of EGCG against neuronal diseases may involve its radical scavenging and iron chelating activity and/or regulation of antioxidant protective enzymes. Reduced risk for Parkinson’s disease was observed for more than or equal to 2 cups/day of tea consumption and two or more cola drinks/day. The associations for tea and cola drinks were not affected by smoking or coffee consumption . A case control study was conducted in China to examine the relationship between coffee and tea drinking, cigarette smoking, and other environmental factors and risk of Parkinson’s disease. It was found that one unit of coffee and tea would lead to 22% and 28% risk reduction, respectively, of Parkinson’s disease demonstrating a dose-dependent protective effect of coffee and tea in an ethnic Chinese population . The association of coffee and tea consumption with the risk of incident Parkinson’s disease among 29,335 Finnish subjects aged 25 to 74 years without a history of Parkinson’s disease at baseline was investigated. There were followed up for 12.9 years and during this time, 102 men and 98 women developed an incident Parkinson’s disease. It was noted that subjects who habitually drank ≥ 3 cups of tea/day had a reduced risk of incident Parkinson’s disease . In the Singapore Chinese Health Study, a prospective cohort of 63,257 Chinese men and women, all 157 incident Parkinson’s disease cases were identified. There was an inverse relationship of black tea with Parkinson’s disease risk that was not confounded by total caffeine intake or tobacco smoking, while green tea was unrelated to Parkinson’s disease risk .
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A typical cup of green tea usually contains 250–350 mg tea solids, of which 30–42% are catechins and 3–6% caffeine . The major active constituents of tea are catechins, and among them, EGCG is the most potent and much of the anticarcinogenic effect of green tea is predominantly credited to it. Some catechins are oxidized or condensed to theaflavins and thearubigins during fermentation of fresh tea leaves and are responsible for the bitter taste and dark color of black tea. Black tea contains mainly thearubigins, theaflavins, tea articles flavonols and catechins. The total polyphenol content of green and black teas is similar, but with different types of flavonoids present due to the degree of oxidation during processing .
It is increasingly appreciated that tea contains polyphenols and other components that may reduce the risk of developing chronic diseases such as cancer, cardiovascular diseases, arthritis and diabetes. More recently, the beneficial properties associated with daily consumption of green tea are getting better recognized. Particularly interesting are the studies which report that green tea reduces the risk of cancer, which is the major cause of mortality throughout the world. It has become increasingly clear that tea acts as a chemopreventive agent against a wide range of cancers. To evaluate the efficacy of tea against cancer, clinical trials are being conducted. Encouraging data from many trials are available and from many ongoing trials are awaited. However, results from human studies are not always positive, may be, due to the fact that the higher doses of tea are used in animal studies than those consumed by humans and in animal studies, the experimental conditions are generally optimized for the evaluation of a protective effect. Large scale well-controlled human clinical trials are necessary to establish the health promoting effects of tea consumption. Only based on these findings, recommendations to human population could be made.
Earliest documented cancer preventive effect of tea is our study in 1988 . Currently, there are 1000 scientific publications in the scientific literature found on PubMed documenting cancer preventive ability of tea. Several studies initiated in our laboratory and subsequently verified from many other laboratories have suggested that catechins and theaflavins found in tea may reduce the risk of various types of cancers in humans. Various reports have shown an inverse association of tea consumption with the development of certain types of cancer . The reported effects of tea on skin, prostate, lung and breast cancer in humans are shown in Table 1 .
The authors confirm that this article content has no conflicts of interest.
For all catechins, the metabolic pathways of methylation, glucuronidation and sulfation have been observed. Methylation, a major metabolic pathway, forms the metabolites 3′ and 4′- O -methyl–EC and O -methyl–EC-glucuronide, 4″- O -methyl-ECG, 4′- O -methyl-EGC, 4″- O -methyl-EGCG and 4′,4″-di- O -methyl-EGCG, and 4″- O -methyl-EGCG-3′- O -glucuronide and 3′,4′- or 3′,5′-di- O -methyl-EGCG-4″- O -glucuronide . In human liver cytosol, -EC was efficiently sulfated mainly through SULT1A1 while in the intestine, both SULT1A1 and SULT1A3 also contributed to the sulfation. -EC was not glucuronidated by human liver and small intestinal microsomes. It has also been reported that there was no confirmation of glucuronidation by human colon microsomes or by recombinant UDP-glucuronosyltransferase-1A7 , which is present in stomach and esophagus, but not in liver. -EC was efficiently glucuronidated with the formation of two glucuronides in rat liver microsomes. Sulfation of -EC was a major pathway in human liver and intestine without glucuronidation . The absorption of green tea catechins in the small intestine is quite small. Flavanols are absorbed without deconjugation or hydrolysis and pass through biological membranes. The greater part of ingested green tea catechins reaches the large intestine and encounters the colonic microflora, with further hydrolysis of glycosides into aglycones and extensive transformation into various aromatic acids like phenylvalerolactones and hydroxyphenylpropionic acids . In humans, plasma bioavailability of green tea catechins is very low. After the administration of either 697 mg of green tea or 547 mg of black tea to healthy volunteers, plasma EGC and EC content was 0.26–0.75% compared with EGCG and ECG with 0.07–0.20% with similar observations in urine . With a single catechin, plasma concentration was found to be 1.53 M at a dose of 1050 mg for -EC, 3.1 μM at a dose of 664 mg for ECG, 5 μM at a dose of 459 mg for EGC and 6.35 μM at a dose of 1600 mg for EGCG . Six metabolites were identified in human urine: -EC-glucuronide, three -EC-sulfates, two O -methyl–EC-sulfates. Microbial metabolites -5–γ-valerolactone, and their glucuronide conjugates were also present. The major pathway for the elimination of EGCG is the biliary excretion. The total amount of metabolites excreted in urine is associated with maximum plasma concentrations. Urinary recovery was 0.5–6% for some tea catechins . The half-lives of flavanols are 2–3 h in plasma, except EGCG, which is eliminated more slowly probably due to higher biliary excretion and greater complexing with plasma proteins .
The authors are thankful for support to National Institutes of Health, National Cancer Institute Grants R01CA120451 and R03CA153961 .
Various studies have demonstrated the relationship between tea consumption and threat of lung cancer. Tea drinking was associated with reduced risk of lung cancer in male cigarette smokers in a case control study in Uruguay . In a population-based case-control study in Shanghai, China, consumption of green tea was associated with a reduced risk of lung cancer among non-smoking women and the risk decreased with increasing consumption . There was a significant decrease in urinary 8-hydroxydeoxyguanosine after drinking decaffeinated green tea among smokers over a 4 month-period in a randomized controlled tea intervention phase II trial . In a case control study, a protective effect of frequent, daily or several times/week black tea drinking appeared among non-smoking women . The maximum tolerated dose of green tea extract in patients with advanced lung cancer was determined by Laurie et al. Seventeen patients with advanced lung cancer were given oral doses of GTE once daily, starting with a dose of 0.5 g/m 2 /day with increasing doses. The maximum tolerated dose of GTE was found to be 3 g/m 2 /day without grade 3 or 4 toxicity . A case-control study was conducted on 241 lung cancer patients in Taiwan and the effects of smoking, green tea consumption, IGF1, IGF2, and IGFBP3 polymorphisms were evaluated on lung cancer risk. It was found that lung cancer cases had a higher proportion of smoking, green tea consumption of 1 cup/day .
Among many dietary agents investigated for chemopreventive properties against prostate cancer , green tea and its constituent polyphenols have received much attention. A Phase II trial was conducted in patients with androgen independent prostate carcinoma to investigate the explored the antineoplastic effects of green tea. Forty two patients asymptomatic who had manifested, progressive prostate specific antigen elevation with hormone therapy were evaluated. Six grams of green tea per day orally in 6 divided doses were given to patients and each dose contained 100 calories and 46 mg of caffeine. A decline in more than or equal to 50% in the baseline PSA value occurred in a single patient and it was not continued beyond 2 months. Median change in the PSA value increased by 43% at the end of the first month. Grade 1 or 2 green tea toxicity occurred in 69% of patients, along with Grade 3 toxicity and one episode of Grade 4 toxicity . In Hangzhou, southeast China, a case-control study was conducted in 130 incident patients with histologically confirmed adenocarcinoma of the prostate. The risk of PCa declined with increasing frequency, duration and quantity of green tea consumption and there were significant dose-response relationships, suggesting preventive effects of green tea . The efficacy of green tea capsules was tested on patients with hormone refractory prostate cancer by Choan et al. . Efficacy of green tea, prescribed as an alternative complementary formulation was tested on HRPCa. PSA was the primary endpoint and estimates after a minimum of 2 months of therapy. It was found that 12 patients reported at least one side effect among 19 patients enrolled into the study. The minimum 2 months of therapy was not completed by 4 patients and 15 patients completed at least 2 months of therapy. Within 2 months of starting therapy, progressive disease was noted in 9 of these patients and 6 patients developed it after additional 1 to 4 months of therapy. Therefore, based on the results of this study, it was concluded that green tea had minimal clinical activity against HRPCa . In high-grade prostate intraepithelial neoplasia volunteers, a clinical trial was conducted to assess the safety and efficacy of green tea catechins for the chemoprevention of PCa. Daily treatment consisted of three green tea catechins capsules 200 mg each. Only one tumor was diagnosed among the 30 green tea catechins-treated men with an incidence of 3%, whereas nine cancers were found among the 30 placebo-treated men with an incidence of 30% after 1 year. There was no significant change in total PSA between the two arms, but green tea catechins-treated men showed values constantly lower with respect to placebo-treated ones. International Prostate Symptom Score and quality of life scores of green tea catechins-treated men with coexistent benign prostate hyperplasia, a condition prevalent in older men were also improved. There were no reports of significant side effects and administration of green tea catechins also reduced lower urinary tract symptoms . Green tea consumption habit of 49,920 men aged 40–69 years was investigated in the Japan Public Health Center-based prospective study. During that time, 404 men were newly diagnosed with PCa, of which 114 had advanced cases, 271 were localized, and 19 were of an undetermined stage. It was established that localized PCa was not affected by the consumption of green tea, there was a dose-dependent decrease in the risk of advanced PCa by intake of green tea . It has been reported that there was a significant reduction in serum levels of PSA, hepatocyte growth factor and vascular endothelial growth factor in men with prostate cancer after brief treatment with green tea extract containing EGCG , with no elevation of liver enzymes . In PCa patients scheduled to undergo radical prostatectomy, a randomized, double-blind, placebo-controlled trial of Polyphenon E was conducted to determine the bioavailability of GTP in prostate tissue and to measure its effects on systemic and tissue biomarkers of PCa. Polyphenon E or placebo daily was given to patients for 3 to 6 weeks before surgery. Treatment with Polyphenon E caused promising but not statistically significant changes in the levels of serum PSA, serum insulin-like growth factor axis, and oxidative DNA damage in blood leukocytes. In the prostatectomy tissue, tissue biomarkers of cell proliferation, apoptosis, and angiogenesis did not differ between the treatments. Patients receiving Polyphenon E had a decrease in Gleason score between biopsy and surgical specimens but it was not statistically significant .
Green tea contains characteristic polyphenolic compounds, -epigallocatechin-3-gallate , -epigallocatechin , -epicatechin-3-gallate and -epicatechin . Flavonols, including quercetin, kaempferol, myricitin and their glycosides are also present in tea.
Tea consumption has been reported to have beneficial effects against several types of cancers. Consumption of green tea was associated with a lower risk of esophageal cancer in a case-control study of esophageal cancer patients in Shanghai . In a prospective cohort study in Yoshimi town in Saitama Prefecture, respondents were divided into three groups according to daily consumption of green tea: less than 3 cups, from 4 to 9 cups, and more than 10 cups. Individuals who consumed more than 10 cups of green tea/day showed remarkable reduction of relative risk for lung, colon, and liver cancers . It has been reported in a study that consumption of black tea reduces colon cancer risk in both men and women . The association between green tea consumption and colorectal cancer risk was evaluated in a population-based prospective cohort stud which included 60,567 Chinese men aged 40–74 years at baseline. The subjects were followed up for 5 years and 243 incident cases of colorectal cancer were identified. Regular green tea consumption of at least three times/week for more than six consecutive months was related with reduced risk of colorectal cancer in non-smokers and the risk decreased with the increased amount of green tea consumption. Each 2 g rise of intake of dry green tea leaves/day was associated with a 12% reduction in risk of colorectal cancer. However, there was no significant association of green tea consumption with the risk of colorectal cancer among smokers suggesting that regular consumption of green tea may reduce colorectal cancer risk among non-smokers . A total of 13 epidemiological studies consisting of six case-control and seven prospective cohort studies were included in a meta-analysis to evaluate the association between tea consumption and the risk of primary liver cancer. An inverse association with a borderline significance was found between tea consumption and primary liver cancer with demonstrated preventive effects of tea intake on the development of primary liver cancer in both men and women. It was concluded that green tea consumption was associated with a moderate reduction in risk for primary liver cancer . The association between green tea drinking and the risk of pancreatic cancer was investigated in a population-based case-control study in urban Shanghai with recruitment of 908 patients of pancreatic cancer and 1067 healthy controls. Interview questionnaire was filled by the subjects to give information on tea drinking, type of tea, amount of tea consumption, temperature of tea, and the duration of regular tea drinking. Regular green tea drinking was associated with 32% reduction of pancreatic cancer risk as compared to those who did not drink tea regularly in women with increased consumption and longer duration of tea drinking associated with reduced pancreatic cancer risk. Lower temperature of tea was associated with reduced risk of pancreatic cancer in both men and women, irrespective of the amount or duration of tea drinking among regular tea drinkers . In case control studies on the relationship between gastric cancer and tea consumption conducted in China and Japan, a significant inverse relationship was found in four studies and an insignificant inverse relationship was found in two studies . does lipton diet green tea help lose weight

Herbal beverages herbal tea articles Bioactive compounds and their role in disease risk reduction

Chamomile is a member of Asteraceae or Compositae family and is represented by several varieties, namely Chamomilla recutita, Matricaria chamomilla and Chamaemelum nobile . Chamomile tea is widely consumed in Europe. Chamomile tea, is brewed from dried flower heads. The main constituents include phenolic compounds, primarily the flavonoids apigenin, quercetin, patuletin, and luteolin. 74 The principal compounds of the essential oil are the terpenoids alpha-bisabolol and azulenes, including chamazulene. Chamomile has moderate antioxidant and antimicrobial activities, and significant antiplatelet activity in vitro . 74 In addition, animal studies have shown potent anti-inflammatory, antimutagenic and cholesterol-lowering activities for chamomile. Furthermore, some antispasmotic and anxiolytic effects of chamomile tea have also been demonstrated. 74
Coumarins are lactones of cis- O -hydroxycinnamic acid derivatives and exist in the free form or as glycosides. In foods, simple coumarines, furanocoumarines and pyranocoumarins are found. 3
Flavonoids are synthesized by condensation of a phenylpropanoid compound with three molecules of malonyl coenzyme A. This reaction is catalyzed by the enzyme chalcone synthase that leads to the formation of chalcones. The chalcones are subsequently cyclized under acidic conditions to form flavonoids. 3 There are different subclasses of flavonoids, namely flavones, flavonols, flavonones, flavononols, isoflavones, anthocyanidins and flavanols. Flavones and flavonols are present as aglycones in foods. 3 They have similar C ring structures with a double bond at the 2–3 positions. Flavones lack a hydroxyl group at the third position. 3 Flavonols , flavones , flavanols , flavanones , anthocyanidins , and isoflavones are the commonly found flavonoids in the human diet. Flavonoids, namely catechin, quercetin, kaempferol, rutin, apigenin, and isorhamnetin are constituents of the aqueous infusions of flower, leaf and seed of Sideritis condensate 11 . In addition, flower infusion prepared within 10 min time contained 15 mg of isorhamnetin per gram of dry matter.
Fresh flower and buds of Tanner’s Cassia and cuttings of dehydrated immature fruit and preparation of herbal tea of bael.
Herbal beverages are habitually used as part of the normal diet in some populations in the world and trend of using them among others is progressively increasing. However, very limited published information is available on safety of herbs and herbal beverages, and herb-herb as well as herb-therapeutic drug interactions. It should be noteworthy that herbal beverages are prepared to maintain plalatable chracteristics of a social beverage thus they are less strong in their flavour and their bioactive compounds are present in smaller amounts due to the dilution as compared to those of herbal preparations intended to use as medicine. For instance, in Sri Lankan traditional and Ayurvedic medical system decoctions to be used as medicine are prepared by boiling dried or fresh herbs in 8 cups of water until volume is reduced to one cup.
Several preparations of rosehip fruits and seeds demonstrated antioxidant and antiinflammatory activities. 81 R. canina L. fruits have a high content of ascorbic acid, and phenolics, including flavonoids, which render antioxidant activity as well as several other beneficial bioactivities. 82
Yerba mate is widely consumed by native people as social and medicinal beverage in South America for centuries and unlike other herbal beverages it contains caffeine. Several health promoting properties such as hepatoprotective, diuretic as well as central nervous system stimulating effects have been reported for yerba mate. 66 Furthermore, other studies have demonstrated its antioxidant, anti-inflammatory, antimutagenic and lipid lowering activities. 67 , 68 , 69 , 70 The main bioactive compounds in yerba mate responsible for its activities were identified as caffeoyl derivatives such as caffeic acid, mono- and dicaffeoylquinic acids, methylxanthines and flavonoids, namely rutin, quercetin and kaempferol. 71 In a separate study, it was demonstrated that yerba mate and its bioactive compounds regulate the expression of genes related to adipogenesis. 72 Yerba mate extract down-regulated the expression of genes responsible for adipogenesis, such as Creb-1 and C/EBPα. Furthermore, the extract up-regulated the expression of genes related to the inhibition of adipogenesis, including Dlk1, Gata2, Gata3, Klf2, Lrp5, Pparγ2, Sfrp1, Tcf7l2, Wnt10b, and Wnt3a. 72
Herbal beverages have been used as natural part of the food culture in countries where traditional medicines are widely used. For instance, herbal teas prepared from Aegle marmelos , Cassia auriculata , Aerva lanata , and Hemidesmus indicus are common social beverages of food cultures in India and Sri Lanka. China is another country where combined herbal teas are often drank on a daily basis to promote health and reduce the risk of certain health-related issues of different severity as simple as cold to diseases of liver and other organs.
African rooibos , borututu and honey bush tisanes are popular South African herbal teas. Traditional medicinal uses of rooibos in South Africa include alleviation of infantile colic, allergies, asthma and dermatological problems. Furthermore, decoction of honey bush is used as a restorative and as an expectorant in chronic catarrh and pulmonary tuberculosis. 60 Mckay and Bulmbergare 61 reported that rooibos is rich in polyphenols and a rare source of the dietary dihydrochalcones, namely aspalathin and nothofagin. In addition, major polyphenols in honey bush are xanthone mangiferin and the flavonones, hesperitin and isokuranetin. 62 Both rooibos and honey bush teas have demonstrated potent antioxidant and antimutagenic activities in vitro . Rooibos tea also renders beneficial effects for heart health. It was reported that chrysoeriol, which is present at low levels in Rooibos is a potential agent in preventing and treating vascular diseases in humans. 63 Chrysoeriol is able to inhibit the migration of smooth muscle cells inside the aorta, a key cause of atherosclerosis. Furthermore, Rooibos tea has demonstrated ACE inhibitory activities and reducing several of the pertinent biomarkers associated with cardiovascular disease. 64 , 65
Evidences on medicinal claims for Aegle marmelos .
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Centella asiatica is an herbal tea commonly used by Asian populations. The dried whole herb as a single ingredient or mixed with other products such as garlic, coriander or ginger is used. This herb is known to increase the activity of antioxidant enzymes, namely superoxide dismutase, catalase, and glutathione peroxidase. 37 C. asiatica consists of a number of bioactive compounds such as alkaloids, terpenoids and saponins. 38 The principle triterpenoids identified in this herb include asiatic acid, madecassic acid, asiaticoside and madecassoside, among others. 39 In addition, C. asiatica is a rich source of bioactive polyacetylenes. 18 Govindan et al. 40 identified a polyacetylene compound, cadiyenol, from the areal part of the plant. They further demonstrated that cadiyenol was capable of inducing cell apoptosis by 63% at 28 μM concentration within 24 h in mouse lymphoma cells . In addition, the compound also reduced nitric oxide production by 70% in lipopolysacahrride activated mouse macrophages at 24 μM level.
Antioxidants are known for their ability to inhibit or delay the oxidation of other molecules in food and biological systems. They are protective against oxidative stress via different mechanisms and modes of action that are often independent of their antioxidant effect and may render their effects cooperatively via several mechanisms. These modes of action include free radical scavenging, singlet oxygen quenching, inactivation of peroxides and other ROS, metal ion chelation, quenching of secondary oxidation products, and inhibition of pro-oxidative enzymes, among others. 7
‘ Dagcayi ’ is a popular herbal beverage in Turkey prepared from infusion of S. condensate. In a recent study, phenolic composition of aquous infusions of Dagcayi was reported. 11 Dried aerial part of the plant is generally used to infuse the tea. Hydroxybenzoic as well as hydroxycinnamic acids were identified in flower, leaf and seed extracts of S. condensate. Phenolic composition of S. condensate changed based on the infusion temperature, time duration and part of the plant used for infusion. The phenolic acid identified in all plant parts examined was p- coumaric acid and its content ranged from 10 to 398 μg/g of dry matter of different plant parts, namely flower, leaf and seed. Chlorogenic acid was detected only at the steeping temperature of 60 °C. 11
Source: Data adapted from Bender et al. 83 .

Phenolic compounds are ubiquitous in plant organs. They are secondary metabolites consisting of an aromatic ring with different degrees of hydroxylation. 3 Phenolics are derived from biosynthetic precursors such as pyruvate, acetate, aromatic amino acids such as phenylalanine and tyrosine, acetyl CoA and malonyl CoA following the pentose phosphate, shikimate, and phenylpropanoid metabolism pathways. 10 Phenolic compounds occurring in herbal beverages include phenolic acids, coumarins, flavonoids, tannins, lignans and lignins.
According to a review by Singh et al 86 the herb C. asiatica might cause liver problems, stomach upset, nausea, and drowsiness. Choi et al 87 reviewed the herb drug interactions and specially focused on the effect of herbs on metabolic enzymes and transporters. Active compounds of some herbs may inhibit phase 1 and 2 metabolic enzymes thus affect the drug metabolism. In addition, concentrated form of some herbs, such as green tea can cause detrimental effects, namely liver damage, interaction with medications, interaction with metabolic enzymes and other natural ingredients. 88 , 89
Kombucha tea is a health beverage prepared by fermentation of black tea brew and sugar with a symbiotic culture of acetic acid bacteria and yeasts reported to have potential health effects. 73 Aloulau et al 73 demonstrated that compared to black tea, kombucha tea was an effective inhibitor of α-amylase and lipase activities in the plasma and pancreas of diabetic rats. Further, kombucha tea demonstrated higher suppressor activity of increased blood glucose levels than that of black tea. In addition, kombucha induced a marked delay in the absorption of LDL-cholesterol and triglycerides and a significant increase in HDL-cholesterol. According to histological analysis it exerted an ameliorative action on the pancreases and efficiently protected the liver-kidney functions of diabetic rats. This was further evidenced by significant decreases in aspartate transaminase, alanine transaminase, and gamma-glytamyl transpeptidase activities in the plasma, as well as in the creatinine and urea contents of diabetic rats. 73
Antioxidants are naturally present in many foods. Further, they can be synthesized, similar to their natural counterparts, such as synthetic vitamins C and E. Synthetic antioxidants generally contain of a phenolic ring and one or more hydroxyl substituents. Synthetic antioxidants that are still used by the food industry include butylated hydroxyanisole , butylated hydroxytoluene , propyl gallate , and tert -butylhydroquinone . However, there are concerns associated with potential carcinogenic effect of some of these synthetic antioxidants at high concentrations in animal models which limits their use in food applications and a desire by the consumers to have green label products devoid of synthetic additives. 7
b Department of Biochemistry, Memorial University of Newfoundland St. John’s, NL, A1B 3X9, Canada
Several studies have shown the antioxidant, hypocholesterolemic, anti-parasitic, anti-aging, and anticancer properties of chamomile. 75 , 76 , 77 Chamomile has long been known as a treatment for inflammatory diseases. It was demonstrated the chamomile treatment inhibited the release of LPS-induced prostaglandin E in RAW 264.7 macrophages in vitro . 77 This effect was found to be due to inhibition of COX-2 enzyme activity by chamomile extracts. Furthermore, chamomile caused reduction in LPS-induced COX-2 mRNA and protein expression, without affecting COX-1 expression. 77 A small percentage of people are sensitive to chamomile and develop allergic reactions. 78 Evidence of herb-drug interactions of chamomile is not well documented, and further studies are needed to reach any final conclusions. 78
There are no conflict of interest to report.
Polyacetylenes are a group of bioactive compounds consisting of carbon-carbon triple bond or alkynyl functional group. 18 Aliphatic C 17 -polyacetylenes of the falcarinol type such as falcarinol and falcarindiol are widely distributed in the Apiaceae and Araliaceae families. Polyacetylenes of the falcarinol-type are formed from oleic acid by dehydrogenation that leads to the formation of C 18 -acetylenes crepenynic acid and dehydrocrepenynic acid, which are then transformed to C 17 -acetylenes upon β -oxidation. 18 Health promoting properties and the content of polyacetylenes of a number of traditional medicinal herbs have been investigated during past few decades. Herbs such as American ginseng root , Peucedanum praeruptorum , Echinacea pallida , Bupleurum spinosum and Atractylodes lancea have been reported to contain polyacetylenes 19 , 20 , 21 , 22 .
Two classes of phenolic acids, hydroxybenzoic acids and hydroxycinnamic acids are found in plants. 3 Hydroxybenzoic acids include gallic, p- hydroxybenzoic, vanillic, syringic, and protocatechuic acids, among others. The hydroxycinnamic acids, better known as pheylpropanoids , include p- coumaric, caffeic, ferulic, and sinapic acids. 3 Herbal beverages have been reported to include a number of phenolic acids.
Herbal beverages are potential rich sources of phytochemicals that may help in reducing disease risk conditions and therefore in the management of NCDs. A number of herbal beverages are consumed globally. Though bioactivities of some herbal beverages are known through preclinical studies, further analytical and clinical research is warranted in order to investigate the bioactive compounds that render such effects and their mode of actions in disease risk reduction and health promotion needs to be verified.
Herbal beverages herbal tea articles Bioactive compounds and their role in disease risk reduction
Herbal beverages herbal tea articles Bioactive compounds and their role in disease risk reduction
Dried flower buds, flowers and leaves of Tanner’s Cassia have gained wide popularity as herbal teas in countries such as India and Sri Lanka. Furthermore, plant parts of Tanner’s Cassia have been used as an alternative therapeutic agent particularly in controlling hyperglycemic conditions in traditional medical system. Methanolic extracts of Cassia flowers inhibited α-glucosidase activity in vivo and in vitro . 55 Further, the flower and leaf extracts of Cassia exhibited antihyperglycemic effects in streptozotocin-induced experimental diabetes. 56 , 57 In addition, the aqueous extract of Cassia inhibited lipid peroxidation in the brain of diabetic rats. 58 Several phenolic compounds, namely catechin, epicatechin and procyanidin B 1 were identified in aqueous alcoholic extract of cassia seeds. 59 Puranik et al. 59 reported on cardiovascular safety and good tolerance of Cassia seed extracts without any adverse effects in male and female rats. However, Cassia seed extracts obtained using supercritical fluid extraction interfered with the absorption of metformin when co-administered with extracts in a rat model. 59
Lignans are compounds that comprise of two coupled phenylpropanoid units linked by the central carbons of their side chains. 3 The common plant lignans found in the human diet include secoisolariciresinol, matairesinol, lariciresinol, pinoresinol and syringaresinol. 12 Secoisolariciresinol, and matairesinol are readily converted to mammalian lignans, enterodiol and enterolactone, respectively, by intestinal microflora in the human gut and are known to exert strong antioxidant and estrogenic activities. 12
Selected Herbal beverages commonly consumed in different parts of the world.
Lignins are formed via polymerization of a mixture of the three monolignols, namely p- coumaryl, sinapyl and coniferyl alcohols. 13 Additional compounds are incorporated into lignin in small quantities. They include coniferaldehyde, sinapaldehyde, dihydroconiferyl alcohol, 5-hydroxyconiferyl alcohol, herbal tea articles tyramine ferulate and p -hydroxy-3-methoxybenzaldehyde, among others. 14
Carotenoids are widespread pigments with yellow, orange, and red colours. They have pro-vitamin A and antioxidant activities. Carotenoids belong to hydrocarbons with a 40-carbon atom skeleton of 8 isoprene units. Their structures may be cyclized at one or both ends, and have different number of hydrogen atoms, or possess oxygen-containing functional groups, the latter named as xanthophylls. Common carotenes in the human diet include β -carotene, α-carotene and lycopene, whereas xanthophylls include lutein, zeaxanthine, cryptoxanthin, canthaxanthin, astaxanthin and fucoxanthin. Major provitamin A active carotenoids are β -carotene, α-carotene and cryptoxanthin.
Herbal beverages when consumed within a balanced diet, may improve the antioxidant status, and reduce oxidative stress in humans. 8 In addition, many commonly consumed herbal beverages do not contain any detectable caffeine levels as in coffee and tea. Health Canada categorizes herbal beverages under natural health products . However, according to Health Canada moderate consumption of selected herbal teas such as citrus peel, lemon balm, ginger, orange peel and rosehip is recommended during pregnancy and breastfeeding. 9
A. marmelos, commonly known as bael, is a plant native to Southeast Asia. It is a slow growing, subtropical tree and is grown in India, Sri Lanka, Pakistan, Bangladesh, Burma, Thailand, and other Southeast Asian countries. Bael fruit is a rich source of coumarins, vitamin C, and riboflavin. The leaves, stems, and bark as well as fruits are known in traditional medicine for dysentery and various other intestinal complaints . The leaves are also widely used to treat diarrhoea. In addition, bael is a potent radioprotective, analgesic, antihyperglycemic, antidyslipidemic, anticancer, and antidiabetic agent. 42 , 43 , 44 , 45 , 46 , 47 The total phenolic content and total flavonoid content of bael fruit were reported to be 87 mg gallic acid eq/g of dry weight and 15 mg catechin eq/g dw, respectively. 48 In addition, the content of carotenoids and ascorbic acid of bael fruit were reported to be 3.3 and 26 mg/100 g dw, respectively. Furthermore, monoterpenes and sesquiterpenes were reported as its dominant volatile compounds. 48 Limonene is the major constituent producing the characteristic bael fruit flavor, among others. In addition, coumarins such as marmelosin, marmesin, and imperatorin, as well as alkaloids, namely aeglin, and aegelenine were also isolated from different parts of bael. 49 The extract of leaf, root, stem and the fruit demonstrated high antioxidant activities as determined by the 2,2-diphenyl-1-picrylhydrazyl scavenging activity, and ferric reducing antioxidant activity power assays. Furthermore, several bioactivities such as antidiabetic, antihyperlipidemic, antiviral, antifungal, antibacterial, anticancer, and anti-inflammatory were reported in association with different parts of bael tree. 26 , 50 The antidiabetic effect of the fruit extract is probably due to the presence of coumarins, which potentiate insulin secretion from existing beta cells of the isles of langerhans. 51 In Sri Lanka, dried buds and flowers and immature fruits are prepared as herbal tea infusions to replace the popular tea prepared from Camelia sinensis .
a Department of Applied Nutrition, Wayamba University of Sri Lanka, Makandura, Gonawila, 60170, Sri Lanka
There is a renewed interest in natural non-nutrient antioxidative compounds in reducing the incidence and severity of NCDs. Antioxidant compounds are widely distributed in plant materials, animal tissues and microorganisms. Fruits, vegetables, cereals, legumes, oilseeds, teas and certain spices are important sources of plant-derived antioxidants. 3
Peer review under responsibility of The Center for Food and Biomolecules, National Taiwan University.
In general, herbal beverages are prepared from natural ingredients of different morphological plant parts, namely leaves, stems, roots, fruits, buds and flowers. Herbal teas/beverages are rich sources of natural bioactive compounds such as carotenoids, phenolic acids, flavonoids, coumarins, alkaloids, polyacetylenes, saponins and terpenoids, among others. Scientific evidence shows that these bioactive compounds render a myriad of biological effects, such as antioxidant, antibacterial, antiviral, antiinflammatory, antiallergic, antithrombotic and vasodilatory action, as well as antimutagenicity, anticarcinogenicity and antiaging effects, among others. 4 , 5 , 6 This contribution provides an overview of constituent antioxidants, and bioactivities of herbal beverages.
Oxygen radical absorbance capacity and cellular antioxidant activity of herbal beverages.
The commonly used tea is a beverage made from leaves and buds or twigs of the plant Camellia sinensis , and is only second to water, the most consumed beverage in the World. There are basically four major types of true teas, namely black tea, oolong tea, green tea, and white tea. Nevertheless, the term herbal tea/beverage usually refers to infusions with fruit or other herbs that do not contain Carmellia sinesis . Herbal beverages are also called tisane, herbal infusion, or botanical infusion to avoid confusion with true teas. Herbal beverages can be made with fresh or dried flowers, immature fruits, leaves, seeds, and/or roots by steeping or boiling of the source materials including herbs.
Phenolic acids and flavonoid contents of Sideritis condensate steeped at 100  C for 10 or 30 min.
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Herbal teas have been consumed as social drinks for centuries. In addition they are also used as alternative herbal medicines to treat a number of ailments. In the modern societies they are used for reducing the risk conditions of non-communicable diseases such as type 2 diabetes, hypertension, dyslipidemia and cancer. 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 Table 3 summarizes selected information on medicinal claims for herbal concentrates of A. marmelos .
Peppermint tea, brewed from Mentha piperita leaves, is a commonly consumed tisane that gives calming effect in the body and is popular in Europe and North Africa. Health benefits reported for peppermint tea include in vitro antibacterial activity against a range of pathogenic bacteria and antioxidant activity. 79 , 80 The phenolic compounds reported in the leaves of M. piperita include rosmarinic acid and flavonoids.
Terpenes and terpenoid derivatives are secondary metabolites which originate from isoprene units. 16 The C5H8 isoprene units polymerise and subsequently produce different classes of terpenoids that include hemiterpenes consisting of a single C5 isoprene unit, monoterpenes , sesquiterpenes , diterpenes , sesterterpenes , triterpenes , carotenoids and polyterpenes consisting of long chains of many isoprene units. Triterpene group of compounds include sterols and triterpenes, which are accumulated as glycosides in plants. Saponins are glycosylated secondary metabolites with surface-active properties. Some of these saponins are valuable starting materials for the synthesis of steroidal drugs. 17
In Japan, a number of herbal teas such as Arabian jasmine, Balsam pear, barley grass, guava, hardy rubber tree, Japanese persimmon, Jobs tears, and Wolof berry tea are consumed for health promotion. 41 Total phenolic content of Arabian jasmine, balsam pear, barley grass, chameleon plant, guava, hardy rubber tree, Japanese persimmon, jobs tears, and wolf berry tea were 101, 15, 11, 83, 43, 41,4 and 17 mg tannic acid equivalents /g of herb , respectively. The antioxidant activity of these herbal teas ranged from 7 to 173 mmol/L as copper reducing power.
Excessive generation of reactive oxygen species in the body causes oxidative stress, an injurious process leading to the oxidation of biomolecules such as proteins, lipids, carbohydrates and DNA. Oxidative stress is well known for its pivotal role in the etiology of several non-communicable diseases such as cardiovascular diseases, arthritis, type 2 diabetes, different types of cancer, autoimmune diseases and neurodegenerative disorders, among others. 1 The human body has endogenous antioxidant defense mechanisms those act simultaneously against ROS. These include enzymes , low-molecular-weight antioxidants and certain vitamins as well as carotenoids. 2 However, external sources of antioxidants are needed to prevent oxidative damage in the human body once internal antioxidant defense systems are challenged by over exposure to free radicals and other ROS.
Herbal beverages, commonly known as teas, have gained popularity among health conscious consumers. They have penetrated into an emerging niche market along with other popular beverages such as tea, coffee and cocoa which are also prepared using plant materials. In addition, a rapidly growing segment of the population uses herbal beverages for slimming, weight loss and a number of other cosmetic purposes.
According to Bender et al., 83 in vitro oxygen radical absorbance capacity and ex vivo cellular antioxidant capacity of yerba mate, peppermint tea, sage and rosehip fruit infusions in HaCat human keratinocytes cell line were found to vary considerably . Sage is commonly used to prepare beverages as well as a flavoring agent in foods. Several health benefits such as antitumoral, antibacterial and antiinflammatory properties of sage have been reported. 84 , 85
Generally bael is considered to be safe but only few studies have been conducted on its toxicity. Das et al 52 examined the toxic effects of aqueous extract of the leaves of bael and reported that 50 mg/100 g of body weight of male albino Wistar strain rats did not exhibit any toxicity in the liver and kidneys. Further, it was demonstrated that neither gross abnormalities nor histopathological changes were observed in the heart, liver, kidneys, testis, spleen and brain after continuous administration of 50 mg/kg body weight of the extracts of A. marmelos intraperitoneally for 14 d. 53 In addition, the aqueous extract of bael fruit was not reported to be mutagenic to Salmonella typhimurium strain TA 100 in the Ames assay. 54
Herbal teas consist of one or more herbal substances intended for oral consumption and prepared by means of decoction, infusion or maceration. Generally the tea is prepared immediately before use. However, ready-to-serve bottled herbal beverages are becoming popular. Herbal teas are usually supplied in bulk form or in sachets. The herbal substance used in tea formulations may be processed in advance by means of drying, comminuting and crushing. Therefore, commercially available products may be in different forms such as whole dried plant parts, dried powder, dried particles within tea bags, as well as granulates, and solutions which can be consumed directly. Table 1 presents selected examples of herbal beverages commonly used by populations around the world to boost optimum health as well as for reducing the risk of a number of disease conditions such as hyperglycemia, dyslipidaemia, cancer, and hypercholesterolemia.
Tannins are composed of a group of compounds with a wide diversity in structure and have ability to bind and precipitate proteins. 3 Tannins are classified into three groups, namely condensed tannins, hydrolysable tannins and complex tannins. 15
There is a renewed interest in non-nutritive bioactive compounds of foods and beverages as ‘lifespan nutrients’ in the risk reduction of non-communicable diseases. Herbal beverages, consumed as part of a balanced diet, may improve the antioxidant status and enhance the overall health status. Herbal teas/beverages are rich sources of natural bioactive compounds such as carotenoids, phenolic acids, flavonoids, coumarins, alkaloids, polyacetylenes, saponins and terpenoids, among others. A wealth of available scientific evidence demonstrates that natural bioactive compounds render a number of diversified biological effects, such as antioxidant, antibacterial, antiviral, antiinflammatory, antiallergic, antithrombotic and vasodilatory actions, as well as antimutagenicity, anticarcinogenicity and antiaging effects. A number of herbal beverages are consumed globally and some beverages have gained more popularity than others depending on their geographical origin. However, in the era of globalization, ethnic barriers have gradually been removed and such commodities although from different areas, are now universally available as international health-pro products.
Source: Data adapted from Kara et al. herbal tea research articles

2021 State of the Industry Tea’s versatility, healthfulness appeals to the masses 2021 tea articles 2021

In Beverage Industry ’s June eMagazine, New York-based Nielsen reported $70 billion in tea sales for the 52 weeks ending April 17, an 11.3% year-over-year increase. Among the sub-segments, liquid tea notched $3.4 billion in dollar sales ; RTD tea saw sales of $142 million ; and kombucha, $597 million .
Canned and bottled teas, the largest subcategory, generated year-over-year dollar sales of $4.1 billion, representing a 5.8% increase, IRI reports. Other subcategories with strong growth were refrigerated teas with sales of $1.8 billion and tea bags/loose-leaf teas saw sales of $1.3 billion .
In June, Bigelow Tea, Fairfield, Conn., added two new Bigelow plus Vitamin C bagged teas to its portfolio. Available in 18-count multipacks: Bigelow Green Tea with Elderberry Plus Vitamin C, is a smooth green tea with a slightly tart berry flavor and a smoky finish, and Bigelow Lemon Echinacea Black Tea Plus Vitamin C, is a robust black tea with tart lemon and earthy Echinacea.

The pandemic and the shuttering of cafés and restaurants, however, has impacted on-premise tea sales. “The consumption of foodservice tea in the U.S. has experienced a downfall of approximately 40% in 2020,” Mamtani explained.
Each 15.5-ounce slim can contains real brewed yerba mate, which provides the same amount of caffeine as an 8-ounce cup of coffee, 13 grams of sugar, 1% juice and 60 calories. Honest Yerba Mate is available at select grocery retailers nationwide including Publix, Fresh Direct, Hannaford, Dave’s and Whole Foods Market.
In fact, tea is the second most preferred beverage in the world after water and is found in more than 80% of households, noted Kritika Mamtani, senior research analyst for chemical, materials and food at Global Market Insights, Selbyville, Del., in Beverage Industry ’s June eMagazine.
2021 State of the Industry Tea’s versatility, healthfulness appeals to the masses 2021 tea articles 2021
2021 State of the Industry Tea’s versatility, healthfulness appeals to the masses 2021 tea articles 2021
“Rising consumer awareness regarding the health benefits of tea along with the availability of variety of flavors has increased the sales of hot tea more than 15% in the past five years,” she said. Between 2017 and 2019, wholesale tea sales in the United States generated incremental growth of $12.5 billion, $12.66 billion and $12.67 billion, respectively, she added.
In the June eMagazine, Global Market Insights’ Mamtani suggested tea manufacturers focus on developing innovative tea products to attract new and existing consumers in the market. “The demand for tea is driven by major factors such as convenience, variety, easy availability, health benefits, and introduction of unique flavored and high-end specialty tea,” she explained. “Tea manufacturers should consider the above-mentioned factors to maintain sales and attract customers in the market over the forecast period.”
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Although black tea remains the No. 1 tea varietal, with about 85% of U.S. imports in 2019, green tea is surging in popularity because of its “good for the body and mind” health halo. Green teas are the least oxidized when processed, contain less caffeine, have the most flavonoids — plant-based antioxidants — which could improve fat burning, brain function and help prevent type 2 diabetes and cardiovascular disease, experts noted in the June eMagazine.
Barbara Harfmann, managing editor of Beverage Industry , visits beverage companies for cover stories and facility tours, and writes and edits for the magazine’s print and online components. tea articles 2021 She also represents the magazine at trade shows and events. She earned a Bachelor of Science in Mass Communications and Public Relations from Illinois State University.
In multi-outlets and convenience stores, the RTD tea/coffee category grew 10.2% for the 52 weeks ending May 16, according to data from Chicago-based Information Resources Inc. . This equates to $7.5 billion in sales.
Yet, there’s no shortage of new product development in the flavorful, functional tea market. Designed for consumers who crave iced tea, Lipton, through the Pepsi Lipton Partnership with PepsiCo and Unilever, introduced caffeine-free, RTD Lipton Herbal Teas in Strawberry & Mint and Orange Blossom flavors. The 16.9-ounce bottles are packaged in 12-packs and are available at major retailers including Walmart, Target, Publix, Food Lion, Giant Eagle and Meijer for a suggested retail price of $5.99.
Indigenous to South America, yerba mate is derived from the naturally caffeinated leaves of the holly tree, Ilex paraguariensis . Looking to capitalize on the use of its USDA certified organic yerba mate and Fair Trade Certified ingredients sourced from Brazil, Honest Tea, a brand of The Coca-Cola Co., Atlanta, launched Honest Yerba Mate in three organic flavors: Strawberry Pomegranate Matcha, Peach Mango Green Tea and Lemon Ginger Black Tea.
Roger Dilworth, senior analyst at New York-based Beverage Marketing Corporation , suggested that matcha could continue to grow, but likely will not evolve beyond a niche segment. “There could be a mild upturn in tea due to yerba mate,” he noted.
“The United States faced the largest drop in tea consumption of any Euromonitor-researched market in 2020,” Matthew Barry of Chicago-based Euromonitor International wrote in a July 15, 2020, blog post. “Sales of bagged and loose tea are expected to fall 13% and ready-to-drink formats are projected to fall 11%. This is a sharp reversal of the recent past, in which tea growth was modest but consistently positive.”
search Search search close search cart facebook twitter linkedin youtube Beverage Industry logo eMAGAZINE eMagazine Contact Advertise Contact Us Subscribe Newsletter NEWS Top 100 Beverage Companies State of the Beverage Industry Soft Drink Report CATEGORY FOCUS Carbonated Soft Drinks Bottled Water Juice & Juice Drinks Sports Drinks Tea and Coffee Energy Drinks & Shots Alternative Drinks Beer Beer Market Report Craft Beer Report Wine & Spirits Cannabis Beverages Plant-Based Beverages R&D Beverage R&D Features Ingredient Spotlight Beverage R&D News PACKAGING Packaging Material Packaging Equipment New Packages The Packaging School OPERATIONS Plant Focus Distribution Fleet Graphics Award Supplier News PRODUCTS New Products Product Poll New Product Submission Form DIRECTORIES Annual Manual eBook Take a Tour Contract Packaging Guide MORE White Papers Market Insights Market Research Store Classifieds Events Polls The Beverage Forum BevOps Fleet Summit Sponsor Insights MEDIA Videos Image Galleries Podcast Interactive Product Spotlights Webinars Sign In Create Account Sign Out My Account Home » 2021 State of the Industry: Tea’s versatility, healthfulness appeals to the masses Tea and Coffee 2021 State of the Industry: Tea’s versatility, healthfulness appeals to the masses Four in five consumers drinking tea, Tea Association says In June, Bigelow added to its portfolio of bagged teas featuring 100% of the recommended daily value of vitamin C, giving consumer a simple and delicious way to help the body’s defenses. July 1, 2021 Barbara Harfmann KEYWORDS Bagged tea / health and wellness / herbal teas / Ready-to-Drink Tea Order Reprints No Comments On any given day, more than 159 million Americans are consuming and enjoying refreshing, flavorful, functional tea. In fact, four in five of consumers drink tea, further cementing its status as a go-to beverage for the masses, states the Tea Association of the USA, New York. Because of its popularity and healthy attributes, the tea and ready-to-drink tea category is hitting all the right notes as it offers a multitude of options for every style and taste, including bagged, bottled, loose-leaf, hot, iced and cold brew.
From a much smaller base, kombucha post-fermented teas didn’t fare as well with a 25.8% deceleration , while single-cup tea posted sales of nearly $77 million, a 7.7% decline. However, some brands continued to shine bright, including Better Booch with triple-digit growth of 183.3% and Celestial Seasonings, which posted growth of 63.3% and sales of $5 million.
In addition to RTD teas brewed with yerba mate, other tea styles include herbal, fruit, white, chai, oolong, rooibos and kombucha, along with hard tea varietals. According to “The Tea Enthusiast’s Handbook: A Guide to the World’s Best Teas,” there are more than 20,000 different teas in the world.
Within the $1.5 billion packaged tea segment that experienced 7.9% growth, black teas were No. 1 with $639 million in dollar sales and a 2. do green tea helps in weight loss 8

What Is Milk Tea Benefits, milk tea article Uses, & Recipes

The addition of milk to tea results in a less astringent , less bitter flavor. This is because milk binds to some of the bitter chemical compounds found in tea while covering up some of the flavors of the tea. Some teas, such as strong black tea and Assam teas from India, are almost always served with milk to reduce the bitterness. Assam milk tea also makes a regular appearance as a British afternoon tea.
When it comes to milk tea recipes, some use quite a bit of milk. For instance, homemade masala chai requires equal parts of milk and water.​
There are many variations of milk tea, both hot and cold. Several types include a variety of spices as well as sugar.
button button The Spruce Eats What Is Milk Tea? Search Clear Recipe Page Search Pin Share Email View Saved Recipes button Search Clear Search Recipes by Course Breakfast & Brunch Lunch Appetizers & Snacks Dinner Desserts Side Dishes Breads See all Drinks & Cocktails Cocktail Recipes Shots & Shooters All About Beer All About Wine Teas Coffee Smoothies & Juices See all By Region American Food Asian Food European Food Latin American Food Middle Eastern Food African Food Australian Food See all Popular Ingredients Chicken Recipes Beef Recipes Pork Recipes Fish & Seafood Fruit & Veggie Recipes Cheese Recipes See all Occasions Back to School Snack Time Camping Fall Recipes We Want Candy Seasonal Produce See all How-Tos Learning How to Cook Cooking Techniques & Tips Cooking Equipment Knife Skills Ingredients What to Buy See all What to Buy Cookbooks Glassware & Drinkware Gifts Food Storage & Organization See all About Us Editorial Guidelines Anti-Racism Pledge Newsletter Contact Us Follow us: Instagram Pinterest Facebook YouTube Culinary Glossary Teas American Food What Is Milk Tea? Uses, Storage & Recipes By Lindsey Goodwin Lindsey Goodwin Instagram Twitter Website Lindsey Goodwin is a food writer and tea consultant with more than 12 years of experience exploring tea production and culture. Learn about The Spruce Eats’ Editorial Process Updated on 07/19/21 The Spruce
Premade milk tea can be purchased online or in specialty Asian markets. Look for “royal milk tea” which is sold either in cans or in packets as an “instant” form made with powdered milk. Black milk tea powder is also available and is the same type of ingredient that is used in bubble tea shops. Powders and cans can be stored in the pantry.
However, some of the tea’s bitter compounds are very beneficial to health, so if you’re drinking tea for health reasons, tea without milk is a better choice.
There are many regions in the world where milk tea is the default type of tea . This is most apparent in certain parts of India where tea usually refers to milk tea. Tea without milk is ordered as “black tea” or simply “tea without.” Milk tea is also commonly consumed in England, Ireland, Scotland, Canada, Sri Lanka, and Hong Kong.
Milk tea goes beyond simply adding a splash of milk to a cup of tea. There are many milk tea recipes found around the world, particularly Asia.
Black tea is also one of the healthiest types of tea you can drink. It contains antioxidants that support overall health and help lower the risk of chronic disease. It also has polyphenols and antimicrobial properties that are beneficial to the digestive system; milk tea article polyphenols may also help fight cancer cells. Black tea has also been shown to reduce stress and increase energy.

Milk tea, quite simply, is tea with milk added. This creates a smoother flavor and slightly sweetens the tea. It is a popular way to serve tea in many parts of the world, and it is an easy way to change up your average cup of tea.​
The amount of caffeine in milk tea is dependent on the type of tea used in the drink, which often is a type of black tea. Per 8-ounce cup, chai tea ranges from 60 to 120 milligrams of caffeine, while Assam black tea comes in at 80 milligrams and Darjeeling tea at 50 milligrams. It is safe to assume, though, that adding milk to a cup of tea means that the amount of actual tea consumed is less, thus lowering caffeine intake.
The term “milk tea” refers to any tea drink with milk added. It can be as simple as a splash of milk in a hot cup of tea, or it can be a complex recipe including various ingredients, like the popular bubble tea. Adding milk mellows and smooths out the flavors of tea, particularly some of the bitter notes found in black tea. Milk tea is enjoyed throughout the world as both a hot and cold beverage.
There are really no set guidelines or suggestions about how much milk to add to any particular tea. Most tea should not require a lot of milk, but it depends more than anything on personal taste and the type of tea brewed. In general, begin with a splash or a tablespoon of milk. Stir and taste the tea; if needed, add more until it is to the desired taste.
Milk has several health benefits as it contains nine essential nutrients including calcium, vitamin D, protein, vitamin B12, and potassium. Because it is packed with vitamins and minerals, only a small amount of milk is necessary to reap the benefits.
What Is Milk Tea Benefits, milk tea article Uses, & RecipesWhat Is Milk Tea Benefits, milk tea article Uses, & Recipes
But milk tea is also a term for hot and cold drink recipes that combine tea with a form of milk as well as a variety of spices. Certain countries have their own traditional versions of these recipes, which have gained popularity in America.
Many milk teas work well with a dairy substitute such as soy, almond, or rice milk. Coconut milk is not as versatile, but when combined with the right tea, it makes for a tasty beverage. tea tree oil scholarly articles

What Is Milk Tea Benefits, Uses, milk tea articles & Recipes

There are many variations of milk tea, both hot and cold. Several types include a variety of spices as well as sugar.
The addition of milk to tea results in a less astringent , less bitter flavor. This is because milk binds to some of the bitter chemical compounds found in tea while covering up some of the flavors of the tea. Some teas, such as strong black tea and Assam teas from India, are almost always served with milk to reduce the bitterness. Assam milk tea also makes a regular appearance as a British afternoon tea.
Milk has several health benefits as it contains nine essential nutrients including calcium, vitamin D, protein, vitamin B12, and potassium. Because it is packed with vitamins and minerals, only a small amount of milk is necessary to reap the benefits.
There are really no set guidelines or suggestions about how much milk to add to any particular tea. Most tea should not require a lot of milk, but it depends more than anything on personal taste and the type of tea brewed. In general, begin with a splash or a tablespoon of milk. Stir and taste the tea; if needed, add more until it is to the desired taste.
What Is Milk Tea Benefits, Uses, milk tea articles & RecipesWhat Is Milk Tea Benefits, Uses, milk tea articles & Recipes
Although milk tea can be made with a few different varieties of tea, black tea is one of the most common.
Milk tea goes beyond simply adding a splash of milk to a cup of tea. There are many milk tea recipes found around the world, particularly Asia.
When it comes to milk tea recipes, some use quite a bit of milk. For instance, homemade masala chai requires equal parts of milk and water.​
But milk tea is also a term for hot and cold drink recipes that combine tea with a form of milk as well as a variety of spices. Certain countries have their own traditional versions of these recipes, which have gained popularity in America.
The amount of caffeine in milk tea is dependent on the type of tea used in the drink, which often is a type of black tea. Per 8-ounce cup, chai tea ranges from 60 to 120 milligrams of caffeine, while Assam black tea comes in at 80 milligrams and Darjeeling tea at 50 milligrams. It is safe to assume, though, that adding milk to a cup of tea means that the amount of actual tea consumed is less, thus lowering caffeine intake.
However, some of the tea’s bitter compounds are very beneficial to health, so if you’re drinking tea for health reasons, tea without milk is a better choice. milk tea articles
The term “milk tea” refers to any tea drink with milk added. It can be as simple as a splash of milk in a hot cup of tea, or it can be a complex recipe including various ingredients, like the popular bubble tea. Adding milk mellows and smooths out the flavors of tea, particularly some of the bitter notes found in black tea. Milk tea is enjoyed throughout the world as both a hot and cold beverage.
button button The Spruce Eats What Is Milk Tea? Search Clear Recipe Page Search Pin Share Email View Saved Recipes button Search Clear Search Recipes by Course Breakfast & Brunch Lunch Appetizers & Snacks Dinner Desserts Side Dishes Breads See all Drinks & Cocktails Cocktail Recipes Shots & Shooters All About Beer All About Wine Teas Coffee Smoothies & Juices See all By Region American Food Asian Food European Food Latin American Food Middle Eastern Food African Food Australian Food See all Popular Ingredients Chicken Recipes Beef Recipes Pork Recipes Fish & Seafood Fruit & Veggie Recipes Cheese Recipes See all Occasions Back to School Snack Time Camping Fall Recipes We Want Candy Seasonal Produce See all How-Tos Learning How to Cook Cooking Techniques & Tips Cooking Equipment Knife Skills Ingredients What to Buy See all What to Buy Cookbooks Glassware & Drinkware Gifts Food Storage & Organization See all About Us Editorial Guidelines Anti-Racism Pledge Newsletter Contact Us Follow us: Instagram Pinterest Facebook YouTube Culinary Glossary Teas American Food What Is Milk Tea? Uses, Storage & Recipes By Lindsey Goodwin Lindsey Goodwin Instagram Twitter Website Lindsey Goodwin is a food writer and tea consultant with more than 12 years of experience exploring tea production and culture. Learn about The Spruce Eats’ Editorial Process Updated on 07/19/21 The Spruce
Premade milk tea can be purchased online or in specialty Asian markets. Look for “royal milk tea” which is sold either in cans or in packets as an “instant” form made with powdered milk. Black milk tea powder is also available and is the same type of ingredient that is used in bubble tea shops. Powders and cans can be stored in the pantry.
Black tea is also one of the healthiest types of tea you can drink. It contains antioxidants that support overall health and help lower the risk of chronic disease. It also has polyphenols and antimicrobial properties that are beneficial to the digestive system; polyphenols may also help fight cancer cells. Black tea has also been shown to reduce stress and increase energy.
Milk tea, quite simply, is tea with milk added. This creates a smoother flavor and slightly sweetens the tea. It is a popular way to serve tea in many parts of the world, and it is an easy way to change up your average cup of tea.​
There are many regions in the world where milk tea is the default type of tea . This is most apparent in certain parts of India where tea usually refers to milk tea. Tea without milk is ordered as “black tea” or simply “tea without.” Milk tea is also commonly consumed in England, Ireland, Scotland, Canada, Sri Lanka, and Hong Kong.
Many milk teas work well with a dairy substitute such as soy, almond, or rice milk. Coconut milk is not as versatile, tea articles 2020

How Bubble Tea Became a Complicated Symbol of Asian boba tea article

What was happening, says Wei, was that there was a generation of young Asian Americans — originally primarily Taiwanese Americans, but inclusive of Chinese, East Asian, and other members of the Asian diaspora in the Valley near Los Angeles — who grew up hanging out every day in boba shops, where they studied, gossiped with friends, and went on first dates, all over the cold, milky, tapioca ball-filled drink that is depending on where you’re from ).
“Because I look a little more ambiguous, to prove my Asianness, I need to adopt the mainstream Asian culture that people know as Asian: drinking bubble tea, eating certain foods, using chopsticks,” Giarrano says. Those practices help her feel more Asian American, letting her take part in a larger experience and community through something like bubble tea. “I definitely do like these things, but I can’t divorce it from knowing that these things are seen as Asian, so that’s probably, subconsciously, why I love these things as much as I do.”
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Here, bubble tea, as in the material world of boba shops, is more than just a drink. Like other alimentary items that have become tokens of Asian-American popular culture — rice, dumplings, pho, soy sauce, Korean barbecue — it’s an identity. And that, of course, comes with its own complications.
For Phil Wang, co-founder of Wong Fu Productions — one of the original trailblazers of Asian-American YouTubers — and co-owner of the bubble tea-serving cafe Bopomofo Cafe in the San Gabriel Valley, having that space was important. In high school, he would drive 30 minutes from his home near Oakland to the closest boba shop at UC Berkeley. Throughout most of college, he worked at a boba shop, where he would wait for his friends to come hang out. After graduating, he moved to the San Gabriel Valley and often worked on early Wong Fu scripts in boba shops.
That lack of visibility is often compounded for Asian Americans of non-East Asian descent. For Alana Giarrano, a 23-year-old college student with an Italian dad and a mom who is Lao and Vietnamese, bubble tea is both a salve for and a reminder of how she frequently feels “invisible” in Asian-American spaces, including her school’s student organizations.
Andrew Yang and his embrace of contentious model-minority stereotypes are boba liberalism. So is rallying around representation in Hollywood only insofar as it affects what we see on our screens. Tolerating an abhorrent, morally bankrupt presidency as long as it guarantees lower tax rates, stable housing prices, likelier admission to Ivy Leagues, and the promise of the American dream our immigrant parents had aspired to so long ago: boba liberalism. In Redmond’s words : “All sugar, no substance.”
Many of those immigrants settled in and had families in California — around LA, in particular — giving the state the largest number of Taiwanese immigrants in the U.S. in 2008. It was in those enclaves that boba culture took root in the early ’90s, introduced to young Taiwanese Americans by their families in Taiwan, and in turn introduced by those young Taiwanese Americans to other Asian Americans in their schools, neighborhoods, and social circles.
But mere representation and a shrinking distance between Asian Americans and mainstream white respectability isn’t a substitute for meaningful politics. Therein lies the danger of conflating food and identity in a mass culture of consumption and commodification. “Within commodity culture, ethnicity becomes spice, seasoning that can liven up the dull dish that is mainstream white culture,” bell hooks writes in her essay “ Eating the Other .” The commodification of difference, according to hooks, threatens to flatten and cannibalize the difference while stripping it of all historical context and political meaning. “As signs, their power to ignite critical consciousness is diffused when they are commodified. Communities of resistance are replaced by communities of consumption,” hooks writes.
There is something irredeemably maddening about tying so much of one’s cultural identity to an object of commodified desires, as young Asian Americans have done with bubble tea over the decades. But the thing about identity, as Hall points out, is that it can be just as much about “becoming” as about “being”; identity is who we were, who we are, and who we will become. Now is as critical a time as ever — culturally, politically, morally — to consider the image of ourselves that we want to construct, using our shared language and iconography. It matters how we choose to identify ourselves. It matters, in other words, how much substance we take with our sugar.
Those initial encounters with bubble tea in the LA area took place primarily in Taiwanese restaurants, served as an afterthought: “sweet tea in a thick Styrofoam cup, mixed with non-dairy creamer, ice and a spoonful of black tapioca pearls, which the staff kept in a bucket of syrup on the bottom shelf of a fridge,” Wei writes in her LA Weekly piece . In the late ’90s, the first dedicated local boba shop opened inside a food court in Arcadia; “by the early 2000s, a slew of shops dedicated to the beverage had opened. Ten Ren, Quickly, Tapioca Express, and Lollicup — all owned by immigrants of Taiwanese descent — were among the first businesses,” Wei wrote.
Home . It’s a fraught invocation when home is no longer the ancestral land from which we or our forebears departed. Nor is it the land where we have built our lives anew .
I can’t necessarily fault Asian Americana for doing so; as Mannur writes: “or Asian American cultural politics, the apparent conflation of food and ethnicity holds particular significance. For many consumers in mainstream America, food is often the only point of connection with racialized subjects, such as Asian Americans.”
“To me, bubble tea is linked to the economic and cultural power of East Asia, and Taiwan is a perfect locus of that,” Ray tells me. Young professionals — and students in particular — with roots in the Sinosphere are flooding urban American centers, and bringing with them a thirst for bubble tea, a beverage familiar to Americans in its apparent similarities to iced coffee, yet vastly foreign in the QQ texture of the tapioca pearls, and custom-made for the aesthetic-driven era of Instagram. These drinks, historian Chen points out, have not been adapted to American tastes; indeed, bubble tea in the U.S. follows Asian trends closely, as can be seen with the recent stateside imports of newer variations like cheese foam tea and .
Cultural identity is a matter of ‘becoming’ as well as of ‘being’. It belongs to the future as much as to the past. It is not something which already exists, transcending place, time, history and culture. Cultural identities come from somewhere, have histories. But, like everything which is historical, they undergo constant transformation. Far from being eternally fixed in some essentialised past, they are subject to the continuous ‘play’ of history, culture and power.
“As a Taiwanese-American kid growing up in the early 2000s in the San Gabriel Valley, the concoction was an integral part of my social life,” Wei writes in a 2017 LA Weekly article about how boba became synonymous with Asian-American youth culture in LA. Boba shops were, in her words, “our sacred gathering grounds.”
Unlike Wei, I didn’t grow up in a predominantly Asian community; from kindergarten through the end of high school, I was one of fewer than a dozen Asian Americans in my grade. It wasn’t until I got to college that I first laid eyes on bubble tea. The shop where I took my first sip, a place called Bubble Island just off of campus, soon became a centerpiece of my college life. Reflexively, as if to compensate for my 18 years surrounded by neighbors and classmates who didn’t share my background, I found nearly all my new friends in the university’s API student associations, which soon took up most of my extracurricular time. We would spend hours playing board games and chatting at Bubble Island. A couple years in, I could enter the store and, more often than not, spot someone I knew among the customers or working behind the counter. It felt like a kind of secret language for which only my Asian-American friends and I held the Rosetta Stone, a currency of exchange in a foreign landscape in which I otherwise felt lost and alone.
It’s : “thinking t-shirts, products, and merchandise are the main way of affirming one’s racial identity. It’s capitalist consumption presented as ‘API-ness.’ Buy more crazy rich asians tickets, sell more boba, go to raves, wear this brand. It’s reliant on capitalism.”
While bubble tea itself is neither inherently political nor bad, per se, some Asian Americans are critical of the dominant strain of Asian-American politics, called “boba liberalism,” that the drink has come to represent in certain circles. Boba liberalism — as defined by Twitter user @diaspora_is_red , said to be among the first to coin the term — is the “ substanceless trend-chasing spectacle ” that is mainstream Asian-American liberalism, derided as shallow, consumerist-capitalist, and robbed of meaning.
Yet despite the ways that bubble tea has been refashioned for a new age in global and American tastes, the young Asian Americans I spoke to all — deliberately or unconsciously — cited nostalgia as an inextricable force behind their affinity for boba.
But as fabricated as the cobbling together of “Asian American” was half a century ago , and as many “internal contradictions and slippages” as there are within that pan-ethnic coalition, in our fractured history, it has come to mean something: a thread of a shared experience; some semblance of aligned values; a “hard-earned unity,” in Lowe’s words.
Although there’s a persistent belief that East Asian populations don’t consume dairy due to widespread lactose intolerance, by the time of the Tang Dynasty in China, black tea was often drunk with butter, cream, milk , and other additives like salt and sesame, drawing from the practices of nomadic people in the north, Brown tells me.
It’s worth asking: Who gets to feel “unapologetically Asian”? When it comes to bubble tea’s outsized presence among the iconography of Asian-American pop culture and identity, the answer is, as is so often the case when talking about Asian-American issues, colored by an East Asian-American — and Chinese-American, in particular — hegemony that can erase or overshadow the experiences of other Asian Americans. Blockbuster rom-com Crazy Rich Asians , presidential candidate Andrew Yang , the groups and gaps glossed over by the model minority myth : There’s a tendency, when celebrating the accomplishments and milestones of Asian Americans, to be selectively forgetful of who counts as “Asian.”
The story of bubble tea is one of disparate parts coming together, a collision of cultural products and practices in one drink. Its origins date back much further than the last few decades, with historical roots in Middle-period China, according to Miranda Brown, a professor of Chinese studies at the University of Michigan.
How Bubble Tea Became a Complicated Symbol of Asian boba tea article
How Bubble Tea Became a Complicated Symbol of Asian boba tea article
Boba liberalism, as Redmond explains it, is “thinking the university key club and API student associations will lead the way in fighting for the dignity of the asian diaspora, in securing real material benefits to their communities, and rectifying the colonial crimes of the host country.”
“Bubble tea to me means home,” says Bhargava Chitti, 25, a medical student whose parents immigrated to New York from India in the ’80s. “It reminds me of home because I grew up drinking it in Flushing, and it’s emblematic of this abstract idea of home rooted in the Asian-American community and the global Asian diaspora at large. It’s given me home everywhere that I go.”
The new school of bubble tea shops , popularized by the success of chains like the San Francisco-born Boba Guys, which now has 15 locations, has ushered in a renewed consumer interest in bubble tea that started in the early to mid-2010s. Google Trends data shows a steady increase in interest over time for “bubble tea” and “boba tea” starting around 2012, with steeper inclines the past few years. The New York Times ran a trend story in 2017 about the swelling mainstream popularity of bubble tea . The number of venues listed as “bubble tea shop” on location-discovery app and technology platform Foursquare has more than tripled in the last four years, growing from 884 in September 2015 to 2,980 in September 2019, according to data provided by Foursquare. The global bubble tea market, valued at $1.9 billion by Allied Market Research in 2016, is projected to reach sales of $3.2 billion by 2023 .
Bubble tea is a gimmick, a meme, a stereotype, but it’s also a reference point for identity that generations of Asian Americans have used to cleave out their own place in the world, in ways both small and big, from eschewing Starbucks in favor of Boba Guys to opening a boba shop that can serve as a community gathering place. This is our lives.
While every culture has its own set of vital dishes and culinary traditions, it’s striking how much of the pantheon of symbols of Asian-American identity comprises food and drink. These icons, boba tea article from bubble tea to Pocky to ramen, are not just objects to consume, but also to wear and display , to trade as , to signify and perform a shared idea of identity.
“It’s a sweet, popular thing. It’s not very offensive,” @diaspora_is_red, identified using the name Redmond, says on the Asian-American publication Plan A Magazine ’s podcast, referring to both the drink and the politics. “But it’s also not that good for you from a health point of view. It’s just empty calories.”
From there, bubble tea made its way to the U.S. thanks to changing migration patterns, according to Yong Chen, a professor of history at UC Irvine and the author of Chop Suey, USA: The Story of Chinese Food in America . After Congress passed the Immigration and Nationality Act of 1965, which abolished the immigration policy that restricted the entry of Asians, Southern and Eastern Europeans, and members of other ethnic groups, waves of Taiwanese immigrants came to the U.S. from the ’60s through the ’90s.
Think of the stories, movies, and shows that we prize and canonize as landmark representations of our community: for example, the Netflix rom-com Always Be My Maybe , which promotes a tired myth of culinary authenticity in its plotline about a celebrity chef; and Crazy Rich Asians , which presents so many dazzling arrays of food that it’s torturous to sit through the film on an empty stomach. Lulu Wang’s The Farewell stands out among recent examples for its twisting of the oft-recited platitude that “food is love”; here, food is as much a burden as it is a source of joy, a rare departure from Asian-American narratives that typically fetishize the acts of cooking and eating.
For Asian Americans — whose history in this country is one of being treated as the perpetually foreign Other, meant to be both “integrated into the national political sphere” and “marginalized and returned to their alien origins,” as interdisciplinary scholar and Yale University professor Lisa Lowe writes in the book Immigrant Acts: On Asian American Cultural Politics — the promise of food as a universal language is impossibly tantalizing, and with each passing year seems more within reach than ever. Once-“exotic” dishes like xiao long bao , bún bò Huế , and sisig have become shorthand for the kind of worldliness and trendiness that non-Asian, urban-dwelling Americans aspire to. Bubble tea appears on major network television shows , not as a novelty, but as a normalized mainstay. There is, after so long, at least a growing visibility that gestures at some form of acceptance.
Bubble tea has been around in the U.S. since the ’90s, but it wasn’t until millions of people watched that YouTube video by Chinese-American brothers Andrew and David Fung that the phenomenon of “boba life” or “boba culture” was given a name, according to Clarissa Wei, a Hong Kong-based journalist who grew up in California’s Asian-American enclave of the San Gabriel Valley. “It was as if, for the first time, people were able to define what the subculture was,” Wei tells me. “Because before … no one knew how to describe what was happening.”
Bubble tea’s conjuring of home, then, works on two levels: a yearning for the imagined home denied to us by the diasporic condition, as well as a sense of nostalgia for the closest approximation — the boba shop, functioning as a “ third place ” in both the literal and figurative sense. Asian-American expressions of longing for the boba shops of one’s youth are not just about the physical space, or the drink, or the companionship; they’re as much about the time, however fleeting, spent within the bubble of comfort and belonging. It’s about missing the period of your life when you could afford to let bubble tea occupy such a large part of it.
“The truth is,” Wei writes for LA Weekly , “at a certain point, you graduate from boba life.”
The original form of bubble tea brought together disparate elements — Chinese tea, tapioca from South American cassava, American powdered creamer — into a Taiwanese whole, one that gained global purchase and entered the shared vocabulary of an entire diaspora of Asian Americans. The label “Asian American,” too, is an assemblage of different parts into one historically fraught grouping. It’s “not a natural or static category; it is a socially constructed unity, a situationally specific position, assumed for political reasons,” Lowe writes in Immigrant Acts .
Both these trends are illustrative of ongoing shifts in globalization, migration, and economic and cultural power. Much like the surge of a new type of Chinese restaurant in tandem with the upward mobility of wealthier, better-educated immigrants and visitors from China, Hong Kong, and Taiwan, the current renaissance of bubble tea is symptomatic of the emergence of East Asia as a global power, says Krishnendu Ray, associate professor of food studies at New York University and the author of the book The Ethnic Restaurateur , in which he writes that Chinese cuisine, after a history of being devalued in American estimation, is likely to ascend in the “ global hierarchy of taste ” if China’s economic rise continues.
“In some ways, it is a quintessential passing of the baton from American hegemony to East Asian hegemony,” Ray says. “It’s symptomatic of East Asia’s location — of East Asian urban culture — in the global circulation of taste.”
Janet Sung is a Korean-American illustrator born and raised in New York.
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This development has been , but it’s become clear, talking to professionals within the industry, that there’s another parallel even closer to home: the evolution of Chinese-American restaurants , which are increasingly being opened by college-educated Chinese Americans who grew up in the U.S. or moved here for school, and whose stylish, regionally specific restaurants are the product of choice, rather than the necessity that drove their parents’ generation.
This motif is, at its core, “food pornography,” writes Miami University associate professor Anita Mannur in a 2005 essay , in reference to Asian-American literary critic Sau-ling Cynthia Wong’s use of the term. “Defining it as an exploitative form of self-Orientalization in which Asian-American subjects actively promote the ‘exotic’ nature of their foodways, Wong argues that ‘in cultural terms translates to reifying perceived cultural differences and exaggerating one’s otherness in order to gain foothold in a white-dominated social system … superficially, food pornography appears to be a promotion, rather than a vitiation or devaluation, of one’s ethnic identity.”
And : “wanting to reconnect with your roots by drinking bubble tea, getting added to subtle asian traits, and organizing fundraisers for your asian student association, but never studying your history and feeling solidarity with your homeland against imperialism.”
Food is a tangible product, made for consumption; in more sentimental terms, it has been frequently described as a “ universal language ” that transcends borders or backgrounds. In the U.S., a land in which immigrant groups have lived in constant and varied states of assimilation, food is both a temporary portal to one’s point of origin and a potential path forward. “Food is the one thing right now, at least in Western culture, that if you’re really Asian or really authentic, it’s praised,” says Wang. “Food is something where we can truly be ourselves. And it’s like, you have to come into our world.”
If the first cups of boba sold in California two to three decades ago were merely $1 afterthoughts to accompany meals in Chinese restaurants, now the drinks are undisputedly the stars — less styrofoam and powdered non-dairy creamers, more fresh milk and ethically sourced tea leaves.
“Please remember that ’s not as big of a thing across East Asia as a whole,” Tom Yoo, a 27-year-old Korean American in New York, tells me in the Facebook group Subtle Asian Eats , a Subtle Asian Traits offshoot focused on food. “I’m really happy that Asian culture in any form is getting so much recognition these days,” Yoo later says over the phone. “But at the same time, I’m Korean, and sometimes I feel like Chinese culture drowns out Korean culture.”
While the Fung Brothers’ “Bobalife” music video has racked up more than 2.3 million views in the six and a half years it’s been up, not nearly as many people know that there’s a follow-up: “ ,” a tongue-in-cheek song that has been viewed only half a million times — the “indie” sequel, if you will. In the video, the Fungs satirize three genres of music, accompanied by the usual plethora of girls, bros, and Asian-American motifs. Among the lyrics, one set of lines stands out, unexpected in both its self-awareness and its pointedness: “Another boba song, don’t know how we did it. They say that these are gimmick songs, but tell me, how can this be wrong when this is just our lives?”
The first wave of boba shops in the San Gabriel Valley were also run by immigrant families, Wang points out, and so they had to cut costs and save money; it was more about survival than answering a calling. But now, in addition to the stores being brought to the U.S. by big brands in Asia — popular Taiwanese chain Tiger Sugar being one example — many of the new boba shops are opened by first- and second-generation Asian Americans. “They’re taking their Western influences and tastes, and they’re trying to adapt,” says Wang. “It’s going back to changing that narrative, where it’s not all the cheap stuff … It’s like, no, our communities are leveling up, too, and you should take us seriously.”
How bubble tea became far more than just a drink to young Asian Americans
“We’re livin’ the boba life,” the chorus repeats. Another lyric, at the close of the song, proclaims: “The new drink of young Asians … Call us the boba generation.”
Because eventually, for nearly everyone, there comes a time when life no longer revolves around the local boba shop. You grow up, you move out, you drift away from the things that you once thought made up the entire world. You stop worrying too much about how to belong, and start thinking about how to live.

“In fact, when Europeans first started showing up in China in the 17th century … they report drinking milk tea,” she says. Europeans took home the idea that tea had to be drunk with milk and salt or sugar, while the practice of adding dairy to tea eventually fell out of favor in China. When the colonial British returned to the country in the 19th century, they reintroduced milk tea back into the Chinese diet, as can be seen most clearly in former British colonies like Hong Kong, which has a tradition of milk tea made with condensed milk.
In his influential 1996 essay “ Cultural Identity and Diaspora ,” cultural theorist Stuart Hall writes of identity:
Boba culture isn’t limited to the San Gabriel Valley or the Midwestern campus where I surrounded myself with what I thought to be Asian Americana. It’s embedded in immigrant communities across California; in college towns dotting the country; in the steadily multiplying bubble tea shops that I walk past in New York. With the explosive growth of online communities like Subtle Asian Traits — the Asian diaspora-centric Facebook group that has accrued more than 1.5 million members little more than a year after it was created — the physical space is now supplemented by an intangible one. These online communities are border-transcending virtual bubble tea shops filled with an endless stream of memes, jokes, and confessions about boba, strict parents, and other markers of what is often imagined as the universal experience of children of Asian immigrants in the West.
Sean Marc Lee/Eater By the time tapioca starch, derived from the South American cassava plant, came to Taiwan via Southeast Asia during the colonial period, there was already a longstanding Chinese and Southeast Asian tradition of eating jelly-like starch desserts, such as sago pearls, in sweet soups. Tapioca balls, with their signature “Q” or “QQ” texture — the “ untranslatable bouncy, rubbery, chewy consistency … treasured in Taiwan,” earlier this year — fit right into the larger historical southern Chinese culinary landscape, according to Brown.
Those boba shops, as well as the drinks they served, were all about the same, Wei tells me: worn board games, Jay Chou ’s Taiwanese pop playing in the background, teens spending hours drinking bubble tea on cheap Ikea furniture, the Asian-American equivalent of a coffee shop. new york times boba article

How Bubble Tea Became a Complicated Symbol bubble tea article of Asian

It’s : “thinking t-shirts, products, and merchandise are the main way of affirming one’s racial identity. It’s capitalist consumption presented as ‘API-ness.’ Buy more crazy rich asians tickets, sell more boba, go to raves, wear this brand. It’s reliant on capitalism.”
But as fabricated as the cobbling together of “Asian American” was half a century ago , and as many “internal contradictions and slippages” as there are within that pan-ethnic coalition, in our fractured history, it has come to mean something: a thread of a shared experience; some semblance of aligned values; a “hard-earned unity,” in Lowe’s words.
“To me, bubble tea is linked to the economic and cultural power of East Asia, and Taiwan is a perfect locus of that,” Ray tells me. Young professionals — and students in particular — with roots in the Sinosphere are flooding urban American centers, and bringing with them a thirst for bubble tea, a beverage familiar to Americans in its apparent similarities to iced coffee, yet vastly foreign in the QQ texture of the tapioca pearls, and custom-made for the aesthetic-driven era of Instagram. These drinks, historian Chen points out, have not been adapted to American tastes; indeed, bubble tea in the U.S. follows Asian trends closely, as can be seen with the recent stateside imports of newer variations like cheese foam tea and .
Both these trends are illustrative of ongoing shifts in globalization, migration, and economic and cultural power. Much like the surge of a new type of Chinese restaurant in tandem with the upward mobility of wealthier, better-educated immigrants and visitors from China, Hong Kong, and Taiwan, the current renaissance of bubble tea is symptomatic of the emergence of East Asia as a global power, says Krishnendu Ray, associate professor of food studies at New York University and the author of the book The Ethnic Restaurateur , in which he writes that Chinese cuisine, after a history of being devalued in American estimation, is likely to ascend in the “ global hierarchy of taste ” if China’s economic rise continues.
For Asian Americans — whose history in this country is one of being treated as the perpetually foreign Other, meant to be both “integrated into the national political sphere” and “marginalized and returned to their alien origins,” as interdisciplinary scholar and Yale University professor Lisa Lowe writes in the book Immigrant Acts: On Asian American Cultural Politics — the promise of food as a universal language is impossibly tantalizing, and with each passing year seems more within reach than ever. Once-“exotic” dishes like xiao long bao , bún bò Huế , and sisig have become shorthand for the kind of worldliness and trendiness that non-Asian, urban-dwelling Americans aspire to. Bubble tea appears on major network television shows , not as a novelty, but as a normalized mainstay. There is, after so long, at least a growing visibility that gestures at some form of acceptance.
View this post on Instagram A post shared by subtle asian traits ® on Mar 3, 2019 at 4:25am PST

Here, bubble tea, as in the material world of boba shops, is more than just a drink. Like other alimentary items that have become tokens of Asian-American popular culture — rice, dumplings, pho, soy sauce, Korean barbecue — it’s an identity. And that, of course, comes with its own complications.
Because eventually, for nearly everyone, there comes a time when life no longer revolves around the local boba shop. You grow up, you move out, you drift away from the things that you once thought made up the entire world. You stop worrying too much about how to belong, and start thinking about how to live.
Andrew Yang and his embrace of contentious model-minority stereotypes are boba liberalism. So is rallying around representation in Hollywood only insofar as it affects what we see on our screens. Tolerating an abhorrent, morally bankrupt presidency as long as it guarantees lower tax rates, stable housing prices, likelier admission to Ivy Leagues, and the promise of the American dream our immigrant parents had aspired to so long ago: boba liberalism. In Redmond’s words : “All sugar, no substance.”
Cultural identity is a matter of ‘becoming’ as well as of ‘being’. It belongs to the future as much as to the past. It is not something which already exists, transcending place, time, history and culture. Cultural identities come from somewhere, have histories. But, like everything which is historical, they undergo constant transformation. Far from being eternally fixed in some essentialised past, they are subject to the continuous ‘play’ of history, culture and power.
The original form of bubble tea brought together disparate elements — Chinese tea, tapioca from South American cassava, American powdered creamer — into a Taiwanese whole, one that gained global purchase and entered the shared vocabulary of an entire diaspora of Asian Americans. The label “Asian American,” too, is an assemblage of different parts into one historically fraught grouping. It’s “not a natural or static category; it is a socially constructed unity, a situationally specific position, assumed for political reasons,” Lowe writes in Immigrant Acts .
Bubble tea has been around in the U.S. since the ’90s, but it wasn’t until millions of people watched that YouTube video by Chinese-American brothers Andrew and David Fung that the phenomenon of “boba life” or “boba culture” was given a name, according to Clarissa Wei, a Hong Kong-based journalist who grew up in California’s Asian-American enclave of the San Gabriel Valley. “It was as if, for the first time, people were able to define what the subculture was,” Wei tells me. “Because before … no one knew how to describe what was happening.”
“As a Taiwanese-American kid growing up in the early 2000s in the San Gabriel Valley, the concoction was an integral part of my social life,” Wei writes in a 2017 LA Weekly article about how boba became synonymous with Asian-American youth culture in LA. Boba shops were, in her words, “our sacred gathering grounds.”
I can’t necessarily fault Asian Americana for doing so; as Mannur writes: “or Asian American cultural politics, the apparent conflation of food and ethnicity holds particular significance. For many consumers in mainstream America, food is often the only point of connection with racialized subjects, such as Asian Americans.”
There is something irredeemably maddening about tying so much of one’s cultural identity to an object of commodified desires, as young Asian Americans have done with bubble tea over the decades. But the thing about identity, as Hall points out, is that it can be just as much about “becoming” as about “being”; identity is who we were, who we are, and who we will become. Now is as critical a time as ever — culturally, politically, morally — to consider the image of ourselves that we want to construct, using our shared language and iconography. It matters how we choose to identify ourselves. It matters, in other words, how much substance we take with our sugar.
Many of those immigrants settled in and had families in California — around LA, in particular — giving the state the largest number of Taiwanese immigrants in the U.S. in 2008. It was in those enclaves that boba culture took root in the early ’90s, introduced to young Taiwanese Americans by their families in Taiwan, and in turn introduced by those young Taiwanese Americans to other Asian Americans in their schools, neighborhoods, and social circles.
Although there’s a persistent belief that East Asian populations don’t consume dairy due to widespread lactose intolerance, by the time of the Tang Dynasty in China, black tea was often drunk with butter, cream, milk , and other additives like salt and sesame, drawing from the practices of nomadic people in the north, Brown tells me.
But mere representation and a shrinking distance between Asian Americans and mainstream white respectability isn’t a substitute for meaningful politics. Therein lies the danger of conflating food and identity in a mass culture of consumption and commodification. “Within commodity culture, ethnicity becomes spice, seasoning that can liven up the dull dish that is mainstream white culture,” bell hooks writes in her essay “ Eating the Other .” The commodification of difference, according to hooks, threatens to flatten and cannibalize the difference while stripping it of all historical context and political meaning. “As signs, their power to ignite critical consciousness is diffused when they are commodified. Communities of resistance are replaced by communities of consumption,” hooks writes.
How bubble tea became far more than just a drink to young Asian Americans
Home . It’s a fraught invocation when home is no longer the ancestral land from which we or our forebears departed. Nor is it the land where we have built our lives anew .
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How Bubble Tea Became a Complicated Symbol bubble tea article of Asian
How Bubble Tea Became a Complicated Symbol bubble tea article of Asian
“It’s a sweet, popular thing. It’s not very offensive,” @diaspora_is_red, identified using the name Redmond, says on the Asian-American publication Plan A Magazine ’s podcast, referring to both the drink and the politics. “But it’s also not that good for you from a health point of view. It’s just empty calories.”
Unlike Wei, I didn’t grow up in a predominantly Asian community; from kindergarten through the end of high school, I was one of fewer than a dozen Asian Americans in my grade. It wasn’t until I got to college that I first laid eyes on bubble tea. The shop where I took my first sip, a place called Bubble Island just off of campus, soon became a centerpiece of my college life. Reflexively, as if to compensate for my 18 years surrounded by neighbors and classmates who didn’t share my background, I found nearly all my new friends in the university’s API student associations, which soon took up most of my extracurricular time. We would spend hours playing board games and chatting at Bubble Island. A couple years in, I could enter the store and, more often than not, spot someone I knew among the customers or working behind the counter. It felt like a kind of secret language for which only my Asian-American friends and I held the Rosetta Stone, a currency of exchange in a foreign landscape in which I otherwise felt lost and alone.
Think of the stories, movies, and shows that we prize and canonize as landmark representations of our community: for example, the Netflix rom-com Always Be My Maybe , which promotes a tired myth of culinary authenticity in its plotline about a celebrity chef; and Crazy Rich Asians , which presents so many dazzling arrays of food that it’s torturous to sit through the film on an empty stomach. Lulu Wang’s The Farewell stands out among recent examples for its twisting of the oft-recited platitude that “food is love”; here, food is as much a burden as it is a source of joy, a rare departure from Asian-American narratives that typically fetishize the acts of cooking and eating.
Bubble tea is a gimmick, a meme, a stereotype, but it’s also a reference point for identity that generations of Asian Americans have used to cleave out their own place in the world, in ways both small and big, from eschewing Starbucks in favor of Boba Guys to opening a boba shop that can serve as a community gathering place. This is our lives.
“We’re livin’ the boba life,” the chorus repeats. Another lyric, at the close of the song, proclaims: “The new drink of young Asians … Call us the boba generation.”
While bubble tea itself is neither inherently political nor bad, per se, some Asian Americans are critical of the dominant strain of Asian-American politics, called “boba liberalism,” that the drink has come to represent in certain circles. Boba liberalism — as defined by Twitter user @diaspora_is_red , said to be among the first to coin the term — is the “ substanceless trend-chasing spectacle ” that is mainstream Asian-American liberalism, derided as shallow, consumerist-capitalist, and robbed of meaning.
Those boba shops, as well as the drinks they served, were all about the same, Wei tells me: worn board games, Jay Chou ’s Taiwanese pop playing in the background, teens spending hours drinking bubble tea on cheap Ikea furniture, the Asian-American equivalent of a coffee shop. It was about the physical space and what it facilitated — friendship, familiarity, the feeling of belonging — more than the drink itself, Wei says.
In his influential 1996 essay “ Cultural Identity and Diaspora ,” cultural theorist Stuart Hall writes of identity:
“Bubble tea to me means home,” says Bhargava Chitti, 25, a medical student whose parents immigrated to New York from India in the ’80s. bubble tea article “It reminds me of home because I grew up drinking it in Flushing, and it’s emblematic of this abstract idea of home rooted in the Asian-American community and the global Asian diaspora at large. It’s given me home everywhere that I go.”
While every culture has its own set of vital dishes and culinary traditions, it’s striking how much of the pantheon of symbols of Asian-American identity comprises food and drink. These icons, from bubble tea to Pocky to ramen, are not just objects to consume, but also to wear and display , to trade as , to signify and perform a shared idea of identity.
While the Fung Brothers’ “Bobalife” music video has racked up more than 2.3 million views in the six and a half years it’s been up, not nearly as many people know that there’s a follow-up: “ ,” a tongue-in-cheek song that has been viewed only half a million times — the “indie” sequel, if you will. In the video, the Fungs satirize three genres of music, accompanied by the usual plethora of girls, bros, and Asian-American motifs. Among the lyrics, one set of lines stands out, unexpected in both its self-awareness and its pointedness: “Another boba song, don’t know how we did it. They say that these are gimmick songs, but tell me, how can this be wrong when this is just our lives?”
Bubble tea’s conjuring of home, then, works on two levels: a yearning for the imagined home denied to us by the diasporic condition, as well as a sense of nostalgia for the closest approximation — the boba shop, functioning as a “ third place ” in both the literal and figurative sense. Asian-American expressions of longing for the boba shops of one’s youth are not just about the physical space, or the drink, or the companionship; they’re as much about the time, however fleeting, spent within the bubble of comfort and belonging. It’s about missing the period of your life when you could afford to let bubble tea occupy such a large part of it.
Sean Marc Lee/Eater By the time tapioca starch, derived from the South American cassava plant, came to Taiwan via Southeast Asia during the colonial period, there was already a longstanding Chinese and Southeast Asian tradition of eating jelly-like starch desserts, such as sago pearls, in sweet soups. Tapioca balls, with their signature “Q” or “QQ” texture — the “ untranslatable bouncy, rubbery, chewy consistency … treasured in Taiwan,” earlier this year — fit right into the larger historical southern Chinese culinary landscape, according to Brown.
What was happening, says Wei, was that there was a generation of young Asian Americans — originally primarily Taiwanese Americans, but inclusive of Chinese, East Asian, and other members of the Asian diaspora in the Valley near Los Angeles — who grew up hanging out every day in boba shops, where they studied, gossiped with friends, and went on first dates, all over the cold, milky, tapioca ball-filled drink that is depending on where you’re from ).
Boba culture isn’t limited to the San Gabriel Valley or the Midwestern campus where I surrounded myself with what I thought to be Asian Americana. It’s embedded in immigrant communities across California; in college towns dotting the country; in the steadily multiplying bubble tea shops that I walk past in New York. With the explosive growth of online communities like Subtle Asian Traits — the Asian diaspora-centric Facebook group that has accrued more than 1.5 million members little more than a year after it was created — the physical space is now supplemented by an intangible one. These online communities are border-transcending virtual bubble tea shops filled with an endless stream of memes, jokes, and confessions about boba, strict parents, and other markers of what is often imagined as the universal experience of children of Asian immigrants in the West.
The story of bubble tea is one of disparate parts coming together, a collision of cultural products and practices in one drink. Its origins date back much further than the last few decades, with historical roots in Middle-period China, according to Miranda Brown, a professor of Chinese studies at the University of Michigan.
That lack of visibility is often compounded for Asian Americans of non-East Asian descent. For Alana Giarrano, a 23-year-old college student with an Italian dad and a mom who is Lao and Vietnamese, bubble tea is both a salve for and a reminder of how she frequently feels “invisible” in Asian-American spaces, including her school’s student organizations.
And : “wanting to reconnect with your roots by drinking bubble tea, getting added to subtle asian traits, and organizing fundraisers for your asian student association, but never studying your history and feeling solidarity with your homeland against imperialism.”
This development has been , but it’s become clear, talking to professionals within the industry, that there’s another parallel even closer to home: the evolution of Chinese-American restaurants , which are increasingly being opened by college-educated Chinese Americans who grew up in the U.S. or moved here for school, and whose stylish, regionally specific restaurants are the product of choice, rather than the necessity that drove their parents’ generation.
This motif is, at its core, “food pornography,” writes Miami University associate professor Anita Mannur in a 2005 essay , in reference to Asian-American literary critic Sau-ling Cynthia Wong’s use of the term. “Defining it as an exploitative form of self-Orientalization in which Asian-American subjects actively promote the ‘exotic’ nature of their foodways, Wong argues that ‘in cultural terms translates to reifying perceived cultural differences and exaggerating one’s otherness in order to gain foothold in a white-dominated social system … superficially, food pornography appears to be a promotion, rather than a vitiation or devaluation, of one’s ethnic identity.”
Boba liberalism, as Redmond explains it, is “thinking the university key club and API student associations will lead the way in fighting for the dignity of the asian diaspora, in securing real material benefits to their communities, and rectifying the colonial crimes of the host country.”
The first wave of boba shops in the San Gabriel Valley were also run by immigrant families, Wang points out, and so they had to cut costs and save money; it was more about survival than answering a calling. But now, in addition to the stores being brought to the U.S. by big brands in Asia — popular Taiwanese chain Tiger Sugar being one example — many of the new boba shops are opened by first- and second-generation Asian Americans. “They’re taking their Western influences and tastes, and they’re trying to adapt,” says Wang. “It’s going back to changing that narrative, where it’s not all the cheap stuff … It’s like, no, our communities are leveling up, too, and you should take us seriously.”
“The truth is,” Wei writes for LA Weekly , “at a certain point, you graduate from boba life.”
It’s worth asking: Who gets to feel “unapologetically Asian”? When it comes to bubble tea’s outsized presence among the iconography of Asian-American pop culture and identity, the answer is, as is so often the case when talking about Asian-American issues, colored by an East Asian-American — and Chinese-American, in particular — hegemony that can erase or overshadow the experiences of other Asian Americans. Blockbuster rom-com Crazy Rich Asians , presidential candidate Andrew Yang , the groups and gaps glossed over by the model minority myth : There’s a tendency, when celebrating the accomplishments and milestones of Asian Americans, to be selectively forgetful of who counts as “Asian.”
From there, bubble tea made its way to the U.S. thanks to changing migration patterns, according to Yong Chen, a professor of history at UC Irvine and the author of Chop Suey, USA: The Story of Chinese Food in America . After Congress passed the Immigration and Nationality Act of 1965, which abolished the immigration policy that restricted the entry of Asians, Southern and Eastern Europeans, and members of other ethnic groups, waves of Taiwanese immigrants came to the U.S. from the ’60s through the ’90s.
Janet Sung is a Korean-American illustrator born and raised in New York.
The new school of bubble tea shops , popularized by the success of chains like the San Francisco-born Boba Guys, which now has 15 locations, has ushered in a renewed consumer interest in bubble tea that started in the early to mid-2010s. Google Trends data shows a steady increase in interest over time for “bubble tea” and “boba tea” starting around 2012, with steeper inclines the past few years. The New York Times ran a trend story in 2017 about the swelling mainstream popularity of bubble tea . The number of venues listed as “bubble tea shop” on location-discovery app and technology platform Foursquare has more than tripled in the last four years, growing from 884 in September 2015 to 2,980 in September 2019, according to data provided by Foursquare. The global bubble tea market, valued at $1.9 billion by Allied Market Research in 2016, is projected to reach sales of $3.2 billion by 2023 .
“Back then, it was about having something cheap, affordable, kind of decent,” Oscar Ho, 25, tells me, reminiscing about how his family would make the trip from San Diego to LA to buy Asian groceries, eat Chinese food, and drink bubble tea when he was a kid. “But I feel like that generation has grown up and took it upon themselves to improve on that … More newer places, unique places, places more focused on quality and certain ingredients emerged.”
Food is a tangible product, made for consumption; in more sentimental terms, it has been frequently described as a “ universal language ” that transcends borders or backgrounds. In the U.S., a land in which immigrant groups have lived in constant and varied states of assimilation, food is both a temporary portal to one’s point of origin and a potential path forward. “Food is the one thing right now, at least in Western culture, that if you’re really Asian or really authentic, it’s praised,” says Wang. “Food is something where we can truly be ourselves. And it’s like, you have to come into our world.”
Those initial encounters with bubble tea in the LA area took place primarily in Taiwanese restaurants, served as an afterthought: “sweet tea in a thick Styrofoam cup, mixed with non-dairy creamer, ice and a spoonful of black tapioca pearls, which the staff kept in a bucket of syrup on the bottom shelf of a fridge,” Wei writes in her LA Weekly piece . In the late ’90s, the first dedicated local boba shop opened inside a food court in Arcadia; “by the early 2000s, a slew of shops dedicated to the beverage had opened. Ten Ren, Quickly, Tapioca Express, and Lollicup — all owned by immigrants of Taiwanese descent — were among the first businesses,” Wei wrote.
If the first cups of boba sold in California two to three decades ago were merely $1 afterthoughts to accompany meals in Chinese restaurants, now the drinks are undisputedly the stars — less styrofoam and powdered non-dairy creamers, more fresh milk and ethically sourced tea leaves.
“Please remember that ’s not as big of a thing across East Asia as a whole,” Tom Yoo, a 27-year-old Korean American in New York, tells me in the Facebook group Subtle Asian Eats , a Subtle Asian Traits offshoot focused on food. “I’m really happy that Asian culture in any form is getting so much recognition these days,” Yoo later says over the phone. “But at the same time, I’m Korean, and sometimes I feel like Chinese culture drowns out Korean culture.”
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The fusion of those two traditions — milk tea and chewy, gelatinous pearls — eventually gave rise to bubble tea. Milk tea, typically made with powdered creamer introduced in Taiwan by American foreign aid programs during the Cold War , was a “favorite local drink” prior to the 1980s, as Nguyen-Okwu reports. According to one of multiple competing origin stories , Liu Han-chieh, the owner of Taichung tea shop Chun Shui Tang, came up with the idea of milk tea chilled with ice in the early ’80s after seeing coffee served cold in Japan. The “bubble” in “bubble tea” refers to “the thick layer of foam that forms on top of the drink after it is shaken” in a cocktail shaker, per the South China Morning Post . The addition of large tapioca pearls, nicknamed “boba” in reference to the busty assets of Hong Kong actress and sex symbol Amy Yip, came in the late ’80s when a Chen Shui Tang staff member, Lin Hsiu Hui, poured fen yuan tapioca balls into her iced Assam tea, . why green tea lose weight

Beneficial effects of green tea A green tea articles literature review

A double-blind, placebo-controlled, cross-over design study showed that consumption of a beverage containing green tea catechins, caffeine, and calcium increases 24-h energy expenditure by 4.6%, but the contribution of the individual ingredients could not be distinguished. It was suggested that such modifications were sufficient to prevent weight gain. It has been reported that the body weights of rats and their plasma triglyceride, cholesterol, and low-density lipoprotein cholesterol were significantly reduced by feedings of Oolong, black, and green tea leaves to the animals. In addition, the inhibition of growth and suppression of lipogenesis in MCF-7 breast cancer cells may be through down-regulation of fatty acid synthase gene expression in the nucleus and stimulation of cell energy expenditure in the mitochondria . When fed to mice, EGCG purified from green tea decreased diet-induced obesity in mice by decreasing energy absorption and increasing fat oxidation . The increased and prolonged sympathetic stimulation of thermogenesis by the interaction between polyphenols and caffeine could be of value in assisting the management of obesity .
Long-term ingestion of green tea increases UDP-glucuronosyl transferase activity in rats , and after being absorbed, catechins are metabolized by drug-metabolizing enzymes in various organs . Thus, the increased glucuronidation through UDP-glucuronosyl transferase induction is postulated to contribute to the anticarcinogenic effect of green tea by facilitating the metabolism of chemical carcinogens into inactive products that are readily excreted. The interaction between 2-amino-3-methylimidazol quinoline and green tea catechin metabolism was examined . IQ is a precarcinogen that was originally detected in an extract of fried meat. The major route of IQ biotransformation in rats is cytochrome P450 in the first step, followed by conjugation to a sulfate and a glucuronide conjugate. Green tea modifies IQ metabolism in rats, increasing the formation of IQ glucuronides, which are then excreted in the urine. Moreover, protection against cancers induced by polycyclic aromatic hydrocarbons by green tea catechins may be due to the inhibition of their cytochrome P450 metabolism, but the effect of green tea on cytochrome P450 enzymes depends on the particular form. The long-term consumption of green tea increases cytochrome P450 1A1 and 1A2 activities, but not 2B1 and 2E1 activities, in normal rats. However, it is difficult to draw conclusions about a beneficial effect of green tea against carcinogens involving only modulation of this metabolic pathway.
Green tea is a popular neutraceutical as an antioxidant. Antioxidants are compounds that protect cells against the damaging effects of reactive oxygen species, such as singlet oxygen, superoxide, peroxyl radicals, hydroxyl radicals, and peroxynitrite. An imbalance between antioxidants and reactive oxygen species results in oxidative stress, leading to cellular damage . Catechins are hypothesized to help protect against these diseases by contributing, along with antioxidant vitamins and enzymes , to the total antioxidant defense system .
§ Especially thearubigins and theaflavins
Green tea consumption has also been linked to the prevention of many types of cancer, including lung, colon, esophagus, mouth, stomach, small intestine, kidney, pancreas, and mammary glands . Several epidemiological studies and clinical trials showed that green tea may reduce the risk of many chronic diseases . This beneficial effect has been attributed to the presence of high amounts of polyphenols, which are potent antioxidants. In particular, green tea may lower blood pressure and thus reduce the risk of stroke and coronary heart disease. Some animal’s studies suggested that green tea might protect against the development of coronary heart disease by reducing blood glucose levels and body weight . However, all these data are based on middle-aged animals’ populations, not the elderly populations, which nutritional status tends to be more adversely influenced by age-related biological and socioeconomic factors .
In recent years, the health benefits of consuming green tea, including the prevention of cancer and cardiovascular diseases , the anti-inflammatory , antiarthritic , antibacterial , antiangiogenic , antioxidative , antiviral , neuroprotective , and cholesterol-lowering effects of green tea and isolated green tea constituents are under investigation. However, adding green tea to the diet may cause other serious health concerns.
Tea components possess antioxidant, antimutagenic, and anticarcinogenic effects and could protect humans against the risk of cancer by environmental agents . Sano et al . reported the inhibitory effects of green tea leaves against tert-butyl hydroperoxide-induced lipid peroxidation, and a similar antioxidant effect on the kidney was observed after oral administration of the major tea polyphenol EGCG. The antioxidative potency of crude catechin powder and individual catechins was tested in experiments using the active oxygen method. Crude catechins reduced the formation of peroxides far more effectively than dl-α-tocopherol . Shim et al . studied the chemopreventive effect of green tea among cigarette smokers and found that it can block the cigarette-induced increase in sister chromatid exchange frequency.
Recent data from human studies indicate that the consumption of green tea and green tea extracts may help reduce body weight, mainly body fat, by increasing postprandial thermogenesis and fat oxidation. In a randomized, double-blind, placebo-controlled, cross-over pilot study, six overweight men were given 300 mg EGCG per day for two days. Fasting and postprandial changes in energy expenditure and substrate oxidation were assessed. Resting energy expenditure did not differ significantly between EGCG and placebo treatments, although during the first postprandial monitoring phase, respiratory quotient values were significantly lower with EGCG treatment compared to the placebo. These findings suggest that EGCG alone has the potential to increase fat oxidation in men and may thereby contribute to the antiobesity effects of green tea. However, more studies with a greater sample size and a broader range of age and body mass index are needed to define the optimal dose .
In vivo studies showed that green tea catechins increase total plasma antioxidant activity . Intake of green tea extracts also increases the activity of superoxide dismutase in serum and the expression of catalase in the aorta; these enzymes are implicated in cellular protection against reactive oxygen species . This action is combined with direct action on oxygen species by a decrease in the nitric oxide plasma concentration . Malondialdehyde, a marker of oxidative stress, also decreases after green tea intake . These results suggest that catechins could have a direct or indirect effect. Since catechins can act as antioxidants in vitro , they might prevent the oxidation of other antioxidants, such as vitamin E. However, ingestion of green tea catechins does not modify the plasma status of vitamins E and C in vivo . Nevertheless, one study reported that catechins increase vitamin E concentration in low-density lipoprotein and in this way could protect low-density lipoprotein against peroxidation .
Hsu et al . demonstrated the effects of supplementation with decaffeinated green tea extract on hemodialysis-induced reactive oxygen species, atherosclerotic disease risk factors, and proinflammatory cytokines. The pharmacokinetics of one oral dose of catechins was compared between healthy subjects and hemodialysis patients. The authors compared the antioxidant effects of three different doses of oral catechins with that of oral vitamin C during a hemodialysis session. In patients, catechin supplementation reduced hemodialysis-enhanced plasma hypochlorous acid activity more effectively than did placebo or vitamin C. Between the treatments with 455 and 910 mg catechins, no significant difference was found in the reduction of plasma hypochlorous acid activity. Catechins also significantly reduced proinflammatory cytokine expression enhanced by hemodialysis.
Composition of green tea, black tea, and black tea infusion
1 NPO International Laboratory of Biochemistry, 1-166 Uchide, Nakagawa-ku, Nagoya, 454-0926, Japan
The health-promoting effects of green tea are mainly attributed to its polyphenol content , particularly flavanols and flavonols, which represent 30% of fresh leaf dry weight . Recently, many of the aforementioned beneficial effects of green tea were attributed to its most abundant catechin, -epigallocatechin-3-gallate . Green tea extracts are more stable than pure epigallocatechin gallate, one of the major constituents of green tea, because of the presence of other antioxidant constituents in the extract . In general, herbal medicines are complex mixtures of different compounds that often act in a synergistic fashion to exert their full beneficial effect . However, relatively few herbal medicines have been well characterized and their efficacy demonstrated in systematic clinical trials as compared to Western drugs. This review article highlights the recent research on the efficacy, action mechanisms, and side effects of green tea and its catechins in in vitro , in vivo , and ex vivo systems .
Although green tea has several beneficial effects on health, the effects of green tea and its constituents may be beneficial up to a certain dose yet higher doses may cause some unknown adverse effects. Moreover, the effects of green tea catechins may not be similar in all individuals. EGCG of green tea extract is cytotoxic, and higher consumption of green tea can exert acute cytotoxicity in liver cells, a major metabolic organ in the body . Another study found that higher intake of green tea might cause oxidative DNA damage of hamster pancreas and liver . Yun et al . clarified that EGCG acts as a pro-oxidant, rather than an antioxidant, in pancreatic β cells in vivo . Therefore, high intake of green tea may be detrimental for diabetic animals to control hyperglycemia. At a high dose , green tea extract induced a thyroid enlargement in normal rats . This high-level treatment modified the plasma concentrations of the thyroid hormones. However, drinking even a very high dietary amount of green tea would be unlikely to cause these adverse effects in humans.
Long-term consumption of tea catechins could be beneficial against high-fat diet-induced obesity and type II diabetes and could reduce the risk of coronary disease. Further research that conforms to international standards should be performed to monitor the pharmacological and clinical effects of green tea and to elucidate its mechanisms of action.
The antihyperglycemic effect of black tea was reported by Gomes et al . . EGCG was found to inhibit intestinal glucose uptake by the sodium-dependent glucose transporter SGLT1, indicating its increase in controlling blood sugar . Streptozotocin diabetic rats showed increased sensitivity to platelet aggregation and thrombosis, and this abnormality could be improved by dietary catechins from green tea . Alloxan produces oxygen radicals in the body, which cause pancreatic injury and are responsible for increased blood sugar.
The effects of tea on obesity and diabetes have received increasing attention. Tea catechins, especially EGCG, appear to have antiobesity and antidiabetic effects . African black tea extract has been shown to suppress the elevation of blood glucose during food intake and reduce the body weight in KK-A/TaJcl diabetic mice . Although few epidemiological and clinical studies have shown the health benefits of EGCG on obesity and diabetes, the mechanisms of its actions are emerging based on various laboratory data. These mechanisms may be related to certain pathways, such as through the modulations of energy balance, endocrine systems, food intake, lipid and carbohydrate metabolism, and redox status .
Beneficial effects of green tea A green tea articles literature reviewBeneficial effects of green tea A green tea articles literature review
In a study by Sabu et al . , administration of GTPs to normal rats increased glucose tolerance significantly at 60 minutes. GTPs were also found to reduce significantly serum glucose levels in alloxan diabetic rats at a dose of 100 mg/kg. Continued daily administration of the extract at 50 or 100 mg/kg produced 29% and 44% reduction, respectively, in the elevated serum glucose level produced by alloxan administration. Elevated hepatic and renal enzymes produced by alloxan were found to be reduced significantly by GTPs. The serum lipid peroxidation level was increased by alloxan and reduced significantly by the administration of 100 mg/kg of GTPs. Decreased liver glycogen resulting from alloxan administration showed a significant increase after GTP treatment. The GTP-treated group showed increased antioxidant potential, as seen from improvements in superoxide dismutase and glutathione levels. However, catalase, lipid peroxidation, and glutathione peroxidase levels were unchanged. These results indicate that alterations in the glucose utilizing system and oxidation status in rats that were increased by alloxan were partially reversed by the administration of GTPs .
The effectiveness of green tea in treating any type of diarrhea and typhoid has been known in Asia since ancient times . Green tea catechins have an inhibitory effect on Helicobacter pylori infection . Effects of green tea against the influenza virus, especially in its earliest stage, as well as against the Herpes simplex virus have also been demonstrated . Furthermore, Weber et al . observed that adenovirus infection is inhibited in vitro by green tea catechins.
The authors read full articles and reached consensus after discussion. Articles included in the study covered the following effects of green tea: the health benefits in humans and animals, absorption of metal ions and drug-metabolizing enzymes, antioxidation and inhibition of oxidative stress, carbohydrate metabolism and diabetes mellitus, and adverse effects. A total of 105 peer-reviewed papers in English were selected for this review.
The authors declare that they have no competing interests.
EGCG: epigallocatechin-3-gallate; GTPs: green tea polyphenols; UDP: Uridine di-phospatase; IQ: 2-amino-3-methylimidazol quinoline; MEDIS: Mediterranean Islands; SDLT: Sodium dependent glucose transporter; AMED: Allied and complementary Medicine Database.
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The review on green tea and its catechins focused on language literature in English. The literature search was conducted in the following databases: Pubmed , EMBASE , Allied and complementary Medicine Database and China Journals Full Text Database . The keywords used were selected from the following terms: green tea, catechins, anticancer, diabetes, polyphenols, in vivo studies, general pharmacology and toxicology. The health benefits and adverse effects of green tea and its catechins were reviewed.
2 Amala Cancer Research Center, Amala Nagar, Thrissur, Kerala, 680 555, India
Lambert et al . showed that intragastric administration of EGCG at a dose of 75 mg/kg resulted in a Cmax of 128 mg/l total plasma EGCG and a terminal half-life of 83 minutes. Furthermore, in humans an oral intake of EGCG at a dose of 50 mg resulted in a Cmax of 130 mg/l total plasma EGCG and a terminal half-life of 112 minutes . These results indicate that rodents must be orally administered 100- to 600-fold more EGCG to achieve similar plasma concentrations as those found in humans. Total plasma EGCG concentrations shown to be efficacious in mice and rats can be reached by an intake of low to moderate doses of EGCG in humans.
Pilipenko et al . assessed the tolerance of tableted green tea and its effect on the antioxidant status indices. Twenty-five patients with different gastrointestinal pathologies were included in the study and divided into treatment and control groups. The tolerance of tableted green tea was good in the treatment group, who showed better dynamics of quality-of-life indices, green tea articles especially in scales of body pain and social functioning. There were no significant differences in biochemical analysis between the groups, which may indicate the safety of this product. Analysis revealed that the treatment group showed a decreased level of all antioxidant status indices, as reflected in a significant decreasing of the lipid peroxidation index from 4.63 to 4.14.
Catechins also reduced plasma triglyceride levels in an oral glucose-tolerance test in normal rats . Green tea extract intake reduced these values in both Zucker rats and rats fed a sucrose-rich diet . Several human- and animal-based studies suggested that green tea and its flavonoids have antidiabetic effects . Green tea flavonoids were also shown to have insulin-like activities as well as insulin-enhancing activity .
Type II diabetes is a heterogeneous disorder that involves resistance of glucose and lipid metabolism in peripheral tissues to the biological activity of insulin and inadequate insulin secretion by pancreatic β cells . Animal models of diabetes are available: Zucker rats, which are genetically obese; injection of streptozotocin or alloxan, which destroys pancreatic β cells; and treatment with sucrose-rich diets, which induces obesity and insulin resistance.
The Mediterranean Islands epidemiological study is a cross-sectional health and nutrition survey that aims to evaluate the association between various sociodemographic, bioclinical, dietary, and other lifestyle habits and the prevalence of the common cardiovascular disease risk factors among elderly people without a history of any chronic disease and living in the Mediterranean islands. Because data relating tea consumption with clinical characteristics are lacking in elderly populations, in the context of the MEDIS study, the authors sought to evaluate whether green tea consumption is independently associated with fasting blood glucose levels and the prevalence of type II diabetes mellitus . An earlier study was aimed at providing evidence of improvement in glucose metabolism in diabetic mice and healthy humans upon green tea consumption . Green tea promoted glucose metabolism in healthy human volunteers at 1.5 g/kg as shown in oral glucose-tolerance tests. Green tea also lowered blood glucose levels in diabetic db /db mice and streptozotocin-diabetic mice two to six hours after administration at 300 mg/kg without affecting serum insulin level, whereas no effect was observed in control mice .
Under in vivo conditions, glutathione acts as an antioxidant, and its decrease was reported in a diabetes mellitus model . The increased glutathione content in the liver of the rats treated with GTPs may be one of the factors responsible for the inhibition of lipid peroxidation. Superoxide dismutase and catalase are the two major scavenging enzymes that remove the toxic free radicals in vivo . Vucic et al . reported that the activity of superoxide dismutase is low in diabetes mellitus.
SMC and PTT did the literature search and drafted the manuscript. RK and IN critically reviewed the literature and revised the manuscript. All authors read and approved the final version of the manuscript.
In humans, Hirasawa and Takada studied the antifungal activity of green tea catechins against Candida albicans and the convenience of a combined treatment with catechins and lower doses of antimycotics, which may help to avoid the side effects of antimycotics. Green tea consumption has also been associated with increased bone mineral density, and it has been identified as an independent factor protecting against the risk of hip fractures; this effect was considered independent of smoking status, hormone replacement therapy, coffee drinking, and the addition of milk to tea . Park et al . observed the positive effects of green tea extracts and GTPs on the proliferation and activity of bone cells. The proliferation of hepatic stellate cells is closely related to the progression of liver fibrosis in chronic liver diseases, and EGCG has a potential inhibitory effect on the proliferation of these cells . Green tea strengthens the immune system action because it protects it against oxidants and radicals. Recent studies suggested that GTPs might protect against Parkinson’s and Alzheimer’s diseases and other neurodegenerative diseases . Studies have demonstrated GTP neuroprotectant activity in cell cultures and animal models, such as the prevention of neurotoxin-induced cell injury . Green tea is considered to be useful for insect stings due mainly to its anti-inflammatory effects and its capacity to stop bleeding . Some studies have suggested an inverse association between green tea consumption and the risk of kidney stone formation . In an experimental cataractogenesis system, green tea acted by preserving the antioxidant defense system of the lens . Skrzydlewska et al . indicated a beneficial effect of green tea in alcohol intoxication. In addition to all of these reported properties, which have helped the recognition of green tea as functional food by some authors , green tea is also currently used in the preparation of a variety of foods, pharmaceutical preparations, dentifrices, and cosmetics .
1 NPO International Laboratory of Biochemistry, 1-166 Uchide, Nakagawa-ku, Nagoya, 454-0926, Japan
The chemical composition of green tea is complex: proteins , whose enzymes constitute an important fraction; amino acids such as theanine or 5- N- ethylglutamine, glutamic acid, tryptophan, glycine, serine, aspartic acid, tyrosine, valine, leucine, threonine, arginine, and lysine; carbohydrates such as cellulose, pectins, glucose, fructose, and sucrose; minerals and trace elements such as calcium, magnesium, chromium, manganese, iron, copper, zinc, molybdenum, selenium, sodium, phosphorus, cobalt, strontium, nickel, potassium, fluorine, and aluminum; and trace amounts of lipids , sterols , vitamins , xanthic bases , pigments , and volatile compounds . Due to the great importance of the mineral presence in tea, many studies have determined their levels in tea leaves and their infusions 1 ) . Fresh leaves contain, on average, 3-4% of alkaloids known as methylxanthines, such as caffeine, theobromine, and theophylline . In addition, there are phenolic acids such as gallic acids and characteristic amino acid such as theanine present .
Laboratory studies showed the health effects of green tea. As the human clinical evidence is still limited, future research needs to define the actual magnitude of health benefits, establishes the safe range of tea consumption associated with these benefits, and elucidates the mechanisms of action. Development of more specific and sensitive methods with more representative models along with the development of good predictive biomarkers will give a better understanding of how green tea interacts with endogenous systems and other exogenous factors. Definitive conclusions concerning the protective effect of green tea have to come from well-designed observational epidemiological studies and intervention trials. The development of biomarkers for green tea consumption, as well as molecular markers for its biological effects, will facilitate future research in this area.
1 NPO International Laboratory of Biochemistry, 1-166 Uchide, Nakagawa-ku, Nagoya, 454-0926, Japan
Green tea contains polyphenols, which include flavanols, flavandiols, flavonoids, and phenolic acids; these compounds may account for up to 30% of the dry weight. Most of the green tea polyphenols are flavonols, commonly known as catechins. Products derived from green tea are mainly extracts of green tea in liquid or powder form that vary in the proportion of polyphenols and caffeine content . The major flavonoids of green tea are various catechins, which are found in greater amounts in green tea than in black or Oolong tea . There are four kinds of catechins mainly find in green tea: epicatechin, epigallocatechin, epicatechin-3-gallate, and EGCG . The preparation methods influence the catechins both quantitatively and qualitatively; the amount of catechins also varies in the original tea leaves due to differences in variety, origin, and growing conditions . The preparation of fresh green tea cannot totally extract catechins from the leaves; therefore, the concentration found differs from the absolute values determined through the complete extraction of leaves . Moreover, catechins are relatively unstable and could be quantitatively and qualitatively modified during the time frame of an experiment . Thus, comparison of ingested doses in animal studies is not possible because the catechin quantification before administration is often not known.
A study by Waltner-Law et al . provided compelling in vitro evidence that EGCG decreases glucose production of H4IIE rat hepatoma cells. The investigators showed that EGCG mimics insulin, increases tyrosine phosphorylation of the insulin receptor and the insulin receptor substrate, and reduces gene expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase. Recently, green tea and green tea extracts were demonstrated to modify glucose metabolism beneficially in experimental models of type II diabetes mellitus . In addition, EGCG ameliorates cytokine-induced β cell damage in vitro and prevents the decrease of islet mass induced by treatment with multiple low doses of streptozotocin in vivo .
Harmful effects of tea overconsumption are due to three main factors: its caffeine content, the presence of aluminum, and the effects of tea polyphenols on iron bioavailability. Green tea should not be taken by patients suffering from heart conditions or major cardiovascular problems. Pregnant and breast-feeding women should drink no more than one or two cups per day, because caffeine can cause an increase in heart rhythm. It is also important to control the concomitant consumption of green tea and some drugs, due to caffeine’s diuretic effects . Some studies revealed the capacity of tea plants to accumulate high levels of aluminum. This aspect is important for patients with renal failure because aluminum can be accumulated by the body, resulting in neurological diseases; it is therefore necessary to control the intake of food with high amounts of this metal . Likewise, green tea catechins may have an affinity for iron, and green tea infusions can cause a significant decrease of the iron bioavailability from the diet .
The health benefits of green tea for a wide variety of ailments, including different types of cancer, heart disease, and liver disease, were reported. Many of these beneficial effects of green tea are related to its catechin, particularly -epigallocatechin-3-gallate, content. There is evidence from in vitro and animal studies on the underlying mechanisms of green tea catechins and their biological actions. There are also human studies on using green tea catechins to treat metabolic syndrome, such as obesity, type II diabetes, and cardiovascular risk factors.
* Data refer to dry weight of tea leaves.
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Tea is one of the most popular beverages consumed worldwide. Tea, from the plant Camellia sinensis , is consumed in different parts of the world as green, black, or Oolong tea. Among all of these, however, the most significant effects on human health have been observed with the consumption of green tea . The first green tea was exported from India to Japan during the 17th century. It is estimated that about 2.5 million tons of tea leaves are produced each year throughout the world, with 20% produced as green tea, which is mainly consumed in Asia, some parts of North Africa, the United States, and Europe . The association between tea consumption, especially green tea, and human health has long been appreciated . Green tea and black tea are processed differently during manufacturing. To produce green tea, freshly harvested leaves are immediately steamed to prevent fermentation, yielding a dry, stable product. This steaming process destroys the enzymes responsible for breaking down the color pigments in the leaves and allows the tea to maintain its green color during the subsequent rolling and drying processes. These processes preserve natural polyphenols with respect to the health-promoting properties. As green tea is fermented to Oolong and then to black tea, polyphenol compounds in green tea are dimerized to form a variety of theaflavins, such that these teas may have different biological activities.
Tea has been shown anticarcinogenic effects against breast cancer in experimental studies . However, epidemiologic evidence that tea protects against breast cancer has been inconsistent . A case-control study was conducted in southeastern China between 2004 and 2005 . The incidence cases were 1009 female patients aged 20-87 years with histologically confirmed breast cancer, and the 1009 age-matched controls were healthy women randomly recruited from breast disease clinics. Information on duration, frequency, quantity, preparation, and type of tea consumption as well as diet and lifestyle were collected by face-to-face interviews using a validated and reliable questionnaire. In comparison with non-tea drinkers, green tea drinkers tended to reside in urban settings, to have more education, and to consume more coffee, alcohol, soy, vegetables, and fruits. After adjusting established and potential confounding factors, green tea consumption was associated with a reduced risk of breast cancer. Similar dose-response relationships were observed for duration of drinking green tea, number of cups consumed, and new batches prepared per day.
Tea catechins can affect iron absorption, particularly in groups at risk of iron deficiency , but their effects on other ions are poorly understood. Green tea ingestion over a long period does not affect the apparent absorption of copper, whereas it decreases that of zinc and increases that of manganese . However, catechin intake does not affect the plasma concentration of these ions . Green tea catechins have the potential to affect absorption and metabolism of ions because flavonoids interact with a variety of metal ions .
Studies using animal models show that green tea catechins provide some protection against degenerative diseases . Some studies indicated that green tea has an antiproliferative activity on hepatoma cells and a hypolipidemic activity in hepatoma-treated rats, as well as the prevention of hepatoxicity and as a preventive agent against mammary cancer post-initiation . Green tea catechins could also act as antitumorigenic agents and as immune modulators in immunodysfunction caused by transplanted tumors or by carcinogen treatment . Moreover, green tea, its extract, and its isolated constituents were also found to be effective in preventing oxidative stress and neurological problems . do green tea really help lose weight

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