Green tea is consumed primarily in China, Japan, and a few countries in North Africa and the Middle East. In many Japanese or Chinese restaurants, one of the dessert options is green tea ice cream. In recent years green tea has become popular in Europe and North America and now green tea pills are touted for weight loss, as potent antioxidants, and for tumor prevention. What does the research say about the benefits of green tea pills? Do green tea supplements help with weight loss and are they an effective diet aid?
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Potential health benefit of green tea
Human research is still very early, but the potential health benefits ascribed to green tea include antioxidant effects, cancer chemoprevention, antiviral effects, blood thinning properties, improving cardiovascular health, slowing mental decline, enhancing weight loss, arthritis protection, and protecting the skin from the damage caused by ionizing radiation. The compound EGCG found in green tea has been shown to regulate dozens of disease-specific molecular targets. Long term human research is required before we determine the appropriate dosage and amount of green tea or green tea extract required to provide these health benefits.

Green Tea Extract, 100 mg, yielding 35 mg EGCG - Source Naturals
Green Tea Extract offers a convenient way to get the benefits of green tea in a highly concentrated green tea pill form.  This green tea extract is standardized for bioflavonoid-like antioxidants known as polyphenols, particularly (-)-Epigallocatechin Gallate (EGCG).  EGCG has been found in scientific studies to be a potent antioxidant. Green tea antioxidants are likely to become more popular with time.

Green Tea Supplement Facts
Calcium
Green Tea Extract Yielding 35 mg epigallocatechin gallate (EGCG)

Suggested Use: 1 green tea extract tablet a few times a week with breakfast or lunch. Take green tea extract pill in the morning or midday before or with a meal. Evening use may lead to mild insomnia.
Click here to buy Green Tea Extract, get a FREE Bottle of Diet Rx with green tea appetite suppressant, or to sign up to a highly respected and FREE nutrition newsletter

Subscribe to a FREE Supplement Research Update newsletter. Twice a month we email a brief abstract of several studies on various supplements and natural medicine topics - including benefit of green tea and green tea pills - and their practical interpretation by Ray Sahelian, M.D.

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More about green tea
Tea is the most widely consumed beverage aside from water. Green tea contains polyphenolic compounds, which account for 30% of the dry weight of the leaves. Most of the polyphenols are flavanols, of which (-)-epigallocatechin-3-gallate (EGCG) is the most abundant. Tea is manufactured in three basic forms:

Black Tea -- During black tea production, oxidation is promoted so that most of these substances are oxidized.
Green tea -- Green tea is prepared in such a way as to prevent the oxidation of green leaf polyphenols.
Oolong tea --  Oolong tea is a partially oxidized product. Of the approximately 3 million metric tons of dried tea manufactured, only 20% is green tea and less than 2% is oolong tea.

What's in Green Tea?
Fresh green tea leaf is unusually rich in polyphenols which may constitute up to 30% of the dry leaf weight. Polyphenols include catechins, flavanols, chlorogenic acid, epigallocatechin gallate (EGCG), and one unique to tea, theogallin. Caffeine in green tea is present at an average level of 3% along with very small amounts of methylxanthines, theobromine and theophylline. The amino acid theanine (5-N-ethylglutamine) is also unique to tea.

Green Tea and Weight Loss - Green Tea Diet - Is Green Tea a fat burner?
Human studies regarding the benefit of green tea in weight loss have not shown consistent results. In one study mentioned below, daily consumption of green tea for 12 weeks reduced body fat. Green tea could enhance metabolism. Scientists are still evaluating whether a green tea pill by itself leads to weight loss. See below for more green tea and weight loss research information. If you plan to drink green tea for weight loss, avoid drinking after mid afternoon or early evening so that your sleep is not disturbed.

Anti-obesity effects of green tea: from bedside to bench.
Mol Nutr Food Res. 2006 Feb;50(2):176-87. DSM Nutritional Products, Department of Human Nutrition and Health, Basel, Switzerland.
Green tea, green tea catechins, and epigallocatechin gallate (EGCG) have been demonstrated in cell culture and animal models of obesity to reduce adipocyte differentiation and proliferation, lipogenesis, fat mass, body weight, fat absorption, plasma levels of triglycerides, free fatty acids, cholesterol, glucose, insulin and leptin, as well as to increase beta-oxidation and thermogenesis. Adipose tissue, liver, intestine, and skeletal muscle are target organs of green tea, mediating its anti-obesity effects. Studies conducted with human subjects report reduced body weight and body fat, as well as increased fat oxidation and thermogenesis and thereby confirm findings in cell culture systems and animal models of obesity. There is still a need for well-designed and controlled clinical studies to validate the existing and encouraging human studies.

Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men.
American Journal of Clinical Nutrition, Vol. 81, No. 1, 122-129, January 2005
Catechins, the major component of green tea extract, have various physiologic effects. There are few studies, however, on the effects of catechins on body fat reduction in humans. We investigated the effect of catechins from green tea on body fat reduction and the relation between oxidized LDL and body fat variables. Design: After a 2-wk diet run-in period, healthy Japanese men were divided into 2 groups with similar BMI and waist circumference distributions. A 12-wk double-blind study was performed in which the subjects ingested 1 bottle oolong tea /d containing 690 mg catechins (green tea extract group; n = 17) or 1 bottle oolong tea /d containing 22 mg catechins (control group; n = 18). Results: Body weight, BMI, waist circumference, body fat mass, and subcutaneous fat area were significantly lower in the green tea extract group than in the control group. Conclusion: Daily consumption of green tea containing 690 mg catechins for 12 wk reduced body fat, which suggests that the ingestion of catechins from green tea might be useful in the prevention and improvement of lifestyle-related diseases, mainly obesity.

Effect of long-term oral administration of green tea extract on weight gain and glucose tolerance in Zucker diabetic (ZDF) rats.
J Herb Pharmacother. 2005;5(3):55-65. Botanical Center in Vivo Care, 700 West State St, West Lafayette, IN, 47907, USA.
There have been some claims that green tea reduces weight and lowers blood glucose in diabetes. Intraperitoneal injections of green tea catechins in diabetic rats have shown beneficial effects. To determine if oral administration of green tea would prevent development of diabetes, young Zucker diabetic rats were dosed with green tea extract containing 50-125 mg/kg of Epigallocatechin gallate (EGCG) starting at 7 weeks of age, before the appearance of excessive weight gain and glucose elevation. While there was a trend toward lower weight gain and average daily glucose, there was no statistically significant difference.

Additional Health Benefits of Green Tea
Green tea has several potential health benefits that are slowly being discovered, here are some preliminary results:
 
Anti-platelet (blood thinning) activity of green tea catechins is mediated by inhibition of cytoplasmic calcium increase.

Some green tea catechins are chondroprotective (protecting cartilage) in lab studies, and that consumption of green tea may benefit the arthritis patient by reducing inflammation and slowing cartilage breakdown. Further studies will be required to determine whether these compounds access the joint space in sufficient concentration and in a form capable of providing efficacy when ingested as tea or capsule.

Epigallocatechin-3-gallate (EGCG) has been suggested to have antiviral activity. To determine the effects of EGCG on HIV infection, peripheral blood lymphocytes infected with HIV were incubated with increasing concentrations of EGCG. EGCG strongly inhibited the replication of the HIV virus.

Green tea has preventive effects on both chronic inflammatory diseases and lifestyle-related diseases (including cardiovascular disease and cancer).

Flavanol (-)epigallocatechin-3-gallate is shown to be a potent natural inhibitor of leukocyte elastase that may be used to reduce elastase-mediated progression to emphysema and tumor invasion.

Green tea extract capsules, when given to humans, increase the production of such as glutathione S-transferase (GST) enzymes which are helpful in detoxification and cancer prevention. Dr. H.-H. Sherry Chow, of the University of Arizona, Tucson, gave volunteers four green tea extract capsules, each containing 200 mg of epigallocatechin gallate, every morning prior to eating. This provided the equivalent amount of epigallocatechin gallate obtained from drinking 8 to 16 cups of green tea daily. Those with the lowest GST levels at the start of the study and who took the green tea extracts were found to have glutathione S-transferase (GST) enzymes increased by 80 percent. Those who had good levels of glutathione S-transferase did not have much of a change in their levels. Cancer Epidemiology, Biomarkers and Prevention, August 2007.

Green Tea and Cancer:
On June 30, 2005, FDA issued a decision letter for qualified health claims for the relationship between green tea and breast cancer and for the relationship between green tea and prostate cancer. FDA wrote:

1. "Two studies do not show that drinking green tea reduces the risk of breast cancer in women, but one weaker, more limited study suggests that drinking green tea may reduce this risk. Based on these studies, FDA concludes that it is highly unlikely that green tea reduces the risk of breast cancer."

2. "One weak and limited study does not show that drinking green tea reduces the risk of prostate cancer, but another weak and limited study suggests that drinking green tea may reduce this risk. Based on these studies, FDA concludes that it is highly unlikely that green tea reduces the risk of prostate cancer."

Dr. Sahelian says: Perhaps future green tea and EGCG research will lead the FDA to make changes to their current viewpoint. There is growing evidence that drinking green tea may reduce the risk for various types of cancer. However, little is known regarding the cancer preventive benefit of green tea supplements. Even if green tea pills help reduce the incidence of cancer, we have little idea regarding the appropriate dosage.

Researchers at the University of Murcia in Spain and the John Innes Cente in Norwich, England have shown that a compound called EGCG in green tea prevents cancer cells from growing by binding to a specific enzyme. They showed for the first time that EGCG, which is present in green tea at relatively high concentrations, inhibits the enzyme dihydrofolate reductase, which is a recognized, established target for anti-cancer drugs. Green tea has about five times as much EGCG as regular tea. Green tea has been suspected to decrease rates of certain cancers but scientists were not sure what compounds were involved or how they worked. Nor had they determined how much green tea a person would have to drink to have a beneficial effect. EGCG is probably just one of a number of anti-cancer mechanisms in green tea.

Green Tea and Cancer
Green tea and its major constituent epigallocatechin gallate (EGCG) have been extensively studied as a potential treatment for a variety of diseases, including cancer. Epidemiological data have suggested that EGCG may provide protective effects against hormone related cancers, namely breast or prostate cancer. Extensive in vitro investigations using both hormone responsive and non-responsive cell lines have shown that EGCG induces apoptosis and alters the expression of cell cycle regulatory proteins that are critical for cell survival and apoptosis.
   Researchers at the University of Murcia in Spain and the John Innes Center in Norwich, England have shown that a compound called EGCG in green tea prevents cancer cells from growing by binding to a specific enzyme. They showed for the first time that EGCG, which is present in green tea at relatively high concentrations, inhibits the enzyme dihydrofolate reductase, which is a recognized, established target for anti-cancer drugs. Green tea has about five times as much EGCG as regular tea. Green tea has been suspected to decrease rates of certain cancers but scientists were not sure what compounds were involved or how they worked. Nor had they determined how much green tea a person would have to drink to have a beneficial effect. EGCG is probably just one of a number of anti-cancer mechanisms in green tea. EGCG targets multiple MMP-mediated cellular events in cancer cells and provides a new mechanism for the anticancer properties of that molecule. Understanding the basic principles by which EGCG inhibits tumour invasion and angiogenesis may lead to the development of new therapeutic strategies, in addition to supporting the role of green tea as a cancer chemopreventive agent.
     EGCG targets multiple MMP-mediated cellular events in cancer cells and provides a new mechanism for the anticancer properties of that molecule.

Green tea linked to reduced breast cancer risk
Compounds in green tea may help protect women against breast cancer. Rats who drank water containing green tea had reductions in the size and malignancy of breast tumors compared with rats that drank only water. Additionally, the tumors of tea-drinking rats developed later and were less invasive.
   While more research needs to be conducted, the findings, coupled with observations of lower rates of breast cancer in countries where green tea is consumed daily, suggest that green tea may benefit women as part of an overall healthy diet.
   According to the report in the July issue of the Journal of Cellular Biochemistry, polyphenols, compounds that are abundant in green tea, red wine and olive oil, may protect against various types of cancer. Polyphenols are potent antioxidants, compounds that help neutralize disease-causing free radicals. These cell-damaging molecules occur naturally in the body and are linked with heart disease, aging and a number of other disorders.
   Dry green tea leaves, which are about 40% polyphenols by weight, may also reduce the risk of cancer of the stomach, lung, colon, rectum, liver and pancreas, study findings have suggested.
   Breast cancer is the second-leading cause of cancer death among US women, according to the American Cancer Society.

Green Tea and Cholesterol
Consumption of green tea is associated with lower serum concentration of total cholesterol in Japanese healthy workers age 40-69 years.

A green tea extract lowers plasma cholesterol by inhibiting cholesterol synthesis and upregulating the LDL receptor in the cholesterol-fed rabbit.
Atherosclerosis. 2006 Sep 11; Wellcome Trust Centre of Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, United Kingdom; CSIRO, Health Sciences and Nutrition, Adelaide, SA 5000, Australia; University of Adelaide, SA 5000, Australia.
Green tea extracts enriched in catechins decrease plasma cholesterol in hamsters, mice and rats. The aims of this study were to determine whether a catechin-enriched extract of green tea could lower plasma cholesterol in the cholesterol-fed rabbit and to determine the mechanism of action. Conclusion: These results suggest that green tea catechins lowered plasma, liver and aortic cholesterol in the cholesterol-fed rabbit by lowering cholesterol synthesis and upregulating the hepatic LDL receptor.

Green Tea and Mental Decline
People who regularly drink green tea may have a lesser risk of mental decline as they grow older. A study of more than 1,000 Japanese adults in their 70s and beyond, found that the more green tea men and women drank, the lower their odds of having cognitive impairment. Older adults who drank two or more cups of green tea per day were about half as likely to show cognitive impairment as those who drank three cups or less each week. Men and women who averaged one cup per day fell somewhere in between.

Daily consumption of green tea catechin delays memory regression in aged mice.
Biogerontology. 2006 Sep 7; Laboratory of Bioorganic Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka , 422-8526, Japan
Because oxidative stress has been implicated in brain senescence, we investigated the effects of green tea catechin (GT-catechin), a potential antioxidant, in senescence-accelerated (SAMP10) mice. The mouse is a model of brain senescence with short life span, cerebral atrophy and cognitive dysfunction. Mice were fed water containing 0.02% GT-catechin from 1- to 15-month-old. The mean dose was about 35 mg/kg/day. We found that daily consumption of GT-catechin prevented memory regression and DNA oxidative damage in these mice. GT-catechin did not prolong the lifetime of SAMP10 mice, but it did delay brain senescence.

Green Tea and Alzheimer's
An ingredient in green tea that researchers think might fight cancer may also protect the brain from the memory-destroying Alzheimer’s disease. Scientists injected mice with an antioxidant from green tea called epigallocatechin-3-gallate (EGCG) and said it decreased production of beta-amyloid, a protein that forms the plaques that clog the brains of Alzheimer’s victims. Several months of injections reduced plaque formation by as much as 50 percent.
   Previous research had mentioned EGCG has protective effects against betaA-induced neuronal apoptosis (cell death) through scavenging reactive oxygen species, which may be beneficial for the prevention of Alzheimer's disease.
   A higher consumption of green tea is associated with a lower prevalence of cognitive impairment.

Green Tea and Leukemia
Green tea may help treat a form of adulthood leukemia. Doctors at the Mayo Clinic in Rochester, Minnesota, found that of four patients who started drinking green tea or taking green tea extracts, three showed clear improvements in their condition in the following months. The patients all had chronic lymphocytic leukemia, or CLL, a form of leukemia that usually arises during or after middle-age and typically progresses slowly. Like all types of leukemia, CLL is a cancer of the blood and bone marrow, in which abnormal white blood cells replace healthy blood cells. A study showed that one compound found in green tea, known as EGCG, was able to kill cancer cells that were taken from CLL patients and put in a test tube with the tea compound. SOURCE: Leukemia Research, online December 1, 2005.

Does Green Tea Enhance Longevity?
According to a Japanese study, those who consumed the most green tea over an 11-year period were less likely to die from cardiovascular disease or any other cause, except cancer, than were the less-frequent green tea drinkers. However, because this was an observational study, the debate on the effects of green tea on heart disease and cancer is not over. Although laboratory and animal studies have shown that the polyphenols in green tea may be protective against cardiovascular disease and cancer, it is not clear if these findings extend to humans. Dr. Kuriyama and colleagues analyzed information on 40,530 Japanese adults, 40 to 79 years old, who participated in the Ohsaki National Health Insurance Cohort Study. The subjects, who were followed from 1995 to 2005, were from a northeastern region of the country where most of the adults drink green tea three or more times per day. Adults who drank the most green tea were the least likely to die from cardiovascular disease. Men who consumed at least five cups of green tea each day were 12 percent less likely to die from any cause. Whereas, women who drank five or more cups of green tea each day were 23 percent less likely to die from any cause and 31 percent less likely to die from cardiovascular disease.
     Dr. Sahelian says: For the time being I prefer people drink a variety of herbal teas as opposed to predominantly one type of tea.

Green tea consumption and mortality due to cardiovascular disease, cancer, and all causes in Japan: the Ohsaki study.
JAMA. 2006 Sep 13;296(10):1255-65. Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
Green tea polyphenols have been extensively studied as cardiovascular disease and cancer chemopreventive agents in vitro and in animal studies. However, the effects of green tea consumption in humans remain unclear. We investigated the associations between green tea consumption and all-cause and cause-specific mortality with the Ohsaki National Health Insurance Cohort Study, a population-based, prospective cohort study initiated in 1994 among 40,530 Japanese adults aged 40 to 79 years without history of stroke, coronary heart disease, or cancer at baseline. Participants were followed up for up to 11 years (1995-2005) for all-cause mortality and for up to 7 years (1995-2001) for cause-specific mortality. Results: Over 11 years of follow-up (follow-up rate, 86%, 4209 participants died, and over 7 years of follow-up (follow-up rate, 89%), 892 participants died of cardiovascular disease and 1134 participants died of cancer. Conclusion: Green tea consumption is associated with reduced mortality due to all causes and due to cardiovascular disease but not with reduced mortality due to cancer.

Green Tea and Diabetes
Epigallocatechin gallate supplementation alleviates diabetes in rodents.
 J Nutr. 2006 Oct;136(10):2512-8. DSM Nutritional Products Ltd, Department of Human Nutrition and Health, CH-4002 Basel, Switzerland.
This study investigated the antidiabetic effects of the most abundant green tea catechin, epigallocatechin gallate (EGCG, TEAVIGO), in rodent models of type 2 diabetes mellitus and H4IIE rat hepatoma cells. We assessed glucose and insulin tolerance in db/db mice and ZDF rats after they ingested EGCG. This study shows that EGCG beneficially modifies glucose and lipid metabolism in H4IIE cells and markedly enhances glucose tolerance in diabetic rodents. Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus.

Green Tea Side effects
Green tea has caffeine and methylxanthines, so avoid drinking or taking the capsules in the evening. I have not come across any other common green tea side effects at this time except this one caution:

Caution: In rare cases extracts from green tea have been reported to adversely affect the liver. Discontinue use and consult a healthcare practitioner if you have a liver disorder or develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice. If you plan to take green tea extract for prolonged periods, take a week off each month.

Q. I have a question about the recent decision to put warning labels on supplements containing green tea extracts. it
warns of possible liver damage. Are there supplements derived from green tea extracts which will not be easily identifiable by their labels? For example if a supplement was advertised to contain "antioxidants" how would the consumer know if it contained the dangerous chemical compound in the green tea study?
   A. The study that found green tea extract polyphenols may damage liver tissue used high doses injected into small mammals. Many Japanese drink green tea several cups a day without problems. I am not concerned that taking a green tea supplement at one capsule or tablet a few times a week would cause any liver problems. As with any supplement, it is a good idea to take breaks from use. Low dosages of many supplements are often of benefit, but high dosages could be harmful.

Green Tea availability
There are countless green tea products, including tea bags, green tea capsules, tablets, powder, green tea gum, combinations of green tea with other supplements. Green tea is sold by raw material suppliers in different extracts, ranging from green tea extract 30%-95%, standardized to green tea catechins. You can also find organic green tea.

Compounds found in green tea may prevent the development of prostate cancer in men with a pre-cancerous condition called high-grade intraepithelial neoplasia (PIN). About 30,000 men die from prostate cancer in the United States every year. High-grade PIN progresses to invasive prostate cancer within a year in about 30 percent of men and no treatment is given to these men with high-grade PIN until prostate cancer is diagnosed. Green tea catechins may be one answer. A trial was performedinvolving men with high-grade PIN, who were given an inactive placebo preparation or one containing 600 milligrams of green tea catechins daily, "equivalent to 12-15 cups of green tea infusion, that is about two times the average intake in Asian countries. After a year, only 1 man among 32 in the green tea catechins group developed prostate cancer, a rate of only 3 percent. In contrast, 9 out of 30 men treated with placebo developed prostate cancer, for the expected rate of 30 percent.

Green tea extract may interfere with a process that helps early bladder cancer to spread throughout the body. The findings, say researchers, bolster ongoing studies into green tea extract as a cancer treatment -- and may give green tea drinkers more reason to savor every cup.
The investigators found that when they exposed human bladder cells to both a cancer-causing chemical and green tea extract, the extract interfered with a particular process by which early cancer cells become invasive and spread throughout body tissue. This process involves the "remodeling" of actin, a structural protein in cells that is essential for cell movement. Actin remodeling allows cancer cells to move and invade nearby healthy tissue. Based on the new findings, green tea extract may get in the way of this process by activating a protein known as Rho, which helps regulate actin's organization in cells and has been implicated in tumor development and progression.

Drinkers of green tea and oolong tea are less likely to develop hypertension than nondrinkers.

Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement1,2,3
School of Public Health, University of California, Los Angeles
American Journal of Clinical Nutrition, Vol. 80, No. 6, 1558-1564, December 2004
Black and green tea polyphenols have been extensively studied as cancer chemopreventive agents. Many in vitro experiments have supported their strong antioxidant activity. Additional in vivo studies are needed to examine the pharmacokinetic relation of absorption and antioxidant activity of tea polyphenols administered in the form of black or green tea or tea extract supplements.
The purpose of this study was to compare the pharmacokinetic disposition of black and green tea polyphenols and their effect on the antioxidant capacity in plasma 8 h after a bolus consumption of either green tea, black tea, or a green tea extract supplement. Thirty healthy subjects were randomly assigned to 3 different sequences of green tea, black tea, or a green tea extract supplement in a 3 x 3 crossover design with a 1-wk washout period in between treatments. Results: Flavanol absorption was enhanced when tea polyphenols were administered as a green tea supplement in capsule form and led to a small but significant increase in plasma antioxidant activity compared with when tea polyphenols were consumed as black tea or green tea. All 3 interventions provided similar amounts of (–)-epigallocatechin-3-gallate. Conclusions: Our observations suggest that green tea extract supplements retain the beneficial effects of green and black tea and may be used in future chemoprevention studies to provide a large dose of tea polyphenols without the side effects of caffeine associated with green and black tea beverages.

Tea beverage in chemoprevention of prostate cancer: a mini-review.
Saleem M. Nutr Cancer. 2003;47(1):13-23.
Department of Dermatology, University of Wisconsin, 1300 Medical Science Center, Madison, WI
Because prostate cancer has a long latency period and is typically diagnosed in elderly men, it represents an ideal candidate disease for chemoprevention. Therefore, even a modest delay achieved through intervention could have a significant impact on the outcome of this disease. Epidemiological and laboratory studies have provided convincing evidence that diet, genetic factors, and lifestyle are major causes of prostate cancer. Although surgery, radiotherapy, and hormone therapy are the most widely accepted curative options for a selected group of patients suffering from prostate cancer, the side effects of these treatments are many. In recent years, many dietary agents have been being described that show a wide range of chemopreventive effects in cell culture and selected animal model systems of prostate carcinogenesis. One such agent is the beverage tea, which, next to water, is the most popularly consumed beverage in the world. The epidemiological studies and recent data, amassed from various laboratories around the world, provide evidence that tea polyphenols such as epigallocatechin-3-gallate, epigallocatechin, and epicatechin-3-gallate may have the potential to lower the risk of prostate cancer in the human population. Recently, it has been shown that green tea polyphenols, when given to a transgenic mouse model that mimics progressive forms of human prostate cancer, exert remarkable preventive effects against prostate cancer development. Chemoprevention of prostate cancer by green tea polyphenols appears to occur through the modulation of various molecular targets. This article attempts to address the issue of the possible use of tea, especially green tea, for the chemoprevention of prostate cancer.

Suppression of Helicobacter pylori-induced gastritis by green tea extract in Mongolian gerbils.
Biochem Biophys Res Commun. 2003 Oct 24;310(3):715-9.
Since urease of Helicobacter pylori is essential for its colonization, we focused attention on foodstuffs which inhibit the activity of this enzyme. Among plant-derived 77 foodstuff samples tested, some tea and rosemary extracts were found to clearly inhibit H. pylori urease in vitro. In particular, green tea extract (GTE) showed the strongest inhibition of H. pylori urease, with an IC(50) value of 13 microg/ml. Active principles were identified to be catechins, the hydroxyl group of 5(')-position appearing important for urease inhibition. Furthermore, when H. pylori-inoculated Mongolian gerbils were given GTE in drinking water at the concentrations of 500, 1000, and 2000 ppm for 6 weeks, gastritis and the prevalence of H. pylori-infected animals were suppressed in a dose-dependent manner. Since the acquisition by H. pylori of resistance to antibiotics has become a serious problem, tea and tea catechins may be very safe resources to control H. pylori-associated gastroduodenal diseases.

Green tea extract and catechin ameliorate chronic fatigue-induced oxidative stress in mice.
J Med Food. 2005 Spring;8(1):47-52.
Chronic fatigue syndrome (CFS) is an illness characterized by persistent and relapsing fatigue, often accompanied by numerous symptoms involving various body systems. The etiology of CFS remains unclear, but a number of studies have shown that oxidative stress may be involved in its pathogenesis. The present study was designed to investigate the protective effect of green tea extract and catechin in the mouse model of CFS. Animals were subjected to a forced swimming test session of 6 minutes every day for 7 days; a significant increase in immobility time on successive days represented the CFS in mice. Biochemical analysis revealed that the chronic swim test significantly increased lipid peroxidation levels and decreased glutathione levels in mouse whole-brain homogenate. Treatment with green tea extract (25 or 50 mg/kg, i.p.) and catechin (50 or 100 mg/kg, i.p.) for 7 days reversed the increase in immobility time. Protection was correlated with the lowered levels of lipid peroxidation and restoration of reduced glutathione levels in the brains of fatigued mice. These findings strongly suggest the pivotal role of oxidative stress in the pathophysiology of CFS and that green tea extract and catechin could be used as potential agents in the management of CFS and warrant the inclusion of green tea extract and catechin in the treatment regimen of CFS patients.

Green tea - camellia sinensis herb -- Antiplatelet activity of green tea catechins is mediated by inhibition of cytoplasmic calcium increase. Consumption of green tea was associated with lower serum concentration of total cholesterol in Japanese healthy workers age 40-69 years; however, green tea consumption was unrelated to serum HDL-cholesterol and triglycerides.

Some green tea catechins are chondroprotective and that consumption of green tea may be prophylactic for arthritis and may benefit the arthritis patient by reducing inflammation and slowing cartilage breakdown. Further studies will be required to determine whether these compounds access the joint space in sufficient concentration and in a form capable of providing efficacy in vivo.

EGCG has protective effects against betaA-induced neuronal apoptosis through scavenging reactive oxygen species, which may be beneficial for the prevention of Alzheimer's disease.

Dietary administration of the green tea extract catechins at high doses induced goiters in rats, and this may be due to antithyroid effects of catechins.

Green tea has preventive effects on both chronic inflammatory diseases and lifestyle-related diseases (including cardiovascular disease and cancer), resulting in prolongation of life span

Flavanol (-)epigallocatechin-3-gallate is shown to be a potent natural inhibitor of leukocyte elastase that may be used to reduce elastase-mediated progression to emphysema and tumor invasion.

Raw Material Supply of Green Tea
Green tea raw material suppliers literally have dozens of forms and extracts of green tea, for example the following:
Green tea caffeine 30% to 80%
Green tea caffeine 99% Caffeine (HPLC)
Green tea catechins 20% ~ 90%;
Green tea EGCG 10% ~ 98%;
Green tea ECG, EGCg 20- 99% (HPLC)
Green tea ECG 90%, 95%;
Green tea L-theanine 20% ~ 35% ;
Green tea L-theanine 20- 50% (HPLC)
Green tea polyphenols 20% ~ 98% ;
Green tea polyphenols 20%-90% (UV-VIS)
Green tea saponins 50% ~ 70%.

Green Tea emails
Q. Will drinking a lot of green tea cause free Estrogen to go up in the body (due to the phytoestrogens)?  If so, could this potentially make someone estrogen dominant?
   A. Not likely. Phytoestrogens have both estrogen agonist and estrogen antagonist activity in different tissues. They don't work the same way as regular estrogen hormone.

Q. Recently I discovered your web page regarding health benefits of green tea. Thank you the info was very useful. If you have a moment perhaps you could clarify something for me though. A friend of mine yesterday said she read that if you drink green tea with cow's milk that it will completely destroy the antioxidant properties of green tea. Do you know if this is true?
   A. We have no indications at this time that drinking green tea with milk destroys its benefits.

Q. Is green tea okay to drink during pregnancy? Is green tea good for nausea during pregnancy.
   A. I can't foresee green tea, a cup a day, to pose any problems during pregnancy. I don't think green tea helps relieve nausea.

Q. I am trying my best to lose weight, but am unfortunately not noticing any difference. I eat healthy food and do exercise, so I am considering taking a green tea tablet to try and burn fat. I read off a bottle of green tea tablets that you should consult with your physician if you are on medications before starting the tablets. I have minor epilepsy and take three medications to keep it under control. I take Keppra, Tegretol XR and Lamictal everyday morning and night. Can I take green tea tablets as well, without any side effects from my epilepsy drugs?
   A. Green tea tablets are unlikely to cause weight loss by themselves. Anyone with a seizure disorder needs to be careful taking herbs, especially those that have a stimulating nature.

Q. Do you have a green tea recipe? What brand green tea should I use?
   A. I personally don't. But I am sure you can find a green tea recipe by doing an internet search. Various brands of green tea are available including Lipton green tea, Arizona green tea. I have recently come across some restaurants that serve green chai tea and even heard of green tea frappuccino recipe. I think alternating different green tea products is a good option.

Q. Do any doctors advocate that people take green tea supplements for their antioxidant and other benefits? If so, what's the amount of green tea they -- or that you -- advise taking daily? I find studies showing green tea benefits this or that, but I can't find anyone who actually suggests a daily amount.
   A. There is no single answer since there are many factors that are involved in green tea dosage including age, medical condition, other supplements taken, other medicines used, activity level, whether they drink coffee or tea and how much, sleep patterns, etc. Also it depends on the extract potency, the quality of the green tea, etc.

Q. If I drink a lot of green tea will it flush out the good stuff in my body and mess up my electrolytes? I was told that if I drink green tea all day or a lot of it then it isn't good for me.
   A. As a general rule, it is not a good idea to drink or eat too much of the same fluid or food. Too much green tea could cause alertness and interfere with sleep since green tea has caffeine and other methyl-xanthines such as theobromine which cause shallow sleep if ingested in the evening. It is a good idea to drink a variety of different herbal teas, not just exclusively green tea.

Q. I have bought most of your excellent soft cover booklets over the years, and always read carefully your materials when they come up in my research engine etc. I have one simple question requiring only a yes or no. And if your time permits and wish a short elaboration, that would deeply be appreciated. It deals with green tea...and I have read your web page on this. I'm a daily user of fresh juice extractor drinks plus nutraceuticals (capsule powers) I add to them, for health, fitness, metabolism controls and nootropic purposes going toward the alkaline level etc. I've read your data on green tea...and while I've begun doing it recently...my question is. Is it okay to add the contents of a quality green tea
bag to my drinks as a powder for supplementary purposes. How far removed is an extract from the green tea bag powder - As you know a really good supplemented nutritional program can be quite expensive. So if this green tea bag content has no bad side effects, I would like to continue this practice.
   A. I don't see any reason why the green tea bag contents cannot be used. Over time, use different green tea bags from different sources. The answer is yes, it is okay to use the green tea bag content in a drink.