Green tea comes from the leaves of the tea plant (Camellia sinensis). It is rich in antioxidants. There are hundreds of published scientific articles that discuss health benefits of green tea constituents that come from experimental studies. Scientists have studied green tea effects on the cell level, in animal models and in human trials. Researchers have also collected green tea drinking information and health information from people by using surveys.

Ingredients

What have scientists learned from all this research? First of all, the active ingredients in green tea are antioxidants called polyphenols. Researchers performing a study on the chemistry of tea polyphenols found that flavonols and flavonols account for about 30% of the dry weight of fresh tea leaves.1 A sub-class of polyphenols, catechins, include epigallocatechin-gallate (EGCG). This is the most abundant catechin in green tea. Researchers reported in 2009 that a 6-8 ounce cup of green tea has about 90 mg EGCG in it.2

When it comes to caffeine, brewed black, green and white tea contain between 14 and 61 mg caffeine per 6-8ounce serving.3 In comparison, decaffeinated tea contains less than 12 mg caffeine per serving.

Antioxidant Capacity

A study comparing antioxidant ability of vitamins C and E to EGCG at the cellular level was reported in 2007.4 EGCG was found to have more effective antioxidizing power than both vitamins. However, when all 3 compounds were tested together, EGCG boosted the antioxidative level of protection of both vitamins. The scientists concluded that human trials should be conducted to see if the cell-level results can be obtained in vivo.

Another study reported in 2009 compared antioxidative power of various plant extracts, including extracts of white and green teas.5 Green tea extract (GTE) produced an 86% reduction of oxygen free radicals, as assayed with superoxide dismutase.

Dosage

For the prevention of cancer, Boehm and colleagues recommend a daily consumption of 3-5 cups of green tea per day.2 This dosage provides at least 250 mg of catechin per day. Another study led scientists to recommend drinking 10-15 ounces green tea per day to significantly increase the antioxidative power of blood plasma.3 In this study scientists measured antioxidant capacity of blood plasma at the time of drinking 5 ounces green tea and 60 and 120 minutes after drinking the tea.

To reduce the risk of heart attack researchers suggest drinking 3 cups of green tea each day to realize an 11% decrease in the risk of having a heart attack. To reduce the risk of dying following a heart attack, another study reported that drinking 4 cups of tea per day was warranted.6

When the analyses of the 15 tea drinks were completed they conducted human trials with the objective of measuring EGCG content in the blood.7 Their working hypothesis was that by adding EGCG to the processed drinks the catechin and caffeine ratios would be different and their fate in humans would vary from that observed from ingesting unaltered green tea.

Their results indicated that caffeine affects the absorption and metabolism of EGCG in the human body. When EGCG is ingested it is metabolized to glucuronide and sulfate compounds. In the presence of caffeine the metabolism of EGCG is depressed so blood levels of EGCG are elevated.

1The chemistry of tea flavonoids. Balentine, DA; Wiseman, SA and Bouwens, LC. Crit Rev Food Sci Nutr. 1997. 37 :693 –704.

2Green tea (Camellia sinensis) for the prevention of cancer. Boehm, K; Borrelli, F; Ernst, E; Habacher, G; Hung, SK; Milazzo, S and Horneber, M. Cochrane Database System Rev. 2009.

3Caffeine content of brewed teas. Chin, JM; Merves, ML; Goldberger, BA; Sampson-Cone, A and Cone EJ. J Anal Toxicol. 2008. 32(8):702-4.

4Physiological levels of tea catechins increase cellular lipid antioxidant activity of vitamin C and vitamin E in human intestinal Caco-2 cells. Janjira, I and S-M, Kuo. Chem Biol Interact. 2007. 169(2): 91–99.

5Anti-collagenase, anti-elastase and anti-oxidant activities of extracts from 21 plants.

Tamsyn, SA; Thring, PH and Declan P Naughton. BMC Complement Altern Med. 2009. 9:27.

6Heart Disease and Stroke Statistics—2009 Update. A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Lloyd-Jones D, Adams R, Carnethon M, et al. Circulation. 2009.119:e21-e181.

7Effects of co-administration of tea epigallocatechin-3-gallate (EGCG) and caffeine on absorption and metabolism of EGCG in humans. Nakagawa, K; Nakayama, K; Nakamura, M; Sookwong, P; Tsuduki, T; Niino, H; Kimura, F and Miyazawa, T. Biosci Biotechnol Biochem. 2009. 73(9):2014-7.

Green Tea and Pregnancy

Congratulations, you’re expecting! You’re following doctor’s orders to a tee; drinking lots of water, limiting how much fish and shellfish you are eating and taking your prenatal vitamins. You are well on your way to the day you will meet your healthy baby. What about tea? Is it okay to have some green tea with breakfast or a snack? Although green tea is generally regarded as safe by the US Food and Drug Administration, you might want to reevaluate drinking green tea before and during pregnancy no matter the health benefits it provides.

There is little scientific information about the effects of green tea on the baby in utero. This is why there aren’t concrete guidelines for how much caffeine is all right. Evaluate the information for yourself. You and your healthcare provider can make a more informed decision. You will feel more confident that you are providing the best possible environment for your baby to live and thrive.

Folic Acid

Getting enough folate is a simple yet very important thing you can do to help your baby. Neural tube defects cause spine, head and brain malformations and are associated with low levels of folate in the blood. The US recommended daily amount (RDA) of folate in women of childbearing age is 400 micrograms, according to the Office of Dietary Supplements at the National Institutes of Health.

Mothers-to-be, this includes you too! Researchers recommend that you begin taking 400 micrograms folic acid daily at least one month before conception to prevent neural tube disorders.

Here’s where green tea comes into the picture. Scientists have found that taking 5mg folic acid with green tea decreased the amount of folate in the blood by 39.9%.1 The tea they was made with 0.3 g green tea extract/250 ml water, which is a weak tea.

Scientists in Spain discovered that one of the polyphenols in green tea, epigallocatechin-3-gallate (EGCG), inhibits the enzyme that synthesizes DNA and RNA.2 This is significant because DNA contains our genetic information and determines which proteins are made according to the genetic code unique to each of us. EGCG also affects DNA methylation; a process that allows DNA to be used repeatedly without being altered. When methylation is changed, DNA’s tumor growth suppression ability is unavailable. The effect of EGCG on folate is so significant that it is labeled an “antifolate compound” in scientific literature.

Caffeine

What about your caffeine intake? Do you need that “get me going” cup of hot tea in the morning? Of course, green tea contains caffeine. Healthcare practitioners know that caffeine crosses through the placenta and stimulates the baby’s nervous system. They usually recommend that you limit your intake of caffeine-containing foods (chocolate?) and beverages. The amount that is okay for baby is unknown, because doctors don’t know the effects of caffeine on babies in utero or how babies metabolize it.

Chin and others showed that the amount of caffeine in brewed black, green and white tea products ranges from 14-61 mg per 6-8 oz serving.3 Decaffeinated teas contained less than 12 mg caffeine per serving. There was no trend in caffeine content by type of tea (black, green or white).

1Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Alemdaroglu, NC; Dietz, U; Wolffram, S; Spahn-Langguth, H and Langguth, P. Biopharm Drug Dispos. 2008. 29(6):335-48.

2Effects of folate cycle disruption by the green tea polyphenol epigallocatechin-3-gallate. Navarro-Perán, E; Cabezas-Herrera, J; Campo, LS and Rodríguez-López, JN. Int J Biochem Cell Biol. 2007. 39(12):2215-25. Epub 2007 Jun 26.

3Caffeine content of brewed teas. Chin, JM; Merves, ML; Goldberger, BA; Sampson-Cone, A and Cone EJ. J Anal Toxicol. 2008. 32(8):702-4.

Pregnant? Yes you can have your green tea…Just don’t drink it!

Health benefits can still be gained from green tea during pregnancy when it is used externally. If used topically, the catechins will not be present in elevated levels in the blood. Drinking green tea is not encouraged during pregnancy because of the caffeine content, ranging from 14 to 61 mg caffeine per 6-8 ounce serving.1 This is important because caffeine crosses the placenta and the effects of caffeine on unborn babies is not well know. Furthermore, there is no scientific research that showing it is safe to do so. On the contrary, two studies have shown that supplementation with green tea catechins, the main active ingredients in green tea, can cause reductions in birth weight and even cause birth defects.2,3

Healthy Mouth

Green tea constituents may be beneficial during pregnancy due to their antibacterial qualities. Rinsing with green tea for 30 seconds after eating a high-starch snack has been shown to reduce the incidence of cavities. One study reports that catechins in green tea are inhibitors of the enzyme in the mouth that turns starch into sugar.4 Scientists found a 70% reduction in the amount of starch changed to sugar in the mouth, effectively removing a food source for plaque-generating bacteria. Once the starch reaches the stomach the conversion to sugar occurs readily.

So, go ahead and rinse with green tea after your snack, you’ll still get to enjoy the taste of green tea (if you like it) and you’ll starve those cavity-causing bacteria.

Another contribution to a healthy mouth that is made by green tea is the prevention of gingivitis. Gingivitis is aggravated by bacteria classified as Prevotella spp. Gingivitis is identified by painful, swollen gums. Pregnant women are doubly affected because hormone changes that occur during gestation also contribute to swollen gums and you may not feel like brushing your teeth as often because it hurts. If neglected, Prevotella spp. can hide in air pockets below the gum line and eventually leading gums to recede, teeth to loosen and possibly fall out.

Scientists found that using green tea catechins in a solution of 1 mg catechins per milliliter of water as a mouthwash for 4 consecutive weeks inhibited growth of Prevotella spp.5 An added benefit found in the study is that Prevotella spp. is responsible for halitosis (bad breath) and using the mouth rinse freshened the breath.

Genital Warts

Another bothersome condition that can worsen during pregnancy is genital warts. For reasons yet to be discovered, they sometimes increase in size or bleed during pregnancy. Usually just keeping an eye on them is enough. If the warts get so big that they obstruct the vaginal opening or perineal area delivery and/or episiotomy may be a little more difficult.

Genital warts can be frozen with liquid nitrogen, burned with chemicals or lasers or given laser treatment. For a less expensive, less invasive and much more convenient treatment, an ointment of green tea extracts can be topically applied to the warts. A topical treatment of green tea extracts marketed as Polyphenon E (made by MediGene AG, Munich, Germany) was effective against genital warts in a study conducted in 2008 .6 In clinical trials, treatment of genital warts with 15% Polyphenon E ointment cleared up the warts in 53% of the cases, while treatment with 10% Polyphenon E ointment cleared 51% of the cases. For some reason, the effectiveness for women was 60% and for men it was 45%. When the scientists follow up with subjects, less than 7% of subjects experienced a recurrence of genital warts.

1Caffeine content of brewed teas. Chin, JM; Merves, ML; Goldberger, BA; Sampson-Cone, A and Cone, EJ. J Anal Toxicol. 2008. 32(8):702-4.

2Safety studies on epigallocatechin gallate (EGCG) preparations. Part 3: Teratogenicity and reproductive toxicity studies in rats, Isbruckera, RA; Edwards, JA; Wolzb, E; Davidovichc, A and Bauschb, J. Food and Chemical Toxicology. 2006. 44(5): 651-661.

3Green tea extract increases cyclophosphamide-induced teratogenesis by modulating the expression of cytochrome P-450 mRNA. Park D, Jeon JH, Shin S, Joo SS, Kang DH, Moon SH, Jang MJ, Cho YM, Kim JW, Ji HJ, Ahn B, Oh KW, Kim YB. Reprod Toxicol. 2009. 27(1):79-84.

4Inhibition of salivary amylase by black and green teas and their effects on the intraoral hydrolysis of starch. Zhang, J and Kashket, S. Caries Res. 1998. 3: 233-238.

5Effects of tea catechins on oral odor and dental plaque. Kaneko, K; Shimano, N; Suzuki, Y; Nakamura, M; Ikazaki, R; Ishida, N; Kanayasu, E; Kakuda, T; Takihara, T; Sakane, I; Yayabe, F and Matsui, T. Oral Ther. Pharmacol. 1993. 12: 189-197.

6Topical Polyphenon E in the treatment of external genital and perianal warts: a randomized controlled trial. Stockfleth E, Beti H, Orasan R, Grigorian F, Mescheder A, Tawfik H, Thielert C. Br J Dermatol. 2008 Jun;158(6):1329-38.

Green tea has been reported to have anti-inflammatory and anticancer properties that may be valuable as a skin treatment. The polyphenol epigallocatechin gallate (EGCG) is the predominant antioxidant in green tea. It is also the most beneficial polyphenol in green tea for cancer and anti-inflammation treatments.

Oxidation occurs when free radicals (+/– charged oxygen ions) react with molecules in our bodies and cause damage to cells. Browning fruit, rusting iron and ashes from your fireplace are all examples of oxidation. Oxidation is definitely something we want to prevent in our bodies. The paradox is that oxidation reactions that create free radicals are essential to our life. They include breathing (aerobic respiration), protein and fat metabolism and body tissue inflammatory response. Please note that free radicals are not just produced within our bodies; they are in our environment too. Pollutants, smoke, pesticides, alcohol and UV radiation in sunlight and also produce free radicals.

There really isn’t any way to avoid free radicals so we must battle them with antioxidants. Our bodies need a constant supply of antioxidants because once they pair up with free radicals they are no longer available to pair up with other free radicals. It is a permanent association and as long as we are alive we are also respiring, metabolizing and producing an endless supply of free radicals. The free radicals in our environment aren’t going anywhere either, unfortunately.

Psoriasis

Psoriasis is an autoimmune disease that is characterized by red, flaky lesions on the skin. The affected patches are made by inflammation and overproduction of skin cells. Scientists have identified a specific molecule called caspase 14 that plays an active role in determining which cells become skin cells, signaling cell death and in forming barrier cells. Psoriatic skin cells do not have caspase expression in the normal manner and skin cells increase in number exponentially which creates the characteristic lesions in Psoriasis. Hsu and colleagues have verified that human cells exhibiting signs of psoriasis do not contain caspase 14. In the same study they found that EGCG flips a “switch” that turns on caspace 14 activity so that normal skin cell growth can occur.1

The scientists set up another experiment based on the hypothesis that green tea phenols can bring about caspase14 activity. They studied molecular pathways required for EGCG-induced caspase 14 to work normally on skin cells by regulating cell differentiation and causing skin cell death. They concluded that a topical application of 0.5% green tea extracts significantly reduced the symptoms of psoriasis on the skin of mice by promoting efficient caspase 14 processing and cell number reduction in animal models. With further study and testing on human subjects, green tea extracts may prove useful to treat psoriatic skin disorders.2

Skin Aging from Sun Damage

Exposure to UV light from the sun is the cause of up to 90% of skin damage. Treatment of green tea polyphenols, most notably EGCG, to skin has been shown to regulate the biochemical pathways involved in inflammatory responses, including ultraviolet (UV) light-induced inflammatory markers of skin inflammation. The application of skin cream containing EGCG was found to prevent skin damage from sun exposure in animal models. The protective effects of green tea treatment on human skin are not well understood. Pharmaceutical and cosmetic companies touting the benefits of green tea in their skin care products are based on the results from studies on animal models, not necessarily on benefits obtained when applied to human skin.

Cosmetic Effects of Green Tea

There are many claims that green tea is the key to looking younger than you are. Many benefits that have been identified are not based on repeatable research of the anti-aging qualities of green tea because the research does not exist. Perhaps more research will be done in this area in the future, but for now research is focused on the anti-inflammatory and anticancerous benefits of green tea and the mechanisms behind them.

Of course, you can drink up to 5 cups of green tea each day and have negligible side effects, so long as you are not sensitive to caffeine or the tannins naturally occurring in tea. You can also use the skin products containing green tea or its extracts without risk of harm. Just don’t expect to take years off the age of your skin by using the skin products.

1Inhibition of autoantigen expression by (-)-epigallocatechin-3-gallate (the major constituent of green tea) in normal human cells. Hsu S, Dickinson DP, Qin H, Lapp C, Lapp D, Borke J, Walsh DS, Bollag WB, Stöppler H, Yamamoto T, Osaki T, Schuster G. J Pharmacol Exp Ther. 2005. 315(2):805-11. Epub 2005 Jul 26.

2Green tea polyphenol induces caspase 14 in epidermal keratinocytes via MAPK pathways and reduces psoriasiform lesions in the flaky skin mouse model. Hsu S, Dickinson D, Borke J, Walsh DS, Wood J, Qin H, Winger J, Pearl H, Schuster G, Bollag WB. Exp Dermatol. 2007. 16(8):678-684.

Inflammation

Research has shown that catechins have anti-inflammatory activity. Inflammation in the brain is associated with many neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. Investigators CK Glass and others concluded in the March 2010 issue of the journal Cell, “Although inducers of inflammation may be generated in a disease-specific manner, there is evidence for a remarkable convergence in the mechanisms responsible for the sensing, transduction, and amplification of inflammatory processes that result in the production of neurotoxic mediators.”1 They also questioned if inhibition of inflammation pathways will successfully reverse or slow the disease process.

Oxidative Stress

Green tea catechins deliver strong antioxidant capability to brain neurons. Oxidative stress produced by amyloid beta peptides (Abeta), long chains of amino acids, is involved in the development of Alzheimer’s disease.

Scientists from the University of California studied whether green tea catechins would prevent cognitive impairment in an animal model of rats afflicted with Alzheimer’s.2 The green tea catechin formulation consisted of 63% epigallocatechin-3-gallate, 11% epicatechin, 6% (-)-epigallocatechin and 6% (-)-epicatechin-gallate. The treatments, randomly assigned, were either 0.0% of the catechin formulation or 0.5% of it.

Following 20 weeks of treatment the rats receiving 0.0% catechin formulation were divided into 2 groups. One group was given a solvent that dissolves Abeta and the other group was infused with Abeta. The 0.5% catechin formulation group was split in half randomly and given the same 2 treatments, one group with the Abeta solvent and one with extra Abeta infused in them.

After 26 weeks of being given the catechin formulation the rats were put in an 8-armed radial maze to assess behavioral changes. The results they obtained suggest that long-term administration of green tea catechins provides significant protective benefits against Abeta-induced cognitive impairment by increasing antioxidative defenses.

Learning and Memory Loss

Research has documented that flavonoid-rich foods are effective at reversing age-related deficits in learning and memory in animals and humans. A study from Peking University in China tested whether flavonoids could also deliver preventative effects on aged animals.3

Mice that were 14-months old (that’s old in a mouse’s lifespan) were given either 0.025%, 0.05% or 0.1% green tea catechins in their drinking water for six months, until the mice were 20 months old. The two higher doses of catechins prevented age-related spatial learning and memory decline as evaluated by running through a water maze. Brain chemistry was evaluated after the experiment was finished and the 0.5% and .01% catechin treatments resulted in the prevention of reductions of two proteins which suggested that catechins may influence synaptic structural changes related to the hippocampus.

The most current information about the effects of flavonoid-rich foods and beverages on a variety of neurological disorders comes from JP Spencer.4 The review has been approved for publication but is not yet in print. Flavonoids limit neurological degeneration in many disorders and they also prevent or even reverse deteriorations in cognitive performance. This is carried out by flavonoids through several mechanisms. These include the potential to protect neurons from injury by neurotoxins, an ability to minimize neuroinflammation and the potential to improve memory, learning and cognitive function.

Historically the antioxidant ability of flavonoids was thought to be the sole cause of their positive activities on the brain. More recently the benefits appear to be caused by 3 separate processes. One is the enzyme-activated pathways that regulate survival factors and gene expression, second in the ability to improve blood circulation in the hippocampus and the third is their ability to destroy neurotoxic species and pro-inflammatory agents. Spencer concluded by describing how the 3 processes likely are responsible for the observed neurological effects.

1Mechanisms Underlying Inflammation in Neurodegeneration. Glass CK, Saijo K, Winner B, Marchetto MC, Gage FH. Cell. 2010. 140(6):918-934.

2Green tea catechins prevent cognitive deficits caused by Abeta1-40 in rats. Haque AM, Hashimoto M, Katakura M, Hara Y, Shido O. J Nutr Biochem. 2008.19(9):619-26. Epub 2008 Feb 15.

3Long-term administration of green tea catechins prevents age-related spatial learning and memory decline in C57BL/6 J mice by regulating hippocampal cyclic amp-response element binding protein signaling cascade. Li Q, Zhao HF, Zhang ZF, Liu ZG, Pei XR, Wang JB, Cai MY, Li Y. Neuroscience. 2009. 159(4):1208-15. Epub 2009 Feb 11.

4Nutrition Society Silver Medal Lecture Beyond antioxidants: the cellular and molecular interactions of flavonoids and how these underpin their actions on the brain. Spencer JP. Proc Nutr Soc. 2010. 17:1-17. [Epub ahead of print].

Catechins are polyphenolic compounds derived from green tea plant leaves (Camellia sinensis). They have been reported to have a wide range of biological activities including prevention of tooth decay, oral cancer and other diseases.

Halitosis

Bad breath. Green tea can wipe out the cause and symptoms. Bacteria in the mouth are responsible for the foul smell of halitosis. Polyphenols in the catechin class contained in green tea have anti-bacterial qualities and halt the biological reactions that make the smelly sulfur compounds. Green tea can both inhibit bacterial growth and alter the enzyme required to drive the production of hydrogen sulfide during protein digestion. The simple treatment for bad breath is to gargle with green tea.

Catechin Delivery to the Mouth

A study from 2004 tested the usefulness of green tea leaves to deliver catechins to the mouth.1

Subjects held 2 grams of green tea leaves in their mouths for 2-5 minutes and thoroughly rinsed their mouths. High concentrations of catechins were detected in saliva within the first hour of rinsing the mouth. The peak concentrations of catechins occurred between 25 and 44 minutes after rinsing. Researchers concluded that green tea leaves have potential for use in the prevention of oral cancer and dental caries by offering a convenient, slow-release source of catechins.

During a subsequent study on holding or chewing green tea leaves in the mouth the same scientists reported that catechin oxidation results in hydrogen peroxide as a by-product of the reaction.2 Human volunteers held green tea solution at a strength ranging from 0.1% to 0.6%. On another day the volunteers chewed 2 grams of green tea leaves. The hydrogen peroxide produced when leaves were chewed was more than when green tea solution was held in the mouth. The scientists concluded that catechin-generated hydrogen peroxide may have a significant role in disease prevention by green tea.

Green Tea and Oral Cancer Prevention

A short-term study was conducted on patients with oral premalignant lesions.3 Treatments of green tea extract was randomly assigned at doses of 500, 750 or 1000 mg/m2 or placebo three times a day for 12 weeks. The response rate to green tea extract was higher than to the placebo at all dosage rates but none of the responses were statistically significant. Even so, the two highest dosage treatments had higher responses which could be there was a dose-response effect.

The researchers concluded that the green tea extract was well tolerated at low treatment rates but at higher rates reports of insomnia and/or nervousness were made. No toxicity effect was realized. As for treatment efficacy, researchers suggested that higher doses of green tea extract in 12-week trials may improve response rates. However, the results support longer-term clinical testing of green tea extract for oral cancer prevention.

The results of this study are significant, according to Dong M. Shin at Emory University in Georgia.4 “Green tea extract was shown for the first time to have dose-dependent effects in a clinical chemopreventive setting (oral premalignant lesions). This translational trial provides important data on angiogenesis and other biomarkers on which to base future clinical research, which should include trials of green tea extract or polyphenols combined with other natural or synthetic compounds to enhance chemopreventive effects.” The study and comment were published in November of 2009, so there should be further resarch being conducted that will be reported on in the future.

1Delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract. Lee,-M-J; Lambert,-J-D; Prabhu,-S; Meng,-X; Lu,-H; Maliakal,-P; Ho,-C-T; Yang,-C-S. Cancer-Epidemiol-Biomarkers-Prev. 2004.13(1): 132-7.

2Salivary hydrogen peroxide produced by holding or chewing green tea in the oral cavity.

Lambert JD, Kwon SJ, Hong J, Yang CS. Free Radic Res. 2007. 41(7):850-3.

3Phase II Randomized, Placebo-Controlled Trial of Green Tea Extract in Patients with High-Risk Oral Premalignant Lesions. Anne S. Tsao, Diane Liu, Jack Martin, Xi-ming Tang J. Jack Lee, Adel K. El-Naggar, Ignacio Wistuba, Kirk S. Culotta, Li Mao, Ann Gillenwater, Yuko M. Sagesaka, Waun K. Hong1 and Vassiliki Papadimitrakopoulou. Cancer Prevention Research. 2009. 2:931-.

4Oral Cancer Prevention Advances with a Translational Trial of Green Tea. Dong M. Shin. Cancer Prevention Research. 2009. 2: 919.

Green tea made from tea plant leaves (Camellia sinensis) has been found to contain flavonoids, which are antioxidants in the polyphenol group. It is an abundant source of catechins. The most effective flavonoid in cancer prevention is thought to be the catechin epigallocatechin-gallate (EGCG). It is the most abundant catechin in green tea as well, making up 50-80% of the total catechins in green tea.

The CDC reported that in the US in 2006 there were 203,415 men who developed prostate cancer and 28,372 men who died from prostate cancer. It is the most common cancer among men of all races and Hispanic origin populations. It is also among the top causes of cancer death among men of all races and Hispanic origin populations.

Worldwide, prostate cancer is the second most common cancer incidence among men. Its incidence and mortality is more common in wealthy, highly developed countries. Risk and progression of prostate cancer is tied to genetic and environmental factors, especially dietary factors.

Green Tea has been used medicinally for centuries in the Far-East. Populations in countries where green tea consumption is high and tea is drunk on a daily basis have the lowest incidence of prostate cancer worldwide. There is little science-based dietary advice for the consumption of green tea to prevent prostate and other cancers.

The Research

Studies have shown that 30% of men with a certain condition known as HG-PIN would develop prostate cancer within a year of having a repeated biopsy. These results led other scientists to test the effectiveness and safety of green tea catechin as a chemopreventative drug against prostate cancer in volunteers with the HG-PIN condition.

A total of 60 volunteer subjects participated in a double-blind placebo-controlled study.1 There were 30 men in each group. The men received either a total of 600mg/day of capsules containing a total of 75.7% catechins or a placebo for one year. At the end of the year of treatment 1 tumor was found among those receiving the catechin capsule and 9 tumors were found among the placebo-treated men. No significant side effects or adverse effects were documented. The scientists concluded catechins are safe and effective for preventing pre-malignant lesions from developing into prostate cancer. A secondary observation was that the catechin capsule reduced lower urinary tract symptoms. The treatment may also be used to treat benign prostate hyperplasia symptoms.

Another investigation, a case-control study, was conducted in Hangzhou, southeast China during 2001-2002.2 There were 130 patients with confirmed prostate cancer and 274 control subjects who had no malignant diseases, including prostate cancer and whose ages matched those with prostate cancer. Tea consumption habit data was collected, including how long they have been drinking tea, quantity and frequency of tea consumption. The number of new batches of green tea brewed per day was also collected.

Among the confirmed prostate cancer cases 55% were green tea drinkers compared to nearly 80% of the control subjects. A dose response was also significant, with higher tea consumption correlating with decreasing prostate cancer incidence.

1Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Bettuzzi S, Brausi M, Rizzi F, Castagnetti G, Peracchia G, Corti A. Cancer Res. 2006. 66(2):1234-40.

2 Protective effect of green tea against prostate cancer: a case-control study in southeast China. Jian L, Xie LP, Lee AH, Binns CW. Int J Cancer. 2004. 108(1):130-5.