Effects of Green Tea and Cancer | Alternative Cancer Blog

The Scoop on Green Tea


Green tea offers health benefits; that much we have known for years.  But it seems to be taking a while for the medical establishment to catch up with the natural health movement in determining just how good green tea can be.

Yes, a multitude of studies over the years have linked green tea consumption with cancer and heart disease prevention, lower cholesterol levels, increased fat burning, lower risk of developing diabetes and stroke, and deterring dementia.1  Researchers have found that the antioxidants in green tea can hinder the growth of cancer cells and even kill them off.  And yes, these lab results have been replicated in some human studies, but not enough to convince the medical world.  Their complaint?  That most of the human trials were conducted in Asian countries where not only green tea is a dietary staple, but fish and soy protein are as well.  They say those items might instead be what’s responsible for the health benefits garnered.

One of the studies that took place in Japan went over the records of close to 500 women who had been diagnosed with Stage I or Stage II breast cancer.2  The researchers discovered that an increase in the intake of green tea before and after surgery lowered the risk of cancer recurrence.  Other research, this time in China, found that a higher rate of green tea consumption was associated with a reduced risk of several cancers,3 including pancreatic, colorectal, stomach, esophageal, and prostate.  And, separately, a compilation of 22 studies were evaluated with results showing that drinking two cups of green tea daily can cut lung cancer risks by as much as 18 percent.

There is no disputing that the antioxidants present in green tea, known as catechins, are very healthy.  Catechins are slayers of free radicals, the destructive forces that over time play a part in the development of cancer and atherosclerosis, as well as altering and harming our very DNA.   These catechins are abundant in green tea more so than other types of tea such as oolong or black tea because green tea leaves are steamed instead of fermented.  Since less processing takes place, more antioxidants remain.

While drinking green tea can confer health benefits, there is now some debate as to whether or not it can cause any side effects when truly massive quantities are consumed — as in 50 cups a day. According to some studies green tea extract has been linked in rare instances to liver damage.4  But even the National Institutes of Health says that the evidence in these studies is not definitive; nevertheless, their experts recommend taking concentrated green tea extract supplements with food and only recommend them for people without liver disorders. It’s also worth noting that at standard doses, green tea is actually liver protective.5

The average cup of green tea contains 50 to 150 mg of polyphenols (powerful antioxidants) and the suggested amount to drink to reap benefits is two to three cups per day.  Most antioxidant formulas that incorporate green tea extract, such as Jon Barron’s Ultimate Antioxidant formula, contain approximately 125 mg — equivalent to a couple of cups of green tea.  In other words, you would need to be consuming multiple megadose capsules of a green tea supplement before you would have the slightest worry about turning benefit to harm.

And isn’t that true of just about everything in life?  Anything in excess is harmful.  Too much water can kill you.  Drinking too much water in extreme situations can cause your body to lose too many electrolytes, which can lead to convulsions, coma, and even death.   But that doesn’t mean you want to stop drinking water entirely. As with green tea, water toxicity is only seen in extreme situations — among marathon runners who don’t replace electrolytes for example.

The bottom line is that green tea offers tons of health benefits.  Even if every one of them hasn’t been proven conclusively in hundreds of independent studies, there is certainly enough evidence of its wide range of health benefits in both drinkable and supplemental form.  Add green tea to your daily diet but, like everything else, avoid absurdity.


1 Edgar, Julie. “Health Benefits of Green Tea.” WebMD. 29 August 2011.  WebMD. 11 October 2011. <http://www.webmd.com/food-recipes/features/health-benefits-of-green-tea>.

2 Nakachi, K.; Suemasu, K.; Suga, K.; et al. “Influence of Drinking Green Tea on Breast Cancer Malignancy Among Japanese Patients.” March 1998.  National Center for Biotechnology Information. 16 October 2011. <http://www.ncbi.nlm.nih.gov/pubmed/9600118>.

3 Ji, B.T.; Chow, W.H.; Hsing, A.W.; et al. “Green Tea Consumption and the Risk of Pancreatic and Colorectal Cancers.” 27 January 1997.  National Center for Biotechnology Information. 16 October 2011. <http://www.ncbi.nlm.nih.gov/pubmed/9033623?dopt=Abstract>.

4 Lambert, Joshua D.; Sang, Shengmin; and Yang, Chung S. “Possible Controversy over Dietary Polyphenols: Benefits vs Risks.” Chemical Research in Toxicology. 16 March 2007.  American Chemical Society. 16 October 2011. <http://pubs.acs.org/doi/full/10.1021/tx7000515>.

5 Arteel, G.E.; Uesugi, T.; Bevan, L.N.; et al. “Green Tea Extract Protects Against Early Alcohol-Induced Liver Injury in Rats.” March-April 2002.  National Center for Biotechnology Information. 16 October 2011. <http://www.ncbi.nlm.nih.gov/pubmed/12033455>.