Drinking green tea has been linked to everything from weight loss, to improving cognitive function, to lowering cholesterol. Now, two new studies suggest that this increasingly popular beverage also may help fight cancer.
"Green tea is loaded with nutrients called phenols, polyphenols, and catechins," says Mitchell L. Gaynor, MD, founder and president of Gaynor Integrative Oncology and an assistant clinical professor at Weill Cornell Medical College. "The most studied of these is a compound called Epigallocatechin gallate (EGCG). EGCG has antioxidant potential 200 times stronger than vitamin C and 20 times stronger than vitamin E."
A study published in the December issue of Cancer Biology & Therapy revealed that, in a preliminary study, EGCG from green tea appeared to significantly decrease the invasion of breast cancer cells.
Another study of almost 50,000 Japanese men, ages 40 to 69, showed that those who drank five or more cups of green tea per day were half as likely to develop progressive prostate cancer. Researchers theorize that catechin in green tea may inhibit cancer cell growth or reduce testosterone levels, thereby reducing the risk of progressive prostate cancer.
"Catechin inhibits the formation of new blood vessels that cancer cells need to grow. It also helps cancer cells regain the ability to die normally, called apoptosis," says Dr. Gaynor.
According to Dr. Gaynor, "All green teas are good, but organic is the best." He notes that white teas come from the younger tea plant and have a bit higher antioxidant activity. Black tea is fermented and has a bit less antioxidant activity, "but it is still good to drink," says Dr. Gaynor.
"Epidemiologic studies suggest lower rates of some cancers in tea drinkers, but although the studies are conflicting, it appears adding milk may negate some of the beneficial effects of tea by precipitating out the phenols," says Dr. Gaynor. In addition, recent reports suggest that low-fat and non-fat milk may actually increase the risk of prostate cancer, so it's probably best to drink your tea straight if you want to fully reap its benefits.
WHAT YOU SHOULD KNOW
* Green tea undergoes minimal oxidation during processing and is made solely with the leaves of the tea plant.
* Between one and two teaspoons of green tea should be used per cup of hot water. Steeping time can range from three to 15 minutes.
* A cup of green tea contains about 25 percent less caffeine than a cup of coffee.
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