Older women who regularly drink green tea may have slightly lower risks of colon, stomach and throat cancers than women who make no time for tea, a large study suggests.
Researchers found that of more than 69 000 Chinese women followed for a decade, those who drank green tea at least three times a week were 14% less likely to develop a cancer of the digestive system.
That mainly meant lower odds of colon, stomach and oesophageal cancers.
Green tea drinkers are healthier
No one can say whether green tea, itself, is the reason. Green-tea lovers are often more health-conscious in general. The study did try to account for that, said senior researcher Dr Wei Zheng of the Vanderbilt University School of Medicine in Nashville.
None of the women smoked or drank alcohol regularly. And the researchers collected information on their diets, exercise habits, weight and medical history.
Even with those things factored in, women's tea habits remained linked to their cancer risks, Dr Zheng noted.
Still, he said, this type of study cannot prove cause-and-effect.
What's more, past studies have so far come to conflicting findings on whether green-tea drinkers really do have lower cancer risks.
Safe in moderate amounts
But there is "strong evidence" from lab research - in animals and in human cells - that green tea has the potential to fight cancer, Dr Zheng's team writes in an issue of the American Journal of Clinical Nutrition.
Green tea contains certain antioxidant chemicals - particularly a compound known as EGCG - that may ward off the body-cell damage that can lead to cancer and other diseases.
Dr Zheng and his colleagues looked at data from a long-running health study of over 69 000 middle-aged and older Chinese women. More than 19 000 were considered regular green-tea drinkers, consuming it at least three times per week.
Over 11 years, 1 255 women developed a cancer of the digestive system. In general, the risks were somewhat lower when a woman drank green tea often and for a long time.
For example, women who said they'd regularly had green tea for at least 20 years were 27% less likely than non-drinkers to develop any digestive system cancer. And they were 29% less likely to develop colorectal cancer, specifically.
Women who consumed a lot of green tea in this study were also younger, ate more fruits and vegetables, exercised more and had higher-income jobs. The researchers adjusted their data for all those differences - but, they write, it's not possible to perfectly account for everything.
Green tea is safe in moderate amounts, says the National Center for Complementary and Alternative Medicine. But the tea and its extracts do contain caffeine, which some people may need to avoid. Green tea also contains small amounts of vitamin K.
(Reuters Health, October 2012)
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