Can Green Tea Fight Cancer?
June 14, 2000
New York Times Syndicate
Ever since Chinese Emperor Shen Nung discovered tea in 2737 BC - or so legend has it - the leafy brew has been hailed as a small miracle of natural medicine.
``Anywhere a person cultivates tea, long life will follow,'' a Japanese monk wrote in 1211. Green tea, especially, is said to be good for the heart, to prevent cancer, improve digestion and mitigate the effects of aging.
Now, as tea is winning converts among the health conscious, scientists are using modern molecular tools to probe the reputed secrets of the ancient herb. Green tea - and black tea, but less so - contains cancer-fighting antioxidants, flavenoids and a range of other substances still unknown.
At the same time, researchers in Japan and elsewhere are comparing cancer rates among heavy tea-drinkers and those who consume little, looking for telltale patterns. These studies are small and preliminary, and have had conflicting results. One showed that both men and women who drank 10 or more cups of green tea daily developed cancer several years later than non-drinkers.
Green tea, black tea and oolong all come from the same evergreen shrub, Camellia sinensis, but they are prepared differently. Black tea is the rule in Western countries, while green tea predominates in Asia.
All this research activity and some of the findings add to the growing mystique suggesting that green tea may be a safe and relatively easy-to-take component of cancer prevention.
``There are reasons to think that green tea might protect against cancer,'' said Dr. Michael Thun, an epidemiologist with the American Cancer Society. ``And basically the findings are that there may well be an effect, but it's a long, long way from conclusive.''
That's the U.S. scientific view. In Japan, however, where many of the epidemiological studies have been done, green tea is already proclaimed a winner. ``The government says so, and there is a popular consensus,'' said Dr. Hirota Fujiki, a pioneer who has been pursuing the tea-cancer connection since the mid-1980s. Fujiki is a scientist at the Saitama Cancer Center Research Institute in Saitama.
In an interview, he described some key studies, including one in which 419 cancer patients were identified among 8,552 individuals. Over 10 years, the scientists reported, onset of the disease in those who developed cancer was 7.2 years later among women tea-drinkers and 3.0 years later among men, than among the patients who drank fewer than three cups of green tea a day. (Those with the delayed onset drank 10 or more Japanese cups - medium sized by Western standards - of tea daily.)
Fujiki also identified the active substance (or at least a crucial one