The Tao of Tea
Tempest in a Teapot
Tea Totaling continued...
A Medline search of articles on tea and its health effects
yields scores of reports in the medical and scientific literature in the past
several years. What emerges is a significant body of literature from animal
studies showing that green tea may prevent heart disease and cancer. Other
studies have also suggested that it may help avert osteoporosis, a condition
characterized by fragile bones, and that it might have beneficial effects on
skin when applied topically.
Experts emphasize that the primary thrust of scientific
research has been on the pure tea products -- green, black, or oolong tea,
derived from a plant called Camellia sinensis. All of the many other
"herbal" or "medicinal" teas found in supermarkets and health
food stores may be tasty, and may be good, bad, or indifferent for your health
-- but they haven't been the focus of concentrated research, says John
Weisburger, PhD, of the American Health Foundation.
"That's an area where consumers have a right to be a little
frustrated," agrees Dave Ringer, PhD, scientific director for the American
Cancer Society. "While the various mixtures of herbs and teas may be
beneficial, they are not proven."
And not all the science has been favorable to tea. A report in
the March 1 edition of The New England Journal of Medicine looking at
green tea consumption in humans, found no effect on stomach cancers once
adjustments were made for other factors that could affect risk. Those other
factors included sex, age, history of stomach ulcer, use of tobacco or alcohol,
and other dietary habits.
With this flood of tea and tea-related health news, consumers
may want to know: What's real? What isn't? And what might be real, but is yet
to be proven?
"Scientists can always say something remains to be
proven," says Lenore Arab, PhD, professor of epidemiology and nutrition at
the University of North Carolina at Chapel Hill School of Public Health.
Studying the effects of tea is difficult because the pattern of
consumption varies from country to country -- and even within countries. And
understanding the long-term health effects of tea requires long-term studies,
In spite of the difficulties, there is a "large and
convincing body of evidence that tea is chemo-preventive," Arab tells
WebMD. "What has impressed me most recently is the accumulating evidence of
tea's protective role in prostate cancer."
And now Arab says she and other tea researchers are seeing a
protective effect against colon and rectal cancer among tea drinkers in
With regard to heart disease, Arab says a recent analysis
pooling the results of 12 studies looking at tea consumption in a quarter
million people, found that people who drink more green tea than others have
less incidence of heart attack. Intriguingly, that effect was greater in Europe
than in the U.S., she says.