Tempest in a Teapot
By Mark Moran
June 4, 2001 -- Green tea, red tea, black tea -- by this time you may be swimming in tea and news about its purported ability to prevent cancer and heart disease. Now, American tea drinkers browsing the shelves of health food stores are liable to come upon a new one -- Rooibos tea, from South Africa.
"I drink it all day," says Jerry Hemelka, of San Pedro, Calif., who operates a trading company that imports Rooibos around the world. "It's excellent stuff, very mild with an aromatic taste."
Rooibos (pronounced ROY-boss) appears to be matching -- and possibly besting -- the health benefits claimed for other more established teas. A favorite among South Africans for years, the beverage is said by some to have 50% more antioxidants than are found in green tea. Antioxidants are the organic substances believed to scavenge "free radicals," the toxic by-product of natural biological processes that can damage cells and lead to cancer.
According to Hemelka, a long-time resident of South Africa, the tea is made from Aspalathus Linearis, an indigenous shrub that grows only in the mountainous region close to the Cape of Good Hope. Rooibos was discovered by the local inhabitants a long time ago, but commercially traded only since 1904, he tells WebMD.
Already commonplace in Japan, Germany, the Czech Republic, Holland, and England, Rooibos will soon sweep America, he predicts.
"It's totally unique and unknown in the United States," Hemelka says. "The United States could become the biggest market for Rooibos. If it takes off, we won't be able to supply enough to meet the demand."
Hemelka says there may be as many as 20 suppliers of Rooibos to the U.S. and more on the way. "A lot of people want to get on the bandwagon," he says.
Rooibos is sometimes used as substitute for milk with colicky babies, says Alvaro Viljoen, PhD, of the department of pharmacy at the University of the Witwatersrand. And the health benefits of Rooibos are bound to make it a favorite, he says: rich in antioxidants, rich in vitamin C, caffeine-free, and low in tannins, the residue in teas that can sometimes cause digestive problems.
"Rooibos has got all four of the buzzwords," Viljoen tells WebMD. "If you don't capture a market with those attractions, I don't think much else will sell it."
Experts agree that even without the advent of Rooibos, tea has become a veritable health phenomenon, as reports of its beneficial effects have spread in the media.
Nearly three million tons of tea are produced worldwide, according to the U.K.-based Tea Institute. Tea drinkers consumed nearly three cups a day in 1999, or a million more cups than the year before, according to the Institute.
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, she says.
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 Russia.
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.
Tea advocates say most of the health effects derive from "polyphenols," which are the antioxidants in tea. Weisburger explains that it is the oxidized form of cholesterol, for instance, that damages the surfaces of veins and arteries, leading to heart disease. "It turns out that polyphenols in tea prevent oxidation," Weisburger tells WebMD.
Weisburger was keynote speaker at this year's International Scientific Symposium on Tea and Human Health, sponsored by the U.S. Tea Council in Washington. A similar symposium will be held again next year, he tells WebMD.
The American Cancer Society has weighed in with a cautious statement on tea as a cancer preventive. Some animal studies have been shown to reduce risk, "but beneficial effects in people are not proven," according to a 1996 ACS statement on the subject.
"It's only in the last 10 year that Western science has tried to look at antioxidant activities of tea," says Dave Ringer, PhD, scientific program director at the ACS. "It's a young science. Generally, it is felt that tea can inhibit the initiation of cancer and delay its progression in animal studies. But we don't really have large well-controlled epidemiological studies to look at this yet [in humans], because you need to correct for the effects of other dietary components."
Dean Ornish, MD, says he believes some prominent medical journals, like The New England Journal of Medicine, have a bias against studies showing positive benefits of alternative treatments. Meanwhile, the "performance bar" for studies showing the positive effects of a pill or biomedical procedure is liable to be much lower, Ornish suggests.
Between a drug -- whose side effects may be known or unknown -- and a cup of tea, which is the more radical intervention, asks Ornish, director of the nonprofit Preventive Medicine Research Institute, in Sausalito, Calif., and clinical professor of medicine at the University of California School of Medicine.
Ultimately, the best reason to drink tea -- whatever its real benefits -- may be that it tastes good and there's virtually nothing wrong with it, he says.
"My attitude is if there is a potential benefit, even if not yet fully proven, and the downside is minimal if at all, why not do it?" says Ornish.
So drink up, by all means. Alvaro Viljoen, of South Africa, downs six to seven cups of Rooibos a day.
"It's nice to have before you go to bed, as well," he says. "It's very relaxing, with a bit of lemon."
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