Benefits of drinking tea still being sorted out by scientists

Michael Seidman, director of the Center for Integrative Medicine at the Henry Ford Health System in Detroit, hates the taste of green tea. But that doesn’t stop him from drinking a cup five days a week. When he’s done sipping, Seidman squeezes all the liquid out of the loose tea leaves and then — get this — eats them.

The leaves are so bitter that Seidman immediately brushes his teeth to remove the taste and to prevent the tea from permanently staining his teeth. “My wife just looks at me and rolls her eyes,” Seidman says. “But there’s no doubt in my mind that green tea has many health benefits.”

Other scientists are not so convinced. “There are hundreds, if not thousands, of papers on tea, but the results are often split,” notes tea researcher Jack F. Bukowski, a professor at Harvard Medical School.

So where one study finds that tea boosts immune function, another shows no effect. Most research has been limited to animals. Scientists have yet to examine all of the properties of green, black, oolong or white tea. They don’t know if the variety of tea — Darjeeling versus Jasmine green tea, for example — makes a difference. Or what effect there may be from drinking tea straight versus mixing it with milk, sugar or lemon.

“Tea has big possibilities,” says Bukowski, “but we have a long way to go before we can confirm the health benefits.”

None of that has stopped interest in tea from coming to a full boil. In January, Coca-Cola introduced Enviga, a green-tea beverage touted for burning calories. Last year, a Japanese company petitioned the U.S. Food and Drug Administration for permission to label green tea as having benefits against heart disease. (The agency denied the request, citing “supportive but not conclusive results.”)

The tongue-twisting extract of green tea — epigallocatechin gallate, known as EGCG — is an ingredient in a growing number of foods, beverages and dietary supplements.

Introduced about 5,000 years ago in China, tea became a common drink in the 6th-century Sui Dynasty. It reached Japan about 580 A.D. In 1662, Catherine of Braganza — the Portuguese-born wife of King Charles II — became the first tea-drinking queen of England. William Penn is credited with introducing tea to the Quaker colony that became Pennsylvania.

Tea drinking plummeted in the Colonies after the Boston Tea Party. But by the early 20th century, Americans were drinking enough tea to invent the tea bag and introduce iced tea, which in 2006 accounted for 85 percent of the 2.25 billion gallons of tea consumed in the United States, according to the Tea Association.

Black tea is preferred in Western countries over green tea. In the United States, tea drinkers are most concentrated in the Northeast and the South, where sweet tea is the rule.

Tea leaves are plucked from a warm-weather evergreen called camellia sinensis. Indigenous to China and India, it now thrives in mountainous regions worldwide. Oolong tea is exposed to the air for two to three hours after harvesting to oxidize and ferment it, while black tea is exposed for as long as four hours. (As for the wide range of herbal teas, they’re made from the roots, leaves and flowers of other plants and are not technically “tea” at all.)

Green tea and white tea are not oxidized after harvesting. Some scientists think that may give them a nutritional edge, because they may contain higher amounts of antioxidants. These substances not only protect against cancer, but appear to counteract the chronic inflammation that helps produce heart disease, arthritis and other diseases.

Studies of tea point to such potential benefits as improved mental alertness; lower blood cholesterol and triglyceride levels; reduced blood pressure; lower risk of breast, colon, lung, ovarian and prostate cancer; possible protection against type 2 diabetes; and maybe even weight loss.

Just be prepared to drink a lot of tea, because findings suggest that any benefits come from drinking five to 10 cups per day. Ounce for ounce, tea contains about half the caffeine found in coffee, but that could still be a lot of caffeine. Does decaf tea work as well? The results aren’t clear.

In any case, drink tea shortly after brewing it for the biggest punch of antioxidants and other healthful ingredients. If you should happen to eat the leaves, you might get an upset stomach, but otherwise no ill-health effects.

When it comes to choosing a beverage, “there is a reason to suggest that tea is a better choice,” Bukowski says. “But if you think that you’ll have tea and that will be the end of your (health) problems, you might be a bit overly optimistic.”

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