How would you like your antioxidants? Peeled, sliced, shredded-or brewed? A current magazine ad from Lipton depicts tea on a par with fruits and vegetables. Could tea possibly be that good for you? Research suggests the answer may be yes, even though as the ad points out, tea is no substitute for fruits and vegetables.
Despite providing few nutrients, a cup of tea boasts three to five times the antioxidant power of a typical serving of fruits or vegetables-at least in the laboratory. If it proves as potent in the human body, it bodes well for the brew’s ability to promote overall health and prevent chronic diseases.
The Roots of Prevention. Tea-green, black or oolong (see sidebar “From Botanical to Brew” on page 4)-contains powerful antioxidants called polyphenols, which many researchers are convinced protect against cancer, heart disease and stroke.
Laboratory research has confirmed the cancer-fighting capabilities of several polyphenols, including catechins in green and black tea, as well as theaflavins and thearubigins in black tea. Dozens of animal studies indicate polyphenols may help protect against cancers of the breast, lung, mouth and pancreas. Research in people suggests tea may delay cancer by preventing DNA damage. Currently under study is whether tea also may slow the growth of existing tumors.
The weak link is that population studies expected to confirm that tea protects against cancer have so far been inconsistent. The widely varying results may be a consequence of studying people who don’t drink enough tea to make a measurable difference in their health. Some observers suggest that tea may protect against cancer, but only in people at high risk of disease who drink a lot of tea-as much as eight to 10 cups a day.
Other health benefits, however, have been linked to as little as one cup of tea a day. A recent Harvard study found that people who drank at least one cup of black tea a day had half the risk of heart attack-no matter what their cardiac risk factors-than tea teetotalers.
According to lead researcher Howard Sesso, D.Sc., the results also suggest that black tea inhibits oxidation of low-density lipoproteins, the process that leads to plaque buildup in arteries, giving LDL’s their “bad” cholesterol reputation. Research has also shown a lower risk of stroke for tea drinkers. But, again, population studies have failed to consistently confirm these findings.
Black and Green: Same Plant, Same Benefits? The tea question on most minds these days is whether the potential health benefits of black tea are as great as those of green tea, the one heralded in most studies up to now because that was all that was studied. For Americans, this is an important distinction, since 94% of the tea consumed in the U.S. is black tea, whether it’s your basic Lipton, Red Rose or Tetley or fancier blends like English Breakfast, Earl Grey or Darjeeling. Despite the public’s perception that green tea is superior to black, John Weisburger, Ph.D., M.D., of the American Health Foundation, doesn’t believe there’s a meaningful difference between the two.
“Both contain polyphenols,” he argues, “but with different chemical structures.” Weisburger explains that the polyphenols in both teas have been shown to fight cancer in three ways: 1) by boosting the ability of enzymes to fend off cancer, 2) by increasing the body’s ability to detoxify cancer-causing substances, and 3) by slowing the reproduction of cancer cells.
“The total polyphenol content in green and black tea is the same,” agrees Gary Beecher, Ph.D., a research chemist at the U.S. Department of Agriculture’s Food Composition Lab. Although black tea processing causes a shift in the type of polyphenols, it doesn’t change the total amount or their effectiveness as antioxidants. The only difference, he explains, is that green tea is dominated by catechins, including one called EGCG that’s been singled out for its anticancer effects in the laboratory. In processing black tea, much of the EGCG and other catechins are oxidized to theaflavins and thearubigins.
Green tea may be the sentimental favorite because it had a headstart on research, but Weisburger says, “both teas are now being researched and the results tell us both teas have the same benefits.”
Bottom Line. So, should you make time for tea? The evidence is mounting that tea-green or black-may be a healthful addition to your diet, though clearly not on the same level as fruits and vegetables. Tea doesn’t have the large amounts of nutrients-vitamins A and C, folate, calcium and fiber-found in produce. But it might not be a bad idea to ditch your morning java and take on tea instead.
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