Green tea power - green tea, an aid in weight loss - Brief Article

Vegetarian Times, August, 2000

Green tea has been said to stave off everything from heart disease to tooth decay. Now a study published in the American Journal of Clinical Nutrition (Nov. 1999) says green tea supplements might also be a safe and effective weight-loss aid.

For the study, researchers from the University of Switzerland in Geneva recruited 10 healthy young men and had them eat their normal diets. On three occasions, the researchers measured the participants' resting energy expenditure after giving them either a concentrated green tea extract (roughly equal to four gallons of brewed tea), 50 milligrams of caffeine or a placebo three times per day. While neither the caffeine nor the placebo affected metabolism, the green tea increased energy expenditure by 4 percent--equivalent to burning 80 extra calories. What's more, unlike caffeine, the green tea didn't increase the participants' heart rates.

Previous studies have shown that caffeine boosts metabolism but only in high doses and not without an accompanying jump in heart rate. Green tea extract, on the other hand, contains very little caffeine--only one cup of coffee's worth in three pills. But that amount, researchers theorize, works synergistically with another substance contained in tea called catechins, the compounds believed responsible for green tea's health-promoting effects. This combination of catechins and caffeine seems to be the key to boosting metabolism and aiding weight loss.

Of course, popping green tea pills isn't the answer. "You can't just take this and then sit around and eat Cheetos," says Nancy Loft, D.C., an acupuncturist, dietician and director of a holistic health care center in Boca Raton, Fla. "You have to exercise to lose weight." And although Loft recommends the supplement to her patients, she agrees that further studies that include female participants need to be conducted.

Other experts give the supplements a qualified endorsement. James Duke, Ph.D., an herbalist and the author of The Green Pharmacy (Rodale Press, 1997), agrees that green tea supplements are safer than the herb ma huang, which contains the controversial stimulant ephedra. And even though the Swiss researchers didn't note any negative side effects, Duke warns that "when you concentrate any herb, you get something closer to a drug and are more likely to see side effects."

Editor's note: Though researchers used a brand of green tea extract called Exolise AR25, other brands are available. Consult a dietician for dosages.