March 23, 2007 - Green tea is one of the most popular beverages to hit the U.S. market in the last decade. Unlike black tea or oolong, green tea is made from unfermented tea leaves. Because it is does not go through a fermentation process, research suggests that it contains the highest concentration of polyphenols, antioxidants that rid of the body of free radicals. Some preliminary research shows that green tea's polyphenols, particularly ECGC, stop the free-radical damage that may lead to cancer and heart disease.
But even though green tea gets a lot of props for its reputation as a healing brew, most of the studies on its effects have been done in the laboratory or in animals. The bulk of human studies have been population-based, those that follow large groups of people over a specified period of time. The results of those studies have been inconsistent. Because of that data, the Food and Drug Administration says there is no scientific evidence that drinking green tea reduces heart disease, and the agency rejected a petition last year that sought to allow the claim on tea labels. The FDA previously said that green tea probably does not reduce the risk of breast, prostate or any other type of cancer. "Green tea has a lot of wonderful active compounds that may play a role in fighting cancer and heart disease and even protecting the lining of the arteries," says Dave Grotto, spokesperson for the American Dietetic Association. "But there needs to be a lot more research."
Despite many claims to the contrary, it probably doesn't help with weight loss, either. Some studies suggest that green tea's polyphenols may boost metabolism and help burn fat. Unfortunately, "there's nothing magic about green tea," says Dr. Frank Greenway, head of the outpatient clinic at the Pennington Biomedical Research Center in Baton Rouge, La., who studies herbal supplements and obesity. "I'll be surprised if it is shown to have any profound effect on weight loss."
Don't throw out your green tea just because the studies have been less than impressive. "Herbs always play catch-up when it comes to research," says Greenway. "Green tea won't hurt you." And maybe it will do some good. Some studies show that some green-tea drinkers may actually get more health benefits than others. Try it freshly brewed, which provides more antioxidants than bottled green-tea drinks.
