The Skinny on Herbs for Weight Loss

 

While dozens of such elixirs crowd the shelves of health food stores, so far no herbal product has been proven safe and effective in controlled clinical trials. By William Collinge

Question:
Have any of those herbal weight-loss products been proven to work?

Answer:

April 3, 2000 (Mill Valley, Calif.) -- Not yet. While dozens of such elixirs crowd the shelves of health food stores, so far no herbal product has been proven safe and effective in controlled clinical trials. What's more, some of the most widely used weight-loss herbs can be downright dangerous.

For example, ephedrine, contained in ma huang extract and many other herbal diet products, is a nervous system stimulant that can cause liver and kidney damage and high blood pressure. Researchers suspect that it has also contributed to several deaths, and as a result the Food and Drug Administration (FDA) has been trying for years to regulate it. So-called "dieter's teas" often contain senna, aloe, buckthorn, and other plant-derived laxatives that have been found to cause diarrhea, vomiting, chronic constipation, and perhaps even death when consumed in excessive amounts, according to the July-August 1997 issue of the FDA Consumer. In recent years the FDA has received a number of "adverse event" reports related to these herbs, including reports of the deaths of four young women in which dieter's teas may have played a part.

Hydroxycitric acid (HA), another substance frequently found in weight-loss products, has been found to keep laboratory animals from gaining weight. But when researchers from Columbia University tested it on 135 overweight patients, they found that those who took HA lost no more weight than those who got a dummy pill. (The study was reported in the November 11, 1998 issue of the Journal of the American Medical Association.)

There is one herb that has shown promise in a small-scale test and appears quite safe: green tea extract. In a study published in the December 1999 issue of the American Journal of Clinical Nutrition, researchers studied the effects of green tea extract on energy expenditure and fat burning in 10 men who took either the extract (which contains caffeine), caffeine alone, or a placebo. The men who took the extract increased their energy expenditure and burned more fat than did those who took either the caffeine alone or the placebo. No side effects were reported.

Green tea extract is available in health food stores in capsule and tablet forms. But bear in mind that although this research is promising, we still don't know whether people who take this extract will really lose weight. Nor is it clear whether drinking regular green tea might have similar effects. For shedding pounds, the tried-and-true method of exercising more and eating less is still your best bet.

William Collinge, PhD, is the author of The Complete Guide to Alternative Medicine. He is based in Mill Valley, Calif.