Researchers have identified a hormone naturally produced by the body that cut the amount of food volunteers consumed by up to 36%, a finding that could eventually lead to new types of natural weight-loss drugs.
The hormone "is what stops you from having a third helping," said Dr. Stephen Bloom of Imperial College in London, who led the study. The hormone, called PYY3-36, was shown to reduce food intake in rats over a long period, the team reports in today's issue of the journal Nature.
New ways of controlling weight gain are desperately needed. Some researchers estimate that as much as 60% of the American population is overweight, and the obesity epidemic is extending to childhood. About 13% of children and 16% of adolescents are estimated to be overweight, and the proportion is growing rapidly, fueled by fast food and lack of exercise. New studies have shown that obesity is the second leading cause of preventable deaths, after smoking.
Weight-loss drugs and programs are a $40-billion-per-year industry--and growing. There are about 15 drugs for treating obesity that are in human clinical trials or about to begin them, according to a recent study by the market research firm Marketdata Enterprises Inc. But many diet drugs produce only modest weight loss. The loss does not persist for long periods and most drugs have undesirable side effects, such as hyperactivity and extreme dry mouth.
"If we are to combat the global obesity epidemic, such breakthroughs [as this] are urgently needed," wrote Dr. Michael W. Schwartz of the University of Washington in an editorial in the same journal.
Experts agree that it will be years before a useful drug can be produced from the new finding--if one can be at all. One stumbling block, for example, is that the hormone cannot be administered orally because acids in the stomach would destroy it.
But this discovery certainly represents one of the most promising leads in recent years.
Many hormones that reduce appetite have been identified, "but this one has important features that distinguish it from the others," said Dr. David E. Cummings of the Veterans Affairs Puget Health Care System and the University of Washington.
Its effects lasted longer than those of other hormones and repeated injections produced long-lasting appetite suppression and weight loss in rats, he said.
