Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, August 17, 1995 TAG: 9508170035
SECTION: NATIONAL/INTERNATIONAL PAGE: A10 EDITION: NEW RIVER VALLEY
SOURCE: ASSOCIATED PRESS|
DATELINE: NEW YORK LENGTH: Medium
Serotonin is made in the brain with a building block called tryptophan, which the brain gets from the bloodstream.
The new study suggests dieting shortchanges the brain on tryptophan delivery, reducing the production of serotonin.
The shortfall in serotonin could give dieters the urge to overeat, said researchers at Littlemore Hospital in Oxford, England. The researchers describe their study in Thursday's issue of the journal Nature.
Twelve healthy women were tested before and three weeks after starting a 1,000-calorie-a-day diet.
The women had lower levels of tryptophan when dieting. In addition, structures in the brain that respond to serotonin were more sensitive, suggesting there was less serotonin available.
In a dieter, the brain senses that those structures, called receptors, aren't getting enough serotonin and tries to fix the problem by creating urges to eat, said study co-author Dr. Elizabeth Clifford.
Drugs that suppress appetite by acting on the receptors already are in use, but scientists may be able to find better ones, she said.
Sarah Leibowitz, a neurobiologist at The Rockefeller University in New York, studies how the brain controls appetite and said there may be more to why dieters feel an urge to overeat.
Animal studies show that restricting food also alters many other brain systems, Leibowitz said, and more research is needed to find out how important each system is in producing eating urges.
Clifford agreed, ``We're just at the beginning of understanding about the control of appetite, and it's probably a lot more complicated than we realize.''
by CNB