A study led by a team at the Veterans Affairs (VA) Puget Sound Health Care System and the University of Washington (UW) compared blood samples from dieters and gastric-bypass patients and found dramatic differences in the levels of "ghrelin," a hormone secreted by the stomach. The hormone was first identified by Japanese researchers in 1999, and was shown by British scientists last year to trigger appetite in humansthe first known hormone to do this.
The new findings may explain why keeping off excess weight through dieting, exercise or even medication is often a constant uphill battle, whereas obese patients who lose up to 200 pounds or more through gastric bypass surgery tend to keep off the pounds permanently. The study shows that dieting raises ghrelin, while gastric bypass surgery sharply reduces it, almost to undetectable levels. The research is the first to document the effects of low-calorie dieting versus gastric bypass surgery on ghrelin levels.
According to lead author David E. Cummings, MD, the findings not only shed light on what may be an underlying reason for the success of gastric bypass surgery, but raise the possibility of a new generation of safer, more effective weight-loss drugs.
"If the absence of ghrelin contributes to the effectiveness of gastric bypass surgery, then we may be able to achieve at least some of that weight loss by antagonizing [blocking] ghrelin medically. If this approach works, then it might be something we could use even for people who are only modestly overweight," said Cummings, an endocrinologist with VA and UW. He added that researchers have yet to devel
Contact: Jeri Rowe
VA Research Communications Service