A study led by a team at the UW and the Veterans Affairs (VA) Puget Sound Health Care System is the first to document the effects of low-calorie dieting versus gastric bypass surgery on ghrelin levels. David E. Cummings, in the Department of Medicine's Division of Metabolism Endocrinology and Nutrition, is principal author on the study published in the May 23 issue of the New England Journal of Medicine.
Ghrelin, an appetite-stimulating hormone secreted by the stomach, was first identified by Japanese researchers in 1999, and was shown by British scientists last year to trigger appetite in humans. According to the UW/VA study, dieting raises ghrelin, while gastric bypass surgery sharply reduces it, to almost undetectable levels.
In the study, the researchers analyzed blood samples from 13 obese patients before and after a six-month low-calorie, low-fat diet and from five patients who had undergone gastric-bypass surgery within the past one to three years. Ten normal-weight patients served as a control group. The dieters lost an average of 17 percent of their body weight, and their ghrelin levels rose 24 percent. The surgery group had lost an average of 36 percent of their weight, and their ghrelin levels had sunk to 77 percent below normal, and 72 percent below the dieters’ level. The very low levels of the surgery group did not show the pre-meal increases and post-meal decreases that were found in normal adults.
Other UW School of Medicine researchers participating in "Plasma Ghrelin Levels after Diet-Induced Weight Loss or Gastric Bypass Surgery" include David S. Weigle, associate professor of medicine in the Division of Metabolism Endocrinology and Nutrition, and E. Patchen Dellinger, professor of surgery.
May 31, 2002