Obese people who undergo Roux-en-Y gastric bypass surgery appear to show significant early declines in levels of ghrelin hormone that stimulates the appetite. This finding possibly explains, the loss of hunger sensation and rapid weight loss observed following gastric bypass. The study has been published in the July issue of The Archives of Surgery.
According to information in the article, the hormone ghrelin is a circulating appetite stimulant produced primarily in the stomach. It plays a presumed role in regulating body weight. Circulating ghrelin levels significantly increase before a meal and rapidly decline after eating, implicating this hormone as a principal signal of hunger and meal initiation.
Edward Lin, D.O., and colleagues at Emory University, Atlanta, conducted a study to determine if early alternations in ghrelin levels in severely obese patients undergoing weight reduction surgery may be attributed to gastric partitioning. The study included 42 patients who were morbidly obese, with a body mass index (BMI) of 40 or higher, and six lean control patients. (BMI is calculated as weight in kilograms divided by the square of height in meters.)
Thirty-four patients underwent Roux-en-Y gastric bypass (RYGB), a procedure in which the stomach is divided to create a pouch out of the smaller proximal (near) portion of the stomach, and then attached to the small intestine, bypassing a large part of the stomach and all of the duodenum. Eight patients underwent other gastric procedures that did not involve complete division of the stomach. Six non-obese patients undergoing anti-reflux surgery served as lean controls. The researchers measured ghrelin levels in blood plasma samples at different stages of surgical intervention.
"A divided gastroplasty creating a small proximal gastric pouch results in significant early declines in circulating ghrelin levels that are not observed with other gastric procedures," they report.