Analysis of gallbladder bile in morbid obesity.

Thirty-seven per cent of our grossly obese patients selected for gastric bypass had cholesterol gallstones. To document the composition of the biliary lipids prior to weight loss, the bile taken from eleven obese patients at the time of gastric bypass was analyzed and the results compared with those in eleven nonobese patients undergoing elective surgery. There was extreme supersaturation of both gallbladder and hepatic bile in all obese patients. The gallbladder bile of all obese patients fell well outside the micellar zone whereas the bile from all but one of the controls fell within the micellar zone. These data provide biochemical support for the clinical association of obesity and cholesterol gallstone formation and are evidence against the possibility that gastric bypass is a lithogenic operation.