Effects of bariatric surgery on gastrointestinal function.

Effect of Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) on gastric emptying, small intestinal transit, gut hormones, glycaemia, plasma insulin, haemodynamics, absorption, appetite, gastrointestinal (GI) symptoms, plasma lipids and body weight. Gastric emptying and small intestinal transit will be measured using scintigraphy Gut hormones, glycaemia and plasma insulin will be measured by taking blood samples Plasma lipid and glucose absorption measured using a 13C triolein breath test and 3-O-methyl-glucose (3-OMG) respectively. Appetite and gastrointestinal symptoms will be measured using questionnaires. This is a prospective longitudinal study in which all obese subjects will be studied on 4 occasions: 6-8 weeks before surgery (to avoid the pre-operative dietary restriction period), and at 1, 6 and 12 months after surgery; controls will be studied once. Each study will be 6hours in duration. A group of 20 age- and gender- matched lean volunteers will serve as the “control group”, to provide “normal data” for which the results from the patients’ will be compared. The healthy subjects will only be studied once, with similar concurrent measurements of gastric emptying, gut hormones, blood glucose, blood pressure, heart rate and gastrointestinal symptoms as the surgical subjects.