Background There is evidence to suggest that the particulate resin colestyramine, a bile acid sequestrant formerly used as a cholesterol-lowering agent, enhances secretion of the gut hormone cholecystokinin (CCK). Established physiological actions of CCK include inhibition of gastric emptying and induction of satiation. This study evaluated the hypothesis that colestyramine, which is luminally retained, would slow gastric emptying of liquids and suppress appetite in humans.
Methods Nine healthy volunteers consumed 500 mL liquid test meals containing 4 g colestyramine, 12 g colestyramine, or control (water alone), on three occasions, in a randomized order. The effect of colestyramine on gastric emptying was determined non-invasively using the 13C-acetate breath test, and appetite and other gut-centered sensations were rated using visual analog scale questionnaires.
Key Results Colestyramine dose dependently slowed liquid gastric emptying compared with control (water) (4 g vs control, ∼20% reduction, P < 0.05; 12 g vs control, ∼35% reduction, P < 0.01). Colestyramine also significantly reduced hunger (4 g vs control, ∼20% reduction, P < 0.01), and the amount of food participants felt able to eat (12 g vs control, ∼32% reduction, P < 0.001), but increased bloating (both doses, P < 0.05), with no effect on ratings of nausea.
Conclusions & Inferences This study provides the first evidence that colestyramine significantly slows liquid gastric emptying and reduces appetite in healthy humans. Colestyramine therefore presents an attractive gut-brain signaling research tool in that it is not absorbed and thus lacks potentially confounding postabsorptive effects. Furthermore, with clear effects on gastric emptying and appetite, colestyramine now merits consideration as a trial therapeutic strategy for appetite suppression and weight loss.