Carbohydrate and fat digestion is necessary for maximal suppression of total plasma ghrelin in healthy adults

It is uncertain whether the postprandial suppression of ghrelin is dependent on digestion and absorption of nutrients or whether the presence of nutrients in the small intestine is sufficient. Twenty-four healthy young adults with a mean age of 23 ± 0.6 years were examined on 3 separate days after an overnight fast. Twelve subjects participated in Part A, and the other 12 subjects in Part B. In Part A, subjects consumed, in random order, one of three study drinks: 300 mL water; 300 mL high-fat drink, with and without, 120 mg orlistat. In Part B, subjects received, in random order, one of three drinks: 300 mL water; 300 mL sucrose, with and without, 100 mg acarbose. In both parts gastric emptying as measured by 2-D ultrasound. In Part A, plasma ghrelin concentrations decreased following ingestion of the high-fat drink, but did not change with the high-fat–orlistat drink or water. In Part B, the suppression of plasma ghrelin following the sucrose drink, was attenuated by acarbose. Orlistat accelerated gastric emptying of the high-fat drink, while acarbose delayed gastric emptying of the sucrose drink. In conclusion, fat and carbohydrate digestion is required for maximal suppression of ghrelin secretion.