Carob pulp preparation rich in insoluble fiber and polyphenols enhances lipid oxidation and lowers postprandial acylated ghrelin

Abstract

Ghrelin is an orexigenic hormone and may also affect substrate utilization in humans. This study investigates the effects of an insoluble dietary fiber preparation from carob pulp on postprandial ghrelin and triglyceride responses and substrate utilization. Dose-dependent effects of the consumption of a carob pulp preparation were investigated in a randomized single-blind cross-over study in 20 healthy subjects, aged 22 to 62 yr. Plasma glucose, total and acylated ghrelin, triglycerides and serum insulin and NEFA levels were repeatedly assessed before and after ingestion of an isocaloric standardized liquid meal with 0, 5, 10 or 20 g of carob pulp preparation over a 300 min period. Respiratory quotient (RQ) was determined after consumption of 0 or 20 g of carob. Carob pulp preparation intake lowered acylated plasma ghrelin, plasma triglycerides and serum NEFA compared to the control meal (P < 0.001). Plasma total ghrelin, plasma glucose and serum insulin concentrations did not change significantly after carob pulp preparation-enriched liquid meal consumption. Postprandial energy expenditure was increased by 43 % after liquid meal with carob compared to control meal (P < 0.001). Consumption of insoluble carob pulp preparation rich in insoluble dietary fiber and polyphenols decreases postprandial responses of acylated ghrelin, triglycerides and NEFA and alters RQ, suggesting a change towards increased fatty acid oxidation. These effects were independent of changes in plasma glucose and serum insulin levels.