Decreased insulin secretion and incretin concentrations and increased glucagon concentrations after a high-fat meal when compared with a high-fruit and -fiber meal.

This study was conducted to investigate whether a high-fat/high-carbohydrate (HFHC) meal induces an increase in plasma concentrations of glucagon, dipeptidyl peptidase-IV (DPP-IV), and CD26 expression in mononuclear cells (MNC) while reducing insulin, C-peptide, proinsulin, GIP, and GLP-1 concentrations. Ten healthy normal subjects were given either a 910-calorie HFHC meal or an American Heart Association (AHA) meal rich in fruit and fiber during the first visit and the other meal during the second visit in crossover design. Blood samples were collected at baseline and at 15, 30, 45, 60, 75, 90, 120, 180, and 300 min following the meal. There was a significantly greater increase in glucose concentrations and lower increase in postprandial insulin, C-peptide, and proinsulin concentrations and lower insulin/glucose ratios following the HFHC meal. HFHC meal intake induced marked increases in plasma glucagon and DPP-IV concentrations and an increase in CD26 mRNA expression in MNC compared with the AHA meal. In addition, the HFHC meal induced a reduction in GIP and peak GLP-1 secretion compared with the AHA meal. This was associated with a significantly greater increase in oxidative stress and proinflammatory mediators including, ROS generation, TNFα, and IL-1β mRNA expression and plasma concentrations of TBARS, FFA, and LPS. We conclude that the proinflammatory HFHC meals result in lower insulin, C-peptide, proinsulin, and GIP secretion in association with higher plasma glucagon and DPP-IV concentrations and CD26 expression in MNC compared with the AHA meal.