Co-ingestion of a protein hydrolysate and amino acid mixture with carbohydrate improves plasma glucose disposal in patients with type 2 diabetes

Abstract

Background: Although insulin secretion after carbohydrate ingestion is severely impaired in patients with type 2 diabetes, amino acid and protein co-ingestion can substantially increase plasma insulin responses. Objective: We investigated insulin responses and the subsequent plasma glucose disposal rates after the ingestion of carbohydrate alone (CHO) or with a protein hydrolysate and amino acid mixture (CHO+PRO) in patients with a long-term diagnosis of type 2 diabetes. Design: Ten type 2 diabetic patients [mean (±SEM) age: 62 ± 2 y; body mass index (kg/m2): 27 ± 1] and 9 healthy control subjects (age: 58 ± 1 y; body mass index: 27 ± 1) participated in 2 trials in which the plasma insulin response was measured after the ingestion of 0.7 g carbohydrate · kg-1 · h -1 with or without 0.35 g · kg-1 · h -1 of a mixture that contained a protein hydrolysate, leucine, and phenylalanine. Continuous infusions with [6,6-2H2]glucose were then given to investigate plasma glucose disposal. Results: Plasma insulin responses were higher by 299 ± 64% and 132 ± 63% in the CHO+PRO trial than in the CHO trial in the diabetic patients and the matched control subjects, respectively (P < 0.001). The subsequent plasma glucose responses were reduced by 28 ± 6% and 33 ± 3% in the CHO+PRO trial than in the CHO trial in the diabetic patients and the matched control subjects, respectively (P < 0.001). The reduced plasma glucose response in the diabetic patients was attributed to a 13 ± 3% increase in glucose disposal (P < 0.01). Conclusions: The combined ingestion of carbohydrate with a protein hydrolysate and amino acid mixture significantly increases de novo insulin production in patients with a long-term diagnosis of type 2 diabetes. The increased insulin response stimulates plasma glucose disposal and reduces postprandial glucose concentrations. © 2005 American Society for Clinical Nutrition.