Postprandial glycemia and insulin secretion following glutamine administration: A randomized controlled trial.

Objective: The objective of the present study is to investigate the effects of glutamine administration on postprandial glycemia, insulin, and C-peptide concentration in patients with type 2 diabetes. Methods: A randomized, double-blind, placebo-controlled trial was conducted on patients with type 2 diabetes so that 33 subjects were recruited in each group. The patients were randomly allocated to receive either 30 g/d glutamine or placebo (with instructions to take in half glass of ice-cold water 5 to 10 min before each main meal) for 6 weeks. Postprandial C-peptide, insulin, and glucose were measured at the baseline and at the end of the study at 30 and 90 min after consuming a meal comprising wheat-cake and reduced fat milk. Results: The repeated measures ANOVA revealed no significant difference between the groups for glucose and insulin after 6 weeks of intervention (p > 0.05). However, C-peptide was reduced in both intervention groups at all measurement points. Between-group differences remained significant by the end of the study (p = 0.02). Conclusions: Glutamine supplementation before each main meal does not represent an effective nutritional strategy to improve postprandial glycemic control or postprandial insulin secretion in type 2 diabetes patients.