Item #12 

Amino Acid Supplementation Triples Insulin Secretion in Type 2’s

Ingestion of the amino acid/protein mixture led to a significant increase in insulin secretory response among type 2 diabetics

The insulin response to carbohydrate consumption in patients with type 2 diabetes is greatly enhanced by co-ingestion of a free amino acid/protein mixture, according to a report in the March issue of Diabetes Care.

"Insulin secretion in response to carbohydrate intake is blunted in type 2 diabetic patients," Dr. Luc J. C. van Loon, of Maastricht University, the Netherlands, and colleagues note. "However, it is not clear whether the insulin response to other stimuli, such as amino acids, is also diminished."

The researchers examined the insulinotropic capacity of a mixture containing free leucine, phenylalanine, and a protein hydrolysate in ten patients with type 2 diabetes of 8.9 years mean duration and in ten healthy controls. Insulin responses were determined on two occasions--once following ingestion of carbohydrate alone, and later in combination with the free amino acid/protein mixture.

Compared with carbohydrate ingestion alone, co-ingestion of the amino acid/protein mixture led to a significant increase in insulin secretory response among both type 2 diabetics and control patients (189% and 114%, respectively; p < 0.01). Specifically, in the diabetic patients, insulin secretion went from 2 MU/mL over a 2-hour period after carbohydrate ingestion to 6 MU/mL per 2h after the combination test.

"Plasma glucose, glucagon, growth hormone, cortisol, insulin-like growth factor I and insulin-like growth factor binding protein 3 responses were not different between trials within the 2-h time frame," Dr. van Loon and colleagues report.

They conclude that insulin secretory capacity is underestimated in type 2 diabetics, and that nutritional interventions to improve postprandial glucose disposal warrant further study.  Diabetes Care 2003;26:625-630.