Effect Of an Amino Acid Supplement on Glucose Tolerance in Healthy Overweight Adults

Abstract

It is estimated that two-thirds of the adult population and a growing number of children in US are overweight or obese. Overweight is considered the single strongest predictor of type 2 diabetes, which is primarily characterized by insulin resistance and hyperglycemia. Amino acids, such as leucine and isoleucine, have been shown to improve blood glucose tolerance in rats. PURPOSE: To determine whether an amino acid mixture could improve the blood glucose clearance of healthy overweight men and women following an oral glucose tolerance test (OGTT). METHODS: Twenty-two overweight healthy subjects (31±2 yrs, BMI 34.6±1.1 kg/m2) completed two OGTT after consuming two different test beverages. The amino acid beverage (CHO/AA) contained 12.395g amino acid mixture consisting of isoleucine, leucine, cystine 2HCl, methionine and valine in a 12 oz solution. The control beverage (CHO) consisted of a 12 oz placebo drink. Both beverages were mixed with a 10 oz orange-flavored drink containing 100g dextrose to make a drink totaling 22 oz. Venous blood samples were drawn 10min before the drinks, and 15, 30, 60, 120 and 180min after the drinks. RESULTS: During the OGTT, the plasma glucose response for the CHO/AA treatment was significantly lower than that of the CHO treatment, which was supported by the finding that the glucose AUC for the CHO/AA treatment was significantly lower than that for the CHO treatment (806.9±31.4 vs. 942.6±40.6 mmol/L/3h, p<0.05). The plasma glucose levels were significantly lower during the CHO/AA treatment than the CHO treatment at 30, 60, 120, and 180 min post supplementation (5.4±0.2 vs. 6.3±0.2, 4.7±0.3 vs. 5.6±0.4, 4.2±0.2 vs. 4.9±0.3, 3.9±0.2 vs. 4.4±0.2 mmol/L, respectively, p<0.05). However, there were no significant differences in plasma insulin (p=0.343) and c-peptide (p=0.079) responses between treatments. A significant treatment effect was found in plasma glucagon (p<0.05). The amino acid mixture had no significant effects on plasma FFA, triglyceride, and lactate. CONCLUSION: An amino acid mixture, composed of 5 amino acids, lowers the glucose response to an OGTT in healthy overweight subjects in an insulin-independent manner. Supported by Abbott Laboratories.