Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults

Objective This study evaluated the postprandial glycemic, insulinemic, and breath hydrogen responses to a liquid nutritional product containing Salacia oblonga extract, an herbal α-glucosidase inhibitor, and two insulinogenic amino acids. Methods In a randomized, double-masked, crossover design, 43 healthy subjects were fed the following meals on separate days after overnight fasting: control (C; 480 mL of a study beverage containing 82 g of carbohydrate, 20 g of protein, and 14 g of fat), control plus 3.5 g each of phenylalanine and leucine (AA), control plus 1000 mg of S. oblonga extract (S), and control plus S and AA (SAA). Postprandially, fingerstick capillary plasma glucose and venous serum insulin levels were measured for 180 min, and breath hydrogen excretion was measured for 480 min. Results The baseline-adjusted peak glucose response was not different across meals. However, changes in plasma glucose areas under the curve (0 to 120 min and 0 to 180 min, respectively) compared with C were −9% and −11% for AA (P > 0.05 each), −27% and −24% for S (P = 0.035 and 0.137), and −27% and −29% for SAA (P < 0.05 each). Changes in insulin areas under the curve were +5% and +5% for AA (P > 0.05 each), −35% and −36% for S (P < 0.001 each), and −6% and −7% for SAA (P > 0.05 each). Breath hydrogen excretion was 60% greater (P < 0.001) in the S-containing meals than in the C- and AA-containing meals and was associated with mild flatulence. Conclusions Salacia oblonga extract is a promising nutraceutical ingredient that decreased glycemia in this study. Supplementation with amino acids had no significant additional effect on glycemia.