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

Nutrition. 2005 Jul-Aug;21(7-8):848-54. doi: 10.1016/j.nut.2004.11.018.


Objective: This study evaluated the postprandial glycemic, insulinemic, and breath hydrogen responses to a liquid nutritional product containing Salacia oblonga extract, an herbal alpha-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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Analysis of Variance
  • Area Under Curve
  • Beverages
  • Blood Glucose / drug effects
  • Blood Glucose / metabolism*
  • Breath Tests
  • Celastraceae / chemistry*
  • Cross-Over Studies
  • Double-Blind Method
  • Female
  • Flatulence / epidemiology
  • Glycoside Hydrolase Inhibitors*
  • Humans
  • Insulin / blood*
  • Leucine / administration & dosage
  • Leucine / pharmacokinetics
  • Male
  • Phenylalanine / administration & dosage
  • Phenylalanine / pharmacokinetics
  • Plant Extracts / pharmacokinetics
  • Plant Extracts / pharmacology*
  • Postprandial Period
  • alpha-Glucosidases / metabolism


  • Blood Glucose
  • Glycoside Hydrolase Inhibitors
  • Insulin
  • Plant Extracts
  • Phenylalanine
  • alpha-Glucosidases
  • Leucine