Single-Dose Pinitol Ingestion Suppresses Post-Prandial Glucose Levels: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Limited studies have demonstrated that chronic consumption of pinitol improved glucose tolerance, and single-dose ingestion (0.6 g) 60 minutes prior to meals suppressed postprandial glucose levels in patients with type 2 diabetes mellitus. However, higher doses (6 g) were required in healthy people who ingested pinitol with a meal. This randomized, double-blind, placebo-controlled, crossover trial was conducted to clarify the effect of 0.6 g of pinitol with a meal on postprandial blood glucose levels in healthy adults. Twenty volunteers aged 18 to 25 years participated in this study. Participants visited the laboratory after an overnight fast. After measuring fasting blood glucose levels (FBG), they consumed test food (0.6 g of pinitol or placebo) and then ate breakfast (577 kcal; protein 14.0 g; fat 5.6 g; and carbohydrate 117.7 g). Blood glucose levels were measured immediately after eating and at 30, 60, 90, and 120 minutes after breakfast. Participants' mean FBG level was 102.6 +/- 8.2 mg/dL. Participants were categorized by their FBG as normal (n = 5; <= 99 mg/dL) or impaired glucose tolerance (IGT) (n = 15; 100-125 mg/dL). The incremental area under the curve of blood glucose over 120 minutes after the meal was significantly suppressed by pinitol in the IGT group (P < 0.05), but not in the normal group. Therefore, pinitol was considered to maintain postprandial blood glucose levels in healthy people with IGT, and may contribute to the prevention of type 2 diabetes.