Pinitol from soybeans reduces postprandial blood glucose in patients with type 2 diabetes mellitus

The effect of 3-O-methyl-D-chiro-inositol (D-pinitol), purified from soybean, on the postprandial blood glucose response in patients with type 2 diabetes mellitus was examined. Fifteen Korean subjects with type 2 diabetes mellitus (seven men, eight women; 60.3 +/- 3.1 years old) ingested cooked white rice containing 50 g of available carbohydrate with or without prior ingestion of soy pinitol. Pinitol was given either as a 1.2 g dose at 0, 60, 120, or 180 minutes prior to rice ingestion, or as a 0.6 g dose at 60 minutes prior to rice ingestion. Capillary blood glucose levels were monitored for 4 hours after rice consumption. The ingestion of 1.2 g of pinitol 60 minutes prior to rice consumption controlled postprandial capillary blood glucose most effectively, significantly diminishing the postprandial increase in plasma glucose levels measured at 90 and 120 minutes after rice consumption (P < .05). The incremental area under the plasma glucose response curve for subjects who consumed both pinitol and rice was significantly lower than that for subjects who consumed only rice (P < .05), but pinitol had no apparent effect on postprandial insulin levels. Therefore, soybean-derived pinitol may be useful in controlling postprandial increases in blood glucose in patients with type 2 diabetes.