Suppressive effect of a single dose of monoglucosyl rutin on postprandial blood glucose elevation: A randomized, placebo-controlled, double-blind crossover study

Objective: This study aimed to investigate the suppressive effect of a single dose of water-soluble α- glycosylated rutin (monoglucosyl rutin; MR) on postprandial blood glucose elevation in healthy subjects with relatively high fasting blood glucose levels.Methods: This randomized, placebo-controlled, double-blind crossover study enrolled 34 healthy Japanese adult subjects with relatively high fasting blood glucose levels. The study period ran from November 13, 2019, to March 19, 2020. All subjects were randomly allocated to either sequence A or sequence B (n = 17 per group) using a computerized random number generator. The washout period was at least one week between periods I and II. In period I, the subjects took either MR or placebo tablets. In period II, subjects took different tablets from the ones they had taken in period I. We evaluated their blood glucose and insulin levels after glucose loading (150 g of cooked rice). The incremental area under the curve (IAUC) of the postprandial blood glucose level was determined as the primary outcome. The blood glucose and insulin levels at maximum (maximum blood concentration; Cmax), each measurement point, and IAUC of the blood insulin level after glucose loading were the secondary outcomes.Results: Out of 33 subjects, 16 in sequence A (11 men and 5 women, 54.5 ± 9.8 years) and 17 in sequence B (9 men and 8 women, 58.8 ± 9.4 years) were analyzed as a per-protocol dataset. The glucose IAUC after MR consumption was significantly lower than that of the placebo (P = 0.034). Results of the other outcomes were not observed with significant treatment effects. There were no adverse events attributable to the test foods.Conclusions: We suggest that MR has a suppressive effect on the elevation of postprandial blood glucose in healthy adults with relatively high fasting blood glucose levels.Trial registration: UMIN-CTR: UMIN000038515. Foundation: Toyo Sugar Refining Co., Ltd.Keywords: monoglucosyl rutin, blood glucose level, incremental area under the curve, α-amylase, α-glucosidase, crossover study