The aim of the present study was to confirm the effects of a commercially available mung bean protein isolate (GLUCODIA™) on glucose and lipid metabolism. The main component of GLUCODIA™ is 8S globulin, which constitutes 80 % of the total protein. The overall structure of this protein closely resembles soyabean β-conglycinin, which accounts for 20 % of total soya protein (soya protein isolate; SPI). Many physiological beneficial effects of β-conglycinin have been reported. GLUCODIA™ is expected to produce beneficial effects with fewer intakes than SPI. We conducted two independent double-blind, placebo-controlled clinical studies. In the first (preliminary dose decision trial) study, mung bean protein was shown to exert physiological beneficial effects when 3·0 g were ingested per d. In the second (main clinical trial) study, mung bean protein isolate did not lower plasma glucose levels, although the mean insulin level decreased with consumption of mung bean protein. The homeostatic model assessment of insulin resistance (HOMA-IR) values significantly decreased with mung bean protein. The mean TAG level significantly decreased with consumption of mung bean protein isolate. A significant increase in serum adiponectin levels and improvement in liver function enzymes were observed. These findings suggest that GLUCODIA™ could be useful in the prevention of insulin resistance and visceral fat accumulation, which are known to trigger the metabolic syndrome, and in the prevention of liver function decline.

Background: The main component of mung bean protein, accounting for more than 80%, is 8Sα globulin. Its structure closely resembles that of soybean β-conglycinin. Thereby, the mung bean protein is expected to have similar physiological effects to those of β-conglycinin, but there is no clinical evidence for these effects.Purpose of this study: The aim of this study was to confirm the positive effects of mung bean protein (GLUCODIATM) on glucose metabolism in clinical trials.Method: This clinical study was conducted using a double-blind placebo-controlled design with 45 prediabetes patients.Results: Many of the subjects were pre-diabetes with blood glucose levels exceeding 140 mg/dL by 2-hour plasma glucose level. However, the initial mean fasting plasma glucose level was less than 100 mg/dL. Therefore, mung bean protein did not lower fasting plasma glucose levels. The test period extended from summer to autumn, and increased fasting plasma glucose levels in the placebo group were observed due to seasonal factors. However, this increase was suppressed in the test group. Similarly, the mean insulin level increased in the placebo group, but the increase was also suppressed in the test group. Among obese subjects with a high body mass index, significant increases in fasting plasma glucose and insulin levels in the placebo group were observed. In the comparison between the test and the placebo groups with the average elevation value, there was a significant difference in fasting blood glucose level and significant tendencies in insulin level and homeostatic model assessment for insulin resistance value between the two groups.Conclusion: Mung bean protein suppresses fasting plasma glucose and insulin levels. Consequently, it may have an inhibitory effect on insulin resistance, a trigger of metabolic syndrome.Key words: mung bean protein, insulin, obesity, body mass index, randomized clinical trial, seasonal variation.