Inhibition of Impaired Glucose Tolerance by Sake Lees in the Type 2 Diabetic Mouse Strain KK-Ay

Abstract

Sake lees, a byproduct of the sake brewing process generated after pressing, is mostly disposed of as industrial waste. However, sake lees not only contains rice-derived components but also yeast and koji mold components and their metabolites. These are highly nutritious and have been reported to have various physiological functions. In this study, we examined the effects of mixing freeze-dried sake lees into the diet of model mice with type 2 diabetes. Mice fed with the sake lees-mixed diet for 40 days showed lower serum glucose levels than the control group. The results of the oral glucose tolerance test performed on the sake lees-fed mice showed a decrease in the diabetic phenotype characterized by a decrease in serum insulin levels and a significant increase in serum adiponectin levels. Furthermore, the expression of glucose transporter 4 mRNA in skeletal muscles was increased significantly in the sake lees-mixed diet group. These results suggest that consumption of freeze-dried sake lees may improve impaired glucose tolerance in patients with type 2 diabetes.