New beneficial effects of alkali‐extracted rice protein in type 2 diabetic Goto‐Kakizaki rats

Abstract

The number of type 2 diabetes mellitus (T2DM) patients is rapidly increasing and is becoming a serious problem all over the world. T2DM is a metabolic disease caused by lifestyle factors, and may lead to many complications such as chronic renal failure. Diet therapy is an important treatment to delay the progression of T2DM. Rice is a staple food as a major source of not only energy but also protein. Therefore, we focused on effects of alkali‐extracted rice protein (AE‐RP) on T2DM, especially diabetic nephropathy. AE‐RP used included high crude protein content (>90%). Male non‐obese type 2 diabetic Goto‐Kakizaki (GK) rats were fed high sucrose diets for 10 or 15 wk with 20% casein (C) or AE‐RP. The diabetic‐related markers in the blood, urine, liver and kidney were determined. The kidney tissue sections were obtained for histological analysis. AE‐RP had no effects on fasting blood glucose levels. However, the levels of plasma alkali phosphatase and urinary albumin in GK rats fed AE‐RP were significantly lower than those of C group. Renal glomerular damages were significantly higher in C group, but those in AE‐RP group were similar to those in Wistar rats fed high sucrose C diets. These results suggest that AE‐RP has a suppressive effect on progression of T2DM and diabetic nephropathy. This study was supported in part by a Grant‐in‐Aid for Scientific Research to RW from the Japan Society for the Promotion of Science.