Replacing white rice with pre-germinated brown rice mildly ameliorates hyperglycemia and imbalance of adipocytokine levels in type 2 diabetes model rats.

Pre-germinated brown rice (PR) has been developed industrially in order to enhance the nutritional functions of its source material, brown rice (BR). The present study was aimed at clarifying the effect of PR on the type 2 diabetes mellitus. We employed Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a model of type-2 diabetes mellitus. OLETF rats were fed on either PR or white rice (WR) from the age of 4 to 35 wk. Age-matched male Long-Evans Tokushima Otsuka (LETO) rats as a non-diabetic control were also fed on WR. The HbA(1c) level in OLETF rats was significantly higher than that in LETO rats. However, the level was lower in PR-fed OLETF rats than in WR-fed OLETF rats. The plasma concentrations of TNF-α and PAI-1 in OLETF rats were higher than those in LETO rats. However, both elevated levels were decreased by the PR-feeding, but not by the WR-feeding. On the other hand, the plasma adiponectin concentration in OLETF rats was lower than that in LETO rats. The decrease in adiponectin level of OLETF rats was ameliorated by PR-feeding. The size of adipocytes in PR-fed OLETF rats was smaller than that in WR-fed OLETF rats. In summary, intake of PR instead of WR ameliorates both insulin resistance and imbalance of the levels of plasma adipocytokines leading to diabetic complications.

Insoluble fiber is a major constituent responsible for lowering the post-prandial blood glucose concentration in the pre-germinated brown rice.

The intake of pre-germinated brown rice (PR) instead of white rice (WR) ameliorates the hyperglycemia. To clarify the mechanism(s) to decrease the post-prandial blood glucose concentration, the effect of water-soluble/oil-soluble fraction-depleted PR bran (termed as "DB"; which is destarched and defatted PR bran) on post-prandial blood glucose was compared with that of full-fat PR bran (PB) or WR. The test diets, WR diet, PB diet and DB diet which are containing identical amount of available carbohydrate (1.5 g) were fed to Wistar strain rats. Post-prandial blood glucose concentration and incremental area under the curve (IAUC) for DB diet were lower than those for WR diet, and there was no difference between the DB diet and PB diet. Changes in plasma insulin concentration and the IAUC obtained also revealed the same tendency as those observed in blood glucose concentration. These results indicate that the blood glucose-lowering effect of PB diet may be derived from the properties of PB involving substantially higher content of dietary fiber than WR, and that the potential benefit of intake of PR instead of WR in the prevention of diabetic vascular complications.