Blood glucose lowering effects of brown rice in normal and diabetic subjects

Abstract

Carbohydrate foods, which produce low glycemic responses, have been shown to be beneficial in the dietary management of chronic diseases such as diabetes and hyperlipidemia. This study determined the starch digestion rate in vitro and, in a randomised crossover design, the postprandial blood glucose response of 10 healthy and nine type 2 diabetic volunteers to brown rice compared to milled rice from the same batch and variety. The total sugar released in vitro was 23.7% lower in brown rice than in milled rice. In healthy volunteers, the glycemic area and glycemic index were, respectively, 19.8% and 12.1% lower (p < 0.05) in brown rice than milled rice, while in diabetics, the respective values were 35.2% and 35.6% lower. The effect was partly due to the higher amounts of phytic acid, polyphenols, dietary fiber and oil in brown compared to milled rice and the difference in some physicochemical properties of the rice samples such as minimum cooking time and degree of gelatinisation. In conclusion, brown rice is a more health beneficial food for diabetics and hyperglycemic individuals than milled rice.