White Rice, Brown Rice, and Risk of Type 2 Diabetes in US Men and Women

Abstract

Rice has been a staple food in Asian countries for centuries. By the 20th century, the advance of grain-processing technology made large-scale production of refined grains possible.¹Through refining processes, the outer bran and germ portions of intact rice grains (ie, brown rice) are removed to produce white rice that primarily consists of starchy endosperm. Although findings are not entirely consistent, consumption of white rice, in general, generates a stronger postprandial blood glucose response as measured by the glycemic index (GI) than the same amount of brown rice. A systematic review found that the mean (SD) GI was 64 (7) for white rice and 55 (5) for brown rice.² Higher dietary GI has been consistently associated with elevated risk of type 2 diabetes (T2D) in prospective cohort studies.^3-6 In addition, brown rice consumption may impart beneficial effects on T2D risk by virtue of its high content of multiple nutrients, such as fiber, vitamins, and minerals, the majority of which are lost during refining and milling processes.⁷ In line with these observations, high intake of white rice was associated with a monotonically elevated risk of developing T2D in a Chinese population, in which white rice consumption was the primary source of carbohydrate (74% of dietary glycemic load).⁶