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

Background: Because of differences in processing and nutrients, brown rice and white rice may have different effects on risk of type 2 diabetes mellitus. We examined white and brown rice consumption in relation to type 2 diabetes risk prospectively in the Health Professionals Follow-up Study and the Nurses' Health Study I and II. Methods: We prospectively ascertained and updated diet, lifestyle practices, and disease status among 39 765 men and 157 463 women in these cohorts. Results: After multivariate adjustment for age and other lifestyle and dietary risk factors, higher intake of white rice (>= 5 servings per week vs <1 per month) was associated with a higher risk of type 2 diabetes: pooled relative risk (95% confidence interval [CI)], 1.17 (1.02-1.36). In contrast, high brown rice intake (>= servings per week vs <1 per month) was associated with a lower risk of type 2 diabetes: pooled relative risk, 0.89 (95% CI, 0.81-0.97). We estimated that replacing 50 g/d (uncooked, equivalent to one-third serving per day) intake of white rice with the same amount of brown rice was associated with a 16% (95% Cl, 9%-21%) lower risk of type 2 diabetes, whereas the same replacement with whole grains as a group was associated with a 36% (30%-42%) lower diabetes risk. Conclusions: Substitution of whole grains, including brown rice, for white rice may lower risk of type 2 diabetes. These data support the recommendation that most carbohydrate intake should come from whole grains rather than refined grains to help prevent type 2 diabetes.