Increased consumption of white rice associated with increased risk for type 2 diabetes

People who consume 5 or more servings of white rice per week appear to have an increased risk for type 2 diabetes, whereas people who consume 2 or more servings of brown rice per week have a decreased risk.

Researchers at Harvard School of Public Health and Brigham and Women’s Hospital pooled data on 39,765 men and 157,463 women without diabetes at baseline previously included in the Health Professionals Follow-Up Study (HPFS), Nurses’ Health Study I (NHS I) and Nurses’ Health Study II (NHS II) to assess the association between diabetes risk and type of rice consumed. Participants were diabetes free at original study enrollment.

There were 2,648 incident cases of type 2 diabetes during 20 years of follow-up among those included in the HPFS, 5,500 cases during 22 years among those in NHS I and 2,359 cases during 14 years among those in NHS II.

People who consumed at least 5 servings of white rice per week had a 17% increased risk for type 2 diabetes compared with people who ate 1 serving or less (95% CI, 1.02-1.36).

Conversely, people who consumed 2 or more servings of brown rice per week had a decreased risk for type 2 diabetes compared with those who ate less brown rice (RR=0.89; 95% CI, 0.81-0.97).

When the researchers assessed the replacement of 50 g of white rice per day with 50 g of brown rice per day, brown rice was consistently associated with a decreased risk for type 2 diabetes. The RR for every 50 g of brown rice intake was 0.84 (95% CI, 0.79-0.91). The RR for the replacement of 50 g of white rice with 50 g of brown rice was 0.64 (95% CI, 0.58-0.70).

Despite current U.S. Dietary Guideline recommendations for at least half of carbohydrate intake to be derived from whole grains, more than 70% of rice consumed in the United States is white, according to background information.

Sun Q. Arch Intern Med. 2010;170:961-969.