MONDAY, May 10, 2010 (HealthDay News) -- Women with diabetes who ate a diet rich in bran-containing foods had a significantly lower death rate in a long-term study, researchers report.
"Many studies before have found some protective effect in the general population," said Dr. Lu Qi, an assistant professor of nutrition at the Harvard School of Public Health and lead author of a report in the May 10 issue of Circulation. "Our study is the first in diabetic patients, and it provides direct evidence that whole grain, especially bran, reduces total mortality and cardiovascular mortality in diabetic patients."
Bran is the hard, fiber-rich outer layer of grains such as wheat and oats. It is often removed when those grains are processed.
Though the report used data from the Nurses Health Study, which included only women, there is no reason to doubt that the same protective effect occurs in men, Qi said. He and his colleagues now are doing a similar analysis of data from a men-only study to prove that point.
The new report covered 7,822 women diagnosed with type 2 diabetes, the kind that generally develops in the adult years as the body loses its ability to metabolize blood sugar. The women answered questions about their diets every four years.
Over the 26 years covered by the study, the women in the top 20 percent for intake of whole grain, which includes bran and fiber, had a 35 percent lower risk for death from cardiovascular diseases such as heart attack and stroke and a 28 percent lower risk for death from all causes than women in the bottom 20 percent.
Medical organizations such as the American Heart Association and the American Diabetes Association have long recommended diets rich in whole-grain, high-fiber foods. "Our data strongly supports those recommendations," Qi said. "We should recommend increased intake of whole grain for diabetic patients."
The study results pointed mainly to bran intake as the protective factor. Women in the highest group for added bran had a 55 percent lower risk for death from all causes and a 64 percent lower risk for cardiovascular death than those who ate no added bran.
The new study did not look at the reason why whole grains and bran were protective, but previous research has found lower levels of inflammatory biomarkers associated with them, Qi said. Whole grains appear to reduce inflammation and improve the function of the endothelium, the thin layer of cells that line the interior of blood vessels and play an important role in regulating blood pressure.
"We do recommend that, when people with diabetes choose a grain product, they should choose a whole-grain product," said Stephanie Dunbar, a dietician who is director of clinical affairs at the American Diabetes Association. "It should be brown rice instead of white rice, whole-wheat bread rather than white bread."
People with diabetes are also advised to limit their intake of carbohydrates, which means that "their best choices are low-fat dairy products, fruits and starchy vegetables," Dunbar said. "If choosing a grain product, they should choose a whole-grain, which has more fiber and all of those good things."
Advice on diet for people with type 2 diabetes is available from the U.S. National Library of Medicine.