Bran intake linked to reduced heart disease
May 12, 2010
by Eric Schroeder
DALLAS — Women with type 2 diabetes who ate a diet rich in bran-containing foods had a 35% lower risk of death from cardiovascular disease and a 28% lower risk in death from all causes than women who ate the least amount of bran, according to a study in the May 10 issue of Circulation: Journal of the American Heart Association.
Bran is a component of whole grain and is considered to be rich in vitamins, minerals and fiber. The research, which was funded by the National Institutes of Health, the American Heart Association Scientist Development Award and the Boston Obesity Nutrition Research Center, showed the association held regardless of whether the bran came from eating whole grain foods or from adding bran to the diet.
“To my knowledge, this is the first study of whole grain and its components and risk of death in diabetic patients,” said Lu Qi, an assistant professor of nutrition at the Harvard School of Public Health and lead author of the report. “Patients with diabetes face two or three times the risk of cardiovascular disease and premature death compared to the general population.”
As part of the study, the researchers examined data from 7,822 women diagnosed after age 30 with type 2 diabetes. The women were enrolled in the Nurses’ Healthy Study (N.H.S.), a study of 121,700 U.S. female registered nurses that began in 1976.
The women answered questions about their diets every four years over a 26-year period. The women then were divided into five groups based on their consumption of whole grain and its components, with the women consuming the most bran at 9.73 grams (median value) per day and those with the lowest consumption at less than 0.8 grams (median value) per day.
After adjusting for age, the researchers found that the women in the top 20% for intake of whole grain, bran, germ and cereal fiber, had a lower risk for death from cardiovascular diseases such as heart attack and stroke as well as lower risk for death from all causes than women in the bottom 20%. After adjusting for a range of lifestyle factors such as smoking and physical activity, only the association with bran remained statistically significant and independent of those factors, the researchers noted.
Meanwhile, the study found women in the highest group for added bran had a 55% lower risk for death from all causes and a 64% lower risk for cardiovascular death than those who ate no added bran.
“These findings suggest a potential benefit of whole grain, and particularly bran, in reducing death and cardiovascular risk in diabetic patients,” Dr. Qi said.
Although the study did not detail why whole grains and bran were beneficial, Dr. Qi said earlier research has shown high intakes of whole grain and its components might protect against systemic inflammation and dysfunction of the endothelium, which plays an important role in blood pressure regulation.
“Diabetes is thought to be a chronic state of inflammation characterized by moderately increased levels of chemical markets for inflammation and endothelial dysfunction,” Dr. Qi said. “Those markers have been found to be related to increased risk of C.V.D. in both diabetic and non-diabetic populations. In our previous studies, we have reported that intakes of whole grains and subcomponents such as cereal fiber may lower these markers in diabetic patients.”