WASHINGTON — New research from scientists at the Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging at Tufts University suggests people who eat whole grains instead of enriched grains may be less susceptible to cardiovascular disease and type 2 diabetes. The study appeared on The American Journal of Clinical Nutrition’s web site on Sept. 29 and in the November print edition.
Nicola McKeown, a scientist with the Nutritional Epidemiology Program at the U.S.D.A. Human Nutrition Research Center, said scientists observed lower volumes of visceral adipose tissue (VAT) in people who ate mostly whole grains. Visceral fat, also known as “belly fat,” has been found to be associated with the development of metabolic syndrome, a cluster of symptoms including hypertension, unhealthy cholesterol levels and insulin resistance, which may develop into cardiovascular disease or Type 2 diabetes.
The study examined diet questionnaires submitted by 2,834 men and women ages 32 to 83 enrolled in The Framingham Heart Offspring and Third Generation study cohorts.
“VAT volume was approximately 10% lower in adults who reported eating three or more daily servings of whole grains and who limited their intake of refined grains to less than one serving per day,” Ms. McKeown said. “For example, a slice of 100% whole wheat bread or half a cup of oatmeal constituted one serving of whole grains and a slice of white bread or a half cup of white rice represented a serving of refined grains.”
The researchers noted that just eating more whole grains was not enough to reduce risks, though. They found people who ate lots of whole grains didn’t have the same benefits if people also consumed a lot of refined grains as well.
“Whole grain consumption did not appear to improve VAT volume if refined grain intake exceeded four or more servings per day,” Ms. McKeown said. “This result implies that it is important to make substitutions in the diet, rather than simply adding whole grain foods. For example, choosing to cook with brown rice instead of white or making a sandwich with whole grain bread instead of white bread.”
In addition, the researchers noted the study only shows an association, and more work in a larger, more diverse population will be needed to confirm the findings.
The study was funded by the National Heart Lung and Blood Institute, the U.S.D.A. and a research grant from the General Mills Bell Institute of Health and Nutrition.