A new study has suggested that people who consume several servings of whole grains per day while limiting daily intake of refined grains appear to have less of a type of fat tissue thought to play a key role in triggering cardiovascular disease and type 2 diabetes.
Researchers at the Jean Mayer USDA Human Nutrition Researcher Center on Aging (USDA HNRCA) at Tufts University observed lower volumes of Visceral Adipose Tissue (VAT) in people who chose to eat mostly whole grains instead of refined grains.
"VAT volume was approximately 10 pc 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," first author Nicola McKeown, a scientist with the Nutritional Epidemiology Program at the USDA HNRCA, said.
"For example, a slice of 100 pc whole wheat bread or a half 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."
McKeown and colleagues, including senior author Caroline S. Fox, medical officer at The Framingham Heart Study of the National Heart Lung and Blood Institute (NHLBI), examined diet questionnaires submitted by 2,834 men and women enrolled in The Framingham Heart Offspring and Third Generation study cohorts. The participants, ages 32 to 83, underwent multidetector-computed tomography (MDCT) scans, to determine VAT and subcutaneous adipose tissue (SAT) volumes.
Visceral fat surrounds the intra-abdominal organs while subcutaneous fat is found just beneath the skin.
"Prior research suggests visceral fat is more closely tied to the development of metabolic syndrome, a cluster of risk factors including hypertension, unhealthy cholesterol levels and insulin resistance that can develop into cardiovascular disease or type 2 diabetes," explained co-author Paul Jacques, director of the Nutritional Epidemiology Program at the USDA HNRCA and a professor at the Friedman School of Nutrition Science and Policy at Tufts.
"Not surprisingly, when we compared the relationship of both visceral fat tissue and subcutaneous fat tissue to whole and refined grain intake, we saw a more striking association with visceral fat. The association persisted after we accounted for other lifestyle factors such as smoking, alcohol intake, fruit and vegetable intake, percentage of calories from fat and physical activity," Jacques added.
The finding is published in The American Journal of Clinical Nutrition.