A study published in The American Journal of Clinical Nutrition shows that people who consume several servings of whole grains per day while limiting daily intake of refined grains may 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.
The researchers 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,” said co-author Paul Jacques, Director of the Nutritional Epidemiology Program at the USDA HNRCA and Professor at the Friedman School of Nutrition Science and Policy at Tufts.
The researchers found that 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. Additionally, the researchers observed that participants who consumed, on average, three daily servings of whole grains but continued to eat many refined grains did not demonstrate lower VAT volume. This result implies that it is important to make substitutions in the diet, rather than simply adding whole grain foods.
The researchers note that because the studies are observational, future research that specifically investigates whole grain intake and body fat distribution in a larger, more diverse study population is needed to identify the mechanism that is driving this relationship.