saturated fat and genetic obesity risk
June 5, 2014

For Those Genetically Predisposed To Obesity, Limiting Saturated Fats Might Be Necessary

April Flowers for - Your Universe Online

Many advertisements today talk about what kind of fats are in their products. Dietary fats come in three main varieties: unsaturated, saturated and trans. Your body can't operate correctly without dietary fat, but how much of which kind is right? The Mayo Clinic reports that one main concern with dietary fats is the high caloric content, and the role they might play in conditions such as type 2 diabetes and obesity.

A new study from the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University reveals that limiting saturated fat could help people whose genetic makeup increases their chance of being obese.

The study, published in a recent issue of the Journal of the Academy of Nutrition and Dietetics, identified 63 gene variants related to obesity. The research team analyzed the gene variants to calculate a genetic risk score for obesity for over 2,800 men and women in the US. The study subjects were participating in two large studies on heart disease prevention. They found that individuals with a higher genetic risk score for obesity and who consumed more of their calories as saturated fats, were more likely to have a higher Body Mass Index (BMI) than those who didn't. The researchers accounted for confounding factors such as age, sex, and physical activity levels in their findings.

"We already know there are certain genes that interact with dietary fat and affect BMI," said José M. Ordovás, Ph.D., director of the Nutrition and Genomics Laboratory at the USDA HNRCA and a professor at the Friedman School of Nutrition Science and Policy at Tufts University. "In the current study, we analyzed dozens of variants of those genes and other genes frequently associated with obesity risk and saw that, while total fat intake was related to higher BMI, people who were genetically predisposed to obesity and ate the most saturated fat had the highest BMIs."

People whose genetic variants predispose them to obesity might be more sensitive to saturated fats, according to the research team. Saturated fats are found in food such as fatty cuts of beef and pork, butter, cheese and other high-fat dairy products.

"Little is known about the mechanisms that might explain the role of saturated fat intake in obesity," said Ordovás, who is also a member of the Genetics and Pharmacology & Experimental Therapeutics graduate program faculty at the Sackler School of Graduate Biomedical Sciences at Tufts University. "Some clinical models suggest that saturated fat might interfere with activity in the part of the brain that lets us know we're full, in addition to a few studies in people that suggest a diet high in saturated fat interferes with satiety. More research is needed to know whether those findings would also apply to gene function."

Clinicians could use genetic risk scores to personalize dietary recommendations for patients with a predisposition for obesity. "If further research can clarify a relationship between obesity related genes and saturated fat, people with higher scores would have even more incentive to follow advice to limit their saturated fat intake as part of an obesity prevention strategy," Ordovás said.