Boston -- Researchers from the Jean Mayer USDA Human Nutrition Research Center (USDA HNRCA) at Tufts University and colleagues have found another link among genes, heart disease and diet. The study, published in Circulation, examined apolipoprotein A5 (APOA5), a gene that codes for a protein, which in turn plays a role in the metabolism of fats in the blood. The results show that people who carry a particular variant of APOA5 may have elevated risk factors that are associated with heart disease, but only if they also consumed high amounts of omega-6 fatty acids in their diets.
Corresponding author Chao-Qiang Lai, PhD, a USDA-Agricultural Research Service (ARS) scientist at the USDA HNRCA, and colleagues analyzed lipid levels and dietary assessment questionnaires of more than 2,000 participants in the Framingham Heart Study and quantified their intake of different types of fats.
Omega-6 fatty acids, as well as omega-3 fatty acids, are polyunsaturated fatty acids (PUFAs) and, according to a report from the National Institutes of Health Office of Dietary Supplements, most Americans consume about 10 times more omega-6s than omega-3s. Omega-3s are found in nuts, leafy green vegetables, fatty fish, and vegetable oils like canola and flaxseed, while omega-6s are found in grains, meats, vegetable oils like corn and soy, and also processed foods made with these oils. Both omega-3s and omega-6s, known as essential fatty acids, must be consumed in the diet because they are not made by the body.
"We know that some people are genetically predisposed to risk factors for heart disease, such as elevated low-density lipoprotein levels in the blood," says Lai, "and that APOA5 has an important role in lipoprotein metabolism. We wanted to determine if certain dietary factors change the role of APOA5 in metabolizing these lipoproteins and their components, such as triglycerides."