Research uncovers another cause of heart disease

People who carry a gene variant that regulates the metabolism of fat in the blood may raise their risk for heart disease if their diets are laden with omega-6 fatty acids, which are found in meats and processed foods made with corn and soy oils.

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In their study involving 2,000 participants in the Framingham Heart Study, researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) found that 13 percent of men and women carried the variant of the apolipoprotein A5 (APOA5) gene. Those whose daily diets contained more than six percent of calories from foods containing omega-6 fatty acids had blood lipid profiles that made them more prone to atherosclerosis (hardening of the arteries) and heart disease, including higher triglyceride levels. The study was published in Circulation.

“Previous research points to polyunsaturated fatty acids like omega-3s and omega-6s as ‘good’ fats, thought to reduce the risk of heart disease by lowering cholesterol levels if used in place of saturated fats that are mostly found in animal sources,” said senior study author Jose Ordovas, director of the HNRCA Nutrition and Genomics Laboratory.

Omega-6s and omega-3s are known as essential fatty acids, but they have to be derived from the diet because our bodies don’t produce them. Most Americans consume about 10 times more omega-6s than omega-3s, according to the National Institutes of Health. 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 and vegetable oils like corn and soy.

However, Ordovas noted, current research has not yet found “if there is an optimal ratio for omega-3s to omega-6s, or if consuming a certain amount of omega-6s might negate the benefits of omega-3s.” But for the 13 percent who are carriers of the APOA5 gene variant, he said, consuming fewer omega-6s in relation to omega-3s may be important in helping reduce the risk of heart disease.

In the study, the carriers of the variant who ate more than six percent of total calories from omega-6s had a 21 percent increase in triglyceride levels and a 34 percent elevation of certain atherogenic lipoprotein particles in the blood.

However, consumption of omega-3s decreased triglyceride and atherogenic lipoprotein particle levels in the blood, regardless of a person’s APOA5 gene variant.

Further research may lead to the development of personalized dietary recommendations for people with the gene variant, the study concludes.