Dietary Unsaturated Fat May Reduce Risk of Heart Disease
Fat in the diet comes in many forms, and you probably already know that some fats are better for your health than others. Omega-3 fatty acids from sources such as fish oils for example can decrease chronic inflammation known to lead to conditions such as arthritis, diabetes, and Alzheimer’s disease. But another type of polyunsaturated fat, omega-6 fatty acids, may also help decrease risk for coronary heart disease.
What exactly is a polyunsaturated fatty acid (PUFA)? Chemically, these are fatty acids that contain more than one double bond. Where that bond is located within the structure determines whether it is an omega-3, omega-6, or omega-9 fatty acid. Examples of omega-6 fatty acids include linoleic acid, arachidonic acid (AA), and gamma-linolenic acid (GLA).
Researchers at the University of Cambridge in the UK gathered data from participants in the European Prospective Investigation into Cancer (EPIC)-Norfolk which included 2,424 patients aged 40 to 79 at baseline who were followed for more than 10 years. Each completed a questionnaire on their medical history, smoking, alcohol intake, physical activity, social class and education.
Blood samples were taken and evaluated for concentrations of 22 different phospholipid fatty acids which were then grouped into one of six “families”: even-chain saturated, odd-chain saturated, omega-6 polyunsaturated, omega-3 polyunsaturated, monounsaturated, and trans-fatty acids.
Patients who had the highest plasma concentration of omega-6 PUFAs had a significantly lower risk of coronary heart disease (CHD) compared with those who had the lowest concentrations.
There was also an association between higher levels of saturated fats in the blood and an increased risk of developing cardiovascular disease, although the relationship was weaker than expected, but Kay-Tee Khaw MA MSc FRCP suggests that this could be due to “measurement errors in the dietary assessment of fat intake (due to) recall errors” among other factors such as a variability in the fatty acid composition of foods.
Past studies, including one from Maastricht University Medical Center in the Netherlands, note that exchanging saturated fats in the diet for polyunsaturated fats can decrease postprandial (after-meal) fats in the blood and reduce markers of inflammation which all reduce the risk of developing heart disease.
For example, for a heart-healthy diet, instead of butter, rich in saturated fat, substitute a polyunsaturated, trans-fat free margarine on foods for flavor. Saturated fats are also found in fatty meats (beef, pork, lamb), poultry with skin, processed meats, whole and 2% milk, and lard. Certain plant oils also contain saturated fat, such as palm and palm kernel oils, coconut oil, and cocoa butter. Instead consume lean meats such as round, sirloin and loin, remove the skin from poultry, drink skim milk, and use small amounts of PUFA vegetable oils such as olive and canola.
Khaw KT, et al. "Plasma phospholipid fatty acid concentration and incident coronary heart disease in men and women: the EPIC-Norfolk Prospective Study" PLoS Med 2012;9:e1001255.
Masson CJ, Mensink RP. “Exchanging saturated fatty acids for (n-6) polyunsaturated fatty acids in a mixed meal may decrease postprandial lipemia and markers of inflammation and endothelial activity in overweight men” J Nutr. 2011 May;141(5):816-21. Epub 2011 Mar 23.
Virginia Cooperative Extension (Virginia Tech)