Dietary n-6 polyunsaturated fatty acids and cardiovascular disease: Epidemiologic evidence

Epidemiologists have been studying the effect of n-6 polyunsaturated fatty acids (PUFAs) intake on the risk of cardiovascular disease (CVD) for many decades. Abundant evidence from prospective studies on the clinical endpoints of CVD, including cohort studies measuring n-6 PUFA intake by food frequency questionnaires and nested case-control studies using biomarkers of intake level, strongly support that higher intakes of n-6 PUFAs are associated with a lower risk of CVD. Furthermore, a significant reduction in CVD risk can be achieved when saturated fatty acids (SFAs) is replaced by n-6 PUFAs. Evidence from appropriately designed and vigorously executed randomized controlled trials support that high-PUFA (predominantly linoleic acid) and low-SFA diets, compared to high-SFA diets, reduced the risk of coronary heart disease. Overall, epidemiologic studies provide a solid evidence base of the current dietary guidelines that recommend replacing SFA by PUFA, both n-6 and n-3 PUFA, for CVD prevention.