Dietary polyunsaturated fat intake in coronary heart disease risk

Abstract

Several dietary guidelines suggest replacing saturated fatty acids with polyunsaturated fatty acids in the diet, in order to prevent cardiovascular disease. This means replacing the major sources of saturated fat, such as meat and dairy, with foods that are rich in n-3 polyunsaturated fatty acids (fish and other seafood, linseed, rapeseed oil) and n-6 polyunsaturated fatty acids (vegetable oils, nuts, seeds). The recommendations are largely based on the beneficial impact of the polyunsaturated fatty acids on serum lipids, especially on LDL [1], but polyunsaturated fatty acids may also have beneficial effects on other cardiovascular disease risk factors, such as on blood pressure and vascular function [2], insulin resistance [3] and, especially in the case of the long-chain n-3 polyunsaturated fatty acids from fish, on ventricular arrhythmias [4]. The recommendations are also supported by the findings from prospective cohort stud ies that suggest that replacing saturated fatty acids with polyunsaturated fatty acids is associated with lower risk of coronary events, especially coronary death [5]. The cardioprotective effects of consuming polyunsaturated fatty acids in place of saturated fatty acids have also been investigated in dietary fat modification trials. However, the majority of these trials were conducted already in the 1960s and 1970s, and many had methodological limitations. Although there was no statistically significant effect on the coronary heart disease risk in most of the trials, a pooled analysis of the trials found a 10% lower risk of coronary heart disease with each five energy percentage higher intake of polyunsaturated fatty acids in place of saturated fatty acids [6]. Other meta-analyses based on these trials have come to various conclusions, mainly due to the choice of the included trials and the specific cardiovascular disease outcomes [7,8].