Optimal Dose of n-3 Polyunsaturated Fatty Acids for Cardiovascular Event Prevention

Background: The n-3 polyunsaturated fatty acids (PUFA), represented by eicosapentaenoic acid (EPA) and docosahexaenoic acid, have anti-atherogenic effects (e.g., neutral fat-lowering effects) and other beneficial effects such as antiplatelet, anti-inflammatory, plaque stabilizing, vascular endothelial function ameliorative, antihypertensive, and anti-arrhythmic effects. Epidemiological studies and clinical trials have assessed the inhibitory effects of n-3 PUFA on cardiovascular events. Methods and Results: Studies that reported positive outcomes, such as the Japan EPA Lipid intervention Study (JELIS) and the Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia (REDUCE-IT), noted a tendency toward the use of high-dose n-3 PUFA (1.8–4 g/day). The Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto Miocardico-Prevenzione (GISSI-Prevenzione) trial and the JELIS had high EPA/arachidonic acid (AA) baseline ratios. In contrast, negative outcome studies, such as the Outcome Reduction with an Initial Glargine Intervention (ORIGIN) trial, Risk and Prevention study, A Study of Cardiovascular Events in Diabetes (ASCEND), and the Vitamin D and Omega-3 Trial (VITAL) had participants who tended to use low-dose n-3 PUFA (0.84–1 g/day) and to have low baseline EPA/AA. Conclusions: Differences in baseline EPA/AA ratio and the EPA/AA ratio threshold for the prevention of cardiovascular events seem to contribute to the different outcomes, together with the dose of n-3 PUFA.