Are Omega-3 Fatty Acids A Magic Potion?

Abstract

Omega-3 polyunsaturated fatty acids have been recognized to exert favorable effects on the risk reduction of atherosclerotic cardiovascular disease (ASCVD) in many clinical trials. The mechanism is mainly attributable to their triglyceride-lowering and anti-inflammatory functions. In the JELIS trial, ASCVD risks were reduced by additionally administering eicosapentaenoic acid (EPA, 1.8 g/day) to the patients taking statins 1) . As a result, the administration of EPA to high-risk patients is now recommended to reduce ASCVD risks, such as heart attacks and strokes, in a variety of guidelines. Furthermore, recent results of the REDUCE-IT trial, which showed that additional administration of 4 g/ day EPA to statin-treated patients with high ASCVD risks reduced major cardiovascular events by 25%, were shocking worldwide 2) . In contrast, the STRENGTH trial, which verified the effects of 4 g/ day of EPA (75%), and docosahexaenoic acid (DHA, 25%) administration in patients with moderate-high ASCVD risks, did not prove any significant beneficial effect on ASCVD risks 3) . Thus, the effects of omega-3 fatty acids remain controversial. The reasons for these discrepancies are often explained by factors such as the difference in cardiovascular risks in the study population, active oils (EPA alone vs. EPA/DHA), doses and blood concentrations of fatty acids, type of control oil or comparator oils, and the presence or absence of concomitant use of statins 4) .In this issue of the Journal of Atherosclerosis and Thrombosis, Nakao et al. provided clues for solving some of the issues mentioned above. They investigated the dose-dependent atheroprotective effect of EPA/ DHA in statin-treated patients with coronary artery disease (CAD) whose serum low-density lipoprotein cholesterol level is ＜100 mg/dL 5) .