Cardiac physiology and clinical efficacy of dietary fish oil clarified through cellular mechanisms of omega-3 polyunsaturated fatty acids

Reduced cardiac mortality and morbidity have long been observed in association with omega-3 long chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish consumption, without clear physiological explanation. This review seeks to identify mechanisms of action based on evidence: of physiological effects, active components and effective intakes. Fish oil pleiotropic effects reveal actions that are either intrinsic: effects on cardiac function dependent upon membrane incorporation; or extrinsic: indirect cardiac effects through vascular disease. Extrinsic actions require EPA + DHA doses >3 g/day. Intrinsic effects derive from usual dietary intakes,