This review details the independent effects of purified eicosapentaenoic acid and docosahexaenoic acid on cardiovascular risk factors in humans. We report data from the recent literature and our own controlled clinical trials which compared the independent effects of these fatty acids in individuals at increased risk of cardiovascular disease, namely overweight hyperlipidaemic men and treated-hypertensive, type 2 diabetic men and women. We discuss the biological effects of these fatty acids and the potential mechanisms through which they may affect cardiovascular disease risk factors.
A cardioprotective effect for ω3 fatty acids is supported by prospective studies demonstrating an inverse association between fish intake and coronary heart disease mortality. Data from secondary prevention trials support a reduction in ventricular fibrillation as a primary mechanism for the decreased incidence of myocardial infarction. Clinical trials and experimental studies have shown that ω3 fatty acids have many other potentially important antiatherogenic and antithrombotic effects. Omega-3 fatty acids lower blood pressure and heart rate, improve dyslipidaemia, reduce inflammation, and improve vascular and platelet function. These favourable effects have until recently been primarily attributed to the ω3 fatty acid eicosapentaenoic acid, which is present in large amounts in fish oil. Controlled studies in humans now demonstrate that docosahexaenoic acid, although often present in lower quantities, has equally important anti-arrhythmic, anti-thrombotic and anti-atherogenic effects.
Available evidence strongly suggests that eicosapentaenoic acid and docosahexaenoic acid have differing haemodynamic and anti-atherogenic properties. The effects of the two fatty acids may also differ depending on the target population.
aSchool of Medicine and Pharmacology, Royal Perth Hospital Unit, University of Western Australia
bCardiovascular Research Centre
cSchool of Public Health, Curtin University of Technology, Perth, Western Australia, Australia
Correspondence to Dr Trevor A. Mori, School of Medicine and Pharmacology, University of Western Australia, Medical Research Foundation Building, Box X 2213 GPO, Perth, Western Australia 6847, Australia Tel: +61 8 9224 0273; fax: +61 8 9224 0246; e-mail: Trevor.Mori@uwa.edu.au
Sponsorship: Studies carried out in the laboratory of the authors were supported by grants from the National Health and Medical Research Council of Australia, the West Australian Health Promotion Foundation (Healthway) and the Royal Perth Hospital Medical Research Foundation. Purified EPA, DHA and olive oil capsules were kindly provided by the Fish Oil Test Materials Program and the US National Institutes of Health.