Need to know:

The use of omega-3 polyunsaturated fatty acid supplementation to improve cardiovascular outcomes remains a point of great clinical confusion. Recently, two large randomised trials showed discordant findings regarding the overall benefits of omega-3 supplementation.

This article will review the current evidence regarding supplementation and cardiovascular outcomes, examine the possible reasons for the discrepant results, and discuss the potential use of the omega-3 index to guide management, particularly for patients requiring secondary prevention.

Omega-3 fatty acids (O3FAs) are essential fatty acids that depend almost entirely on oral intake, with very little production within the body. In humans, the main sources of O3FA are plant-derived alpha-linolenic acid (ALA) and the mostly seafood-derived eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. EPA and DHA are associated with reductions in the risk of cardiovascular event via triglyceride lowering, antithrombotic, anti-inflammatory, membrane stabilisation and antiarrhythmic mechanisms.¹