Fish Oil Supplements for Prevention of Cardiovascular Disease: The Jury Is Still Out: CON: Fish Oil is Useful to Prevent or Treat Cardiovascular Disease

Abstract

Consumption of oily fish high in omega-3 fatty acids (n-3FAs) is strongly associated with reduced risk of adverse cardiovascular events. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the n-3FAs in fish oil believed to confer its beneficial effects. Over the past two decades, multiple clinical trials have been conducted to test the hypothesis that encapsulated EPA and DHA supplements improve cardiovascular outcomes in patients with established cardiovascular disease or at risk of developing it. Over the same time period, over-the-counter fish oil supplements have become a multi-billion-dollar industry. In this article, we briefly review available clinical trial data involving EPA and DHA supplementation. Based on currently available information, we conclude that combination capsules containing EPA and DHA should not be used to reduce cardiovascular risk. Some studies suggest that EPA as stand-alone therapy decreases cardiovascular risk. Nevertheless, we advocate a restrictive approach to using EPA to improve cardiovascular outcomes.

Figure 1

Classification of fatty acids. All fatty acids consist of a hydrocarbon backbone attached to a carboxyl group (−COOH) and can be classified according to the absence or presence of doublebonds in their backbone (i.e., saturated or unsaturated, respectively). N-3 polyunsaturated fatty acids can be plant derived, such as alpha linolenic acid (ALA), or marine-derived, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).