Positive Health Online

Abstract

MANGAT I, Arrhythmia Service, St Michael's Hospital, Toronto, Canada University of Toronto, Toronto, Canada.

Background

Interest in the cardiovascular protective effects of n-3 (omega-3) fatty acids has continued to evolve during the past 35 y since the original research describing the low cardiovascular event rate in Greenland Inuit was published by Dyerberg et al.

Methodology

Numerous in vitro experiments have shown that n-3 fatty acids may confer this benefit by several mechanisms: they are anti-inflammatory, anti-thrombotic, and anti-arrhythmic. The n-3 fatty acids that have received the most attention are those that are derived from a fish source: namely, the longer-chain n-3 fatty acids eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). More limited data are available on the cardiovascular effects of n-3 fatty acids derived from plants such as alpha-linolenic acid (ALA; 18:3n-3).

Results

Observational data suggest that diets rich in EPA, DHA, or ALA do reduce cardiovascular events, including myocardial infarction and sudden cardiac death; however, randomized controlled trial data are somewhat less clear. Several recent meta-analyses have suggested that dietary supplementation with EPA and DHA does not provide additive cardiovascular protection beyond standard care, but the heterogeneity of included studies may reduce the validity of their conclusions. No data exist on the potential therapeutic benefit of EPA, DHA, or ALA supplementation on those individuals who already consume a vegetarian diet.

Conclusion

Overall, there is insufficient evidence to recommend n-3 fatty acid supplementation for the purposes of cardiovascular protection; however, ongoing studies such as the Alpha Omega Trial may provide further information.

References

Mangat I. Do vegetarians have to eat fish for optimal cardiovascular protection?. American Journal of Clinical Nutrition. 89(5):1597S-1601S. May 2009.