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Fish oils don't cut risk of CVD

Do omega 3 fatty acids decrease mortality, cardiovascular disease or cancer in adults?

Do omega 3 fatty acids decrease mortality, cardiovascular disease or cancer in adults?


The authors of this review identified 48 randomised controlled trials and 41 cohort studies evaluating the effect of fish oil supplementation on overall mortality, cardiovascular disease and cancer in adults.

They identified these studies using the usual rigorous Cochrane methodology and analysed the results from randomised trials separately from cohort data. Omega 3 fatty acids were given either as supplements or as a recommendation to eat more oily fish.

In randomised trials with more than 30,000 patients, supplementation did not significantly reduce mortality (relative risk = 0.87; 95 per cent confidence interval 0.73-1.03) or the likelihood of a cardiovascular event (RR =1.09; 0.87-1.37).

Long-chain omega 3 fatty acids did not produce different results from short-chain fats. Cancer was neither increased nor decreased.

The lack of benefit demonstrated conflicts with the results of an earlier meta-analysis (Am J Med 2002;112:298-304). However, it is the second study published after that meta-analysis that did not find a benefit overall.

Level of evidence

1a (see

Reference Hooper L et al. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ, Apr 2006;332:752-760

Bottom line: Overall, omega 3 fatty acid supplementation does not decrease mortality or cardiovascular disease as compared with placebo. This study combined both primary and secondary prevention; that is, it included people with and without coronary heart disease.

This Patient Oriented Evidence that Matters (POEMs) is taken from InfoPOEMS/Inforetriever, a point of care evidence-based medicine tool, published by John Wiley. For more information, e-mail: or visit

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