section name header

Evidence summaries

Omega-3 Fatty Acids for Prevention of Cardiovascular Disease

Long-chain omega-3 fats do not have important positive or negative effects on all-cause mortality or cardiovascular events in primary or secondary prevention. They may slightly reduce risk of coronary heart disease events. Level of evidence: "A"

Summary

A Cochrane review [Abstract] 1 included 86 studies with a total of 162 796 subjects at varying cardiovascular risk. Most studies assessed long-chain omega-3 (LCn3) supplementation with capsules, but some used LCn3- or alpha-linolenic acid (ALA)-rich or enriched foods or dietary advice compared to placebo or usual diet. LCn3 doses ranged from 0.5 g a day to more than 5 g a day (19 studies gave at least 3 g LCn3 daily).

LCn3 had no statistically significant effect on all-cause mortality (RR 0.97, 95% CI 0.93 to 1.01; 45 studies, n=143 693), cardiovascular events (RR 0.96, 95% CI 0.92 to 1.01; 43 studies, n=140 482), stroke (RR 1.02, 95% CI 0.94 to 1.12; 31studies, n=138 888), or arrhythmia (RR 0.99, 95% CI 0.92 to 1.06; 30 studies, n=77 990). LCn3 slightly reduced cardiovascular mortality (RR 0.92, 95% CI 0.86 to 0.99; 29 studies, n=117 837), coronary heart disease (CHD) mortality (RR 0.90, 95% CI 0.81 to 1.00; 24 studies, n=127 378; NNTB 334), and CHD events (RR 0.91, 95% CI 0.85 to 0.97; 32 studies, n=134 116; NNTB 167).There was little evidence of effects of eating fish.

Increasing ALA intake had no statistically significant effect on all-cause mortality, cardiovascular mortality, CHD mortality, CHD events, and cardiovascular events, but slightly reduced risk of arrhythmia (RR 0.73, 95% CI 0.55 to 0.97; 2 studies, n=4 912).

    References

    • Abdelhamid AS, Brown TJ, Brainard JS et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2020;(3):CD003177. [PubMed].

Primary/Secondary Keywords