Omega-3

Research summary

• The cardiovascular evidence for omega-3 supplementation is a useful case study in scientific nuance: a Cochrane review found little to no clear benefit for primary or secondary cardiovascular disease prevention, while a separate, larger meta-analysis of 13 randomized trials covering over 127,000 participants and dose-response analyses found modest but real reductions in cardiovascular events — the two conclusions differ mainly by which trials and doses are emphasized.
• Evidence for cognitive decline and dementia from prospective cohorts is suggestive but not conclusive.
• The mood evidence is more consistent: meta-analyses of randomized trials support a modest antidepressant effect, including in elderly patients and as an adjunct in bipolar disorder, with effects on anxiety and depression combined also supported in a more recent meta-analysis.
• Overall, omega-3's benefits appear real but modest and outcome-specific, rather than the broad cardiovascular protection sometimes claimed.