Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease
Cochrane systematic review update (86 RCTs, 162,796 participants) finding little or no effect of long-chain omega-3 supplementation on all-cause mortality, modest signals for cardiovascular mortality and coronary events, and high-certainty triglyceride lowering (~15% relative reduction, dose-dependent).
Design
RCTs ≥12 months comparing higher vs lower intake of long-chain omega-3 (LCn3) from supplements, enriched foods, or dietary advice, versus placebo or usual intake; separate analyses for ALA plant omega-3.
Headline pooled results (LCn3)
- All-cause mortality: RR 0.97 (95% CI 0.93–1.01) — high-certainty evidence of little to no effect.
- Cardiovascular mortality: RR 0.92 (95% CI 0.86–0.99) — moderate-certainty evidence of a small relative reduction.
- Coronary heart disease events: RR 0.91 (95% CI 0.85–0.97) — low-certainty evidence of possible reduction (review-reported NNTB context).
- Fasting triglycerides: ~15% lower with increased LCn3 versus control — high-certainty, dose-dependent pattern in supplement-heavy evidence.
Interpretation for readers
This is the broadest RCT-based canvas for population-level omega-3 supplementation; it can coexist with smaller positive trials in hypertriglyceridemia or specific drug formulations because inclusion criteria and comparators differ.
Distinction
Mechanistic reviews on resolvins (e.g., Calder narrative) explain biology; this review quantifies hard endpoints and lipids across many trials.
Outcomes
- All-Cause Mortality RiskLCn3 vs control: RR 0.97 (95% CI 0.93–1.01) for all-cause mortality — high-certainty evidence of little to no benefit across 86 RCTs
- Cardiovascular Mortality RateLCn3 vs control: RR 0.92 (95% CI 0.86–0.99) for cardiovascular mortality — moderate-certainty small relative reduction