Cochrane review of omega-3 fatty acids for prevention of cardiovascular disease

Takeaway

• Moderate- and low-certainty evidence suggests that increasing long-chain omega-3 fatty acid (LCn3) intake may slightly reduce the risk for coronary heart disease (CHD) mortality and lower serum triglycerides level.
• Higher intake of alpha-linolenic acid (ALA) may slightly lower the risk for cardiovascular disease (CVD) events and arrhythmia.

Why this matters

• Guidelines recommend increasing intake of omega-3-rich foods, and sometimes supplementation but no recent trials have confirmed this.

Study design

• Cochrane review included 86 randomised clinical trials (RCTs; n=162,796) after a search across electronic databases.
• Funding: None.

Key results

• Higher intake of LCn3 showed little or no effects on:
  • all-cause mortality (RR, 0.97; 95% CI, 0.93-1.01);
  • CVD mortality (RR, 0.92; 95% CI, 0.86-0.99) and events (RR, 0.96; 95% CI, 0.92-1.01);
  • stroke (RR, 1.02; 95% CI, 0.94-1.12); and
  • arrhythmia (RR, 0.99; 95% CI, 0.92-1.06).
• Similarly, increase in intake of ALA had little or no effects on:
  • all-cause mortality (RR, 1.01; 95% CI, 0.84-1.20);
  • CVD mortality (RR, 0.96; 95% CI, 0.74-1.25); and
  • CHD mortality (RR, 0.95; 95% CI, 0.72-1.26) and events (RR, 1.00; 95% CI, 0.82-1.22).
• However, moderate- and low-certainty evidence suggested that increasing intake of LCn3 and ALA was associated slightly lower CHD mortality (RR, 0.90; 95% CI, 0.81-1.00 and  RR, 0.95; 95% CI, 0.83-1.07, respectively) and events (RR, 0.91; 95% CI, 0.85-0.97 and RR, 0.73; 95% CI, 0.55-0.97, respectively).
• Higher intake of LCn3 and ALA had little or no effect on serious adverse events, adiposity, lipids, and blood pressure but an increase in LCn3 intake reduced triglycerides level by ~15% in a dose-dependent way.

Limitations

• Risk of bias.