Efficacy of omega-3 PUFAs in depression: A meta-analysis.
Level 1 - systematic review of randomized trials
Meta-analysis of double-blind randomized placebo-controlled trials
PubMed 31383846 · doi:10.1038/s41398-019-0515-5
What was done
A systematic review and meta-analysis of double-blind randomized placebo-controlled trials was conducted searching PubMed and EMBASE through December 20, 2017. The analysis evaluated the efficacy of omega-3 polyunsaturated fatty acids (PUFAs), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on depression symptoms. Effect sizes were pooled using fixed- or random-effects models, accompanied by sensitivity analyses and publication bias assessments (Egger's test and funnel plots). The review synthesized data from 26 studies involving 2,160 participants.
What was found
Omega-3 PUFAs produced an overall reduction in depression symptoms compared to placebo (standardized mean difference [SMD] = -0.28, P = 0.004). Subgroup analyses revealed that formulations with pure EPA (100% EPA) and EPA-major content (≥60% EPA) demonstrated benefits at daily doses ≤1 g/d (SMD = -0.50, P = 0.003; and SMD = -1.03, P = 0.03, respectively). In contrast, DHA-pure and DHA-major formulations did not show significant clinical benefits over placebo.
Why it matters
This study delineates the distinct therapeutic roles of EPA versus DHA, indicating that depression benefits are largely driven by EPA-predominant formulations at or below 1 g/day.
Limits
The literature search ended in late 2017. The abstract does not specify participant depression severity, diagnostic criteria, treatment durations, or concomitant antidepressant use across included trials. In addition, optimal dose-response curves and outcomes in specific subgroups (such as patients with elevated inflammation) were not established.
Cited by
- supports For psychiatric conditions like ADHD and depression, EPA is the beneficial omega-3 fatty acid, while DHA is ineffective.