Effects of long-chain omega-3 polyunsaturated fatty acids on reducing anxiety and/or depression in adults; A systematic review and meta-analysis of randomised controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 37028202 · doi:10.1016/j.plefa.2023.102572
What was done
A systematic review and random-effects meta-analysis of randomized controlled trials was conducted to evaluate the efficacy of long-chain omega-3 polyunsaturated fatty acids (EPA, DHA, and DPAn-3) in reducing anxiety and depression severity in adults, focusing on EPA/DHA ratios and dosing.
What was found
Ten RCTs comprising 1,426 participants were included. Depression severity was significantly reduced with EPA-enriched formulas containing ≥60% of total EPA+DHA (SMD: -0.36; 95% CI: -0.68, -0.05; p = 0.02; I² = 86%) and with EPA doses between ≥1 g/day and <2 g/day (SMD: -0.43; 95% CI: -0.79, -0.07; p = 0.02; I² = 88%). EPA doses ≥2 g/day showed no significant effect on depression (SMD: -0.20; 95% CI: -0.48, 0.07; p = 0.14). Only one study evaluated anxiety (showing benefit with 2.1 g/day EPA), preventing meta-analysis, and zero trials investigated DPAn-3.
Why it matters
This review highlights that EPA's antidepressant efficacy appears specific to intermediate doses (1 to <2 g/day) and high-EPA formulations (≥60%), helping explain mixed findings in earlier, broader omega-3 meta-analyses.
Limits
There was substantial statistical heterogeneity across the pooled depression analyses (I² of 86% and 88%). Visual inspection of funnel plots indicated asymmetry consistent with publication bias. Evidence for anxiety was restricted to a single trial, DPAn-3 was entirely unstudied, and the total evidence base remains limited to 10 trials.
Cited by
- supports Nutrient deficiencies such as iron deficiency, vitamin D deficiency, and low omega-3 status drive or exacerbate anxiety and depression.