Efficacy and safety of omega-3 fatty acids supplementation on depression: a systematic review and dose-response meta-analysis of randomized controlled trials.

We aimed to investigate the effectiveness of omega-3 fatty acids supplementation on the risk of developing depression, depressive symptoms and remission of depression. We searched PubMed, Scopus, and Web of Science from inception to December 2022 to find randomized trials of omega-3 fatty acids supplementation in adults. We conducted random-effects meta-analyses to estimate standardized mean differences (SMD) and 95% confidence intervals (CIs) for continuous outcomes and risk difference and 95%CI for binary outcomes. A total of 67 trials were included. Each 1 g/d omega-3 fatty acids supplementation significantly improved depressive symptoms in adults with and without depression (moderate-certainty evidence), with a larger improvement in patients with existing depression. Dose-response analyses indicated a U shaped effect in patients with existing depression, with the greatest improvement at 1.5 g/d. The analysis showed that omega-3 fatty acid supplementation significantly increased depression remission by 19 more per 100 in patients with depression (low-certainty evidence). Supplementation with omega-3 fatty acids did not reduce the risk of developing depression among the general population, but it did improve the severity of depression among patients with existing depression.