Efficacy of omega-3 PUFAs in depression: A meta-analysis

Abstract

We conducted this meta-analysis of double-blind randomized placebo-controlled trials to estimate the efficacy of omega-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), in the improvement of depression. We applied a systematic bibliographic search in PubMed and EMBASE for articles published prior to 20 December 2017. This meta-analysis was performed using RevMan 5.3 and R 3.4.3, and means and standard deviations were calculated in fixed- or random-effects models based on the results of the Q-test. A sensitivity analysis was also conducted to evaluate the stability of the results, and publication bias was evaluated by a funnel plot and Egger's linear regression analysis. Our search resulted in 180 articles; we analyzed 26 studies, which included 2160 participants. The meta-analysis showed an overall beneficial effect of omega-3 polyunsaturated fatty acids on depression symptoms (SMD = -0.28, P = 0.004). Compared with placebo, EPA-pure (=100% EPA) and EPA-major formulations (≥60% EPA) demonstrated clinical benefits with an EPA dosage ≤1 g/d (SMD = -0.50, P = 0.003, and SMD = -1.03, P = 0.03, respectively), whereas DHA-pure and DHA-major formulations did not exhibit such benefits.Current evidence supports the finding that omega-3 PUFAs with EPA ≥ 60% at a dosage of ≤1 g/d would have beneficial effects on depression. Further studies are warranted to examine supplementation with omega-3 PUFAs for specific subgroups of subjects with inflammation, severity of depression, and the dose response for both EPA and DHA supplementation.

Fig. 1

Flow chart of literature search and study selection. This figure described the route of studies inclusion. Among 204 researches from database and other studies, there are 26 trials were satisfied for the criteria of our study. MDD major depressive disorder, RCT randomized control trial

Fig. 2

Forest plot: omega-3 PUFAs vs control. There was significant effect of omega-3 PUFAs therapy for depression compared to placebo using random effect model. There was also significant evidence of heterogeneity between trials. Size of green plot proportional to weight in meta-analysis. Black lines, show confidence intervals. SD standard deviation, Std. Mean difference standardized mean difference, IV. Random Random (inverse variance heterogeneity), CI confidence interval

Fig. 3

Funnel plot of effect sizes for clinical trials included in the meta-analysis. This funnel plot depicts the standardized mean difference of trials versus their standard error. Published trials are depicted as dark circles. The dotted line bracket the 95% CI for the expect results of trials given this estimated underlying effect size