Okereke OI, Vyas CM, Mischoulon D, et al. - Researchers examined if long-term supplementation with marine omega-3 fatty acids (omega-3) could aid in preventing depression in the general adult population.

• In the VITAL-DEP (Vitamin D and Omega-3 Trial-Depression Endpoint Prevention) ancillary study to VITAL (a randomized trial of cardiovascular disease and cancer prevention among 25 871 US adults), a total of 18,353 adults were included.

• Participants were randomized to receive vitamin D3 (2000 IU/d), marine omega-3 fatty acids (1 g/d of fish oil, including 465 mg of eicosapentaenoic acid and 375 mg of docosahexaenoic acid) or placebo.

• Mixed findings of a statistically significant rise in risk of depression or clinically relevant depressive symptoms (hazard ratio, 1.13) were observed in correlation with providing daily omega-3 supplementation vs placebo but there was no significant difference in change in 8-item Patient Health Questionnaire depression scale mood scores (0.03 points, comparing omega-3 with placebo), over a 5-year treatment period.

• Overall findings do not yield evidence supporting the use of omega-3 fatty acid supplements to prevent depression in adults.