Verbal Memory Performance in Depressed Children and Adolescents: Associations with EPA but Not DHA and Depression Severity.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been described as positively associated with cognitive functioning. Current meta-analyses have identified eicosapentaenoic acid (EPA) as potentially more effective than docosahexaenoic acid (DHA). An especially vulnerable subgroup that might benefit from these beneficial effects are depressed youths. In this study, we examined associations between red blood cell (RBC) DHA and EPA levels and depression severity and verbal memory performance in a sample of 107 moderately (n = 63) and severely (n = 44) depressed youths. The findings showed that youths with high RBC EPA levels had steeper learning curves compared to those with moderate or low RBC EPA levels (Pillai's Trace = 0.195, p = 0.027, ηp2 = 0.097). No associations between RBC DHA levels or depression severity and verbal memory performance were observed. Our results further confirm previous findings indicating a more important role of EPA compared to DHA in relation to cognitive functioning. Future research should further investigate the differential role of EPA and DHA concerning cognitive functioning in depressed youths. Evidence supporting beneficial supplementation effects could potentially establish a recommendation for a natural and easily accessible intervention for cognitive improvement or remission.

Omega-3 and its domain-specific effects on cognitive test performance in youths: A meta-analysis.

Omega-3 fatty acids are vital for brain development. The aim of this meta-analysis was to broaden current knowledge of the effects of omega-3 supplementation on cognitive test performance in youths. Randomized controlled trials (RCTs) meeting selection criteria were identified through two independent literature searches on PubMed, Cochrane Library, PsycARTICLES and PsycINFO (last search June 2019). Twenty-nine out of 1126 studies assessing 4247 participants met all selection criteria. A meta-analysis using random-effects model was performed for eight different cognitive domains. This first analysis revealed no main effect of omega-3 fatty acid supplementation on domain-specific cognitive test performance in youths. Subgroup analyses identified beneficial effects of eicosapentaenoic acid (EPA)-rich but not docosahexaenoic acid (DHA)-rich formulations in the domains of long-term memory, working memory and problem solving and a tendency towards beneficial effects in clinical rather than non-clinical populations. Future research should investigate differential effects of EPA and DHA and consider their baseline levels, other nutritional components and interactions with gene variations as potential predictors of response.