Omega-3 fatty acid supplementation and cognitive function: are smaller dosages more beneficial?

As longevity increases, so does the global prevalence of cognitive dysfunction. Numerous lifestyle and/or dietary interventions such as omega-3 fatty acids have been suggested to improve memory. Therefore, this study examined the consistency and strength of the impact of supplementation of omega-3 fatty acids on overall cognitive function using systematic reviews and meta-analytic methods. Of 905 studies retrieved from all searches, 12 randomized controlled trials were included in the meta-analysis. There were differences between studies reporting outcomes for single memory function parameters. Subgroup analysis of doses used (low versus high) indicated that subjects receiving low (<1.73 g/day) doses of omega-3 fatty acids had a significant reduction in cognitive decline rate (-0.07, 95% confidence interval -0.01, -0.02) but there was no evidence for beneficial effects at higher doses (+0.04, 95% confidence interval -0.06, +0.14) compared with the placebo group. This study suggests that omega-3 fatty acids may be beneficial in preventing memory decline at lower doses.