Genetically predicted effects of DHA and EPA on cognitive performance: evidence from two-sample Mendelian randomization

Abstract

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are biochemically distinct long-chain omega-3 polyunsaturated fatty acids with different brain distributions and metabolic roles. Despite their biological specificity, most intervention trials administer combined supplements, precluding fatty acid-specific causal conclusions. Whether individual circulating DHA and EPA levels exert independent effects on cognitive function remains unresolved. Aim of the study: To estimate and formally compare the genetically predicted causal effects of circulating DHA and EPA on reaction time and general cognitive performance using a twosample Mendelian randomization (MR) framework, with explicit assessment of FADS-cluster pleiotropy.