''Not a Universal Effect'': Polyunsaturated Fatty Acids and Cognition from Pregnancy to Adolescence-A Narrative Review and Nutritional Guidance for a Mediterranean Population

Polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are an important class of bioactive lipid mediators, essential for brain development from gestation through adolescence. Yet human studies evaluating the benefits of PUFAs for cognition remain inconsistent. This narrative review synthesizes studies from PubMed, Scopus, and Google Scholar examining PUFA intake, status, and supplementation in relation to cognitive and neurodevelopmental outcomes. It uses a thematic approach rather than the systematic search and screening protocol of a systematic review. This review also discusses the genetic determinants of PUFA metabolism and their association with neurodevelopmental outcomes, in addition to nutritional recommendations for Lebanon, a Mediterranean country. Animal models consistently show neuroprotective and anti-inflammatory effects of omega-3 PUFAs during critical windows of brain development. However, evidence from human studies evaluating the cognitive benefits of PUFAs remains limited and inconsistent, with more pronounced benefits in specific populations with low baseline PUFA status, learning difficulties, ADHD, or preterm birth. Genetic variation in genes involved in PUFA metabolism such as FADS1, FADS2, and ELOVL2/5 affects the capacity to synthesize long-chain PUFAs from dietary precursors, helping explain variability in response to omega-3 supplementation. Lebanon's traditional Mediterranean diet already supplies PUFAs and MUFAs; the real challenge is improving adherence to it through nutrition education and policy.