The Role of Polyunsaturated Fatty Acids (PUFAs) in the Primary Prevention of Allergic Diseases in Children: A Position Paper of the SIAIP Primary and Secondary Prevention of Allergic Diseases and Nutraceuticals Committees

Background: Type 2 inflammatory diseases are among the most common chronic inflammatory conditions in childhood and represent a growing global health burden. Increasing evidence suggests that early-life nutritional exposures may influence immune programming and allergic disease development. This Position Paper aims to summarize the current evidence regarding the immunomodulatory role of polyunsaturated fatty acids (PUFAs), particularly omega-3 long-chain fatty acids, in the prevention of allergic diseases during early life. Methods: A scoping literature review and consensus process were conducted to map biological mechanisms and clinical evidence linking omega-3 PUFAs with allergic disease prevention. This document analyzed experimental, observational, and randomized controlled studies evaluating maternal prenatal/lactational omega-3 exposure. The clinical evidence was qualitatively appraised using study-design-specific Joanna Briggs Institute (JBI) Critical Appraisal Tools. Particular attention was given to immune modulation, inflammatory pathways, epithelial barrier function, gut microbiota interactions, and the ferroptosis–immune–metabolic axis. Results: Omega-3 PUFAs, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), exert immunomodulatory and anti-inflammatory effects through multiple mechanisms, including specialized pro-resolving mediator production, regulation of T-helper cell responses, cytokine modulation, maintenance of epithelial barrier integrity, and microbiota interaction. Emerging evidence also supports their involvement in oxidative stress and ferroptosis regulation. Current clinical evidence, particularly from higher-quality prenatal randomized trials and evidence syntheses, suggests that adequate maternal omega-3 intake during pregnancy and lactation may reduce the risk of respiratory allergic outcomes, especially wheezing and asthma, in selected offspring. Conclusions: Adequate omega-3 PUFA intake, such as 2 g/die, during critical windows of immune maturation may represent a valuable strategy for the primary prevention of allergic diseases. Current evidence most strongly supports supplementation during pregnancy and lactation, particularly in populations with low dietary omega-3 intake or increased allergic risk. Omega-3 supplementation should be considered within a broader multifactorial preventive approach aimed at promoting immune tolerance and reducing the future burden of allergic diseases.