Prenatal and postnatal omega-3 supplementation for the prevention and treatment of atopic dermatitis: a systematic review of randomized controlled trials

Background Atopic dermatitis (AD) is a prevalent chronic inflammatory skin disease of childhood. Omega-3 fatty acids have been investigated for their potential role in modulating allergic inflammation; however, evidence regarding their effectiveness in preventing or treating AD remains inconsistent. Objective To systematically review and narratively synthesize randomized controlled trial evidence on prenatal and postnatal omega-3 fatty acid supplementation for the prevention and treatment of AD in infants and children. Methods PubMed and Web of Science were searched in October 2025, with an updated PubMed search in October 2026, to identify randomized controlled trials of omega-3 supplementation given during pregnancy or after birth that reported AD outcomes. Data were extracted, and risk of bias was assessed using RoB 2. Trials were grouped by clinical indication (prevention or treatment) and timing of supplementation, and a narrative synthesis was performed because of substantial heterogeneity. Results Eleven randomized controlled trials were included: nine prevention trials (six prenatal and three postnatal) and two treatment trials in children with established AD. Prenatal supplementation did not show a consistent preventive effect. Lower IgE-associated eczema was reported in two trials in high-risk families, but the effect was not always significant after adjustment and did not persist at longer follow-up; the two most recent trials found no overall effect, and one trial reported more eczema with omega-3. In one trial, the effect differed by maternal PTGS1 (COX-1) genotype. None of the three postnatal prevention trials found a significant effect. Both treatment trials reported improvement in AD severity, but they were small and short, and one used a multi-component product. Risk of bias was low in one trial, raised some concerns in seven, and was high in three. Conclusions Randomized controlled trial evidence does not support omega-3 supplementation for the prevention of AD, whether given prenatally or postnatally. Limited evidence suggests a possible benefit in children with established AD, which should be tested in larger trials. Any role of fatty acid composition or maternal genotype remains hypothesis-generating. Systematic Review Registration PROSPERO CRD420251161453.