Marine n-3 long-chain polyunsaturated fatty acid intake in pregnancy and risk of early life infections in three Nordic cohorts: a HEDIMED consortium study - Centre for Population Health Research (POPC) - A joint centre by the University of Turku and the municipal authority of the Hospital District of Southwest Finland. The goal of Centre for Population Health Research is to promote health and well-being of society by enhancing research and development work on clinical-epidemiological population research.

J Nutr. 2026 Feb 28:101456. doi: 10.1016/j.tjnut.2026.101456. Online ahead of print.

ABSTRACT

BACKGROUND: n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) have anti-inflammatory effects that may influence immune-mediated diseases.

OBJECTIVE: We investigated whether higher maternal pregnancy intake of n-3 LCPUFA is associated with a lower infection incidence in young children.

METHODS: We used data from three Nordic cohorts: the Norwegian Mother, Father and Child Cohort study (MoBa, n=76,026), the Finnish Diabetes Prediction and Prevention study (DIPP, n=560) and the Copenhagen Prospective Studies on Asthma in Childhood 2010 cohort (COPSAC₂₀₁₀, n=680). Childhood infections up to age 36 months were assessed using questionnaires in MoBa, coxsackievirus B 1-6 (CVB1-6) neutralizing antibodies in DIPP, and pathogenic viral PCR identification from acute respiratory episodes in COPSAC₂₀₁₀. Maternal n-3 LCPUFA intake was assessed through validated food frequency questionnaires in MoBa and DIPP, while COPSAC₂₀₁₀ used a randomized trial design where pregnant women received fish oil capsules or placebo.

RESULTS: Higher n-3 LCPUFA intake was not significantly associated with lower respiratory tract infection (adjusted incidence rate ratio (aIRR) 0.99; 95% CI 0.94-1.03) but was associated with a reduced risk of upper respiratory tract infections (aIRR 0.99; 95% CI 0.98-0.99) and gastroenteritis (aIRR 0.96; 95% CI 0.95-0.98) per g/day up to age 36 months in MoBa. The DIPP study found no association between n-3 LCPUFA intake and having ≥1 CVB infection (adjusted odds ratio 1.74; 95% CI 0.64-4.72, per g/day). The COPSAC₂₀₁₀ trial found no significant effects of the intervention for pathogen specific respiratory episodes (IRR 0.86; 95% CI 0.69-1.07).

CONCLUSIONS: This study does not provide consistent evidence that higher maternal n-3 LCPUFA pregnancy intake reduces the risk of infections in early childhood.

CLINICAL TRIAL REGISTRY: NCT00798226, https://clinicaltrials.gov/study/NCT00798226.

PMID:41771441 | DOI:10.1016/j.tjnut.2026.101456