Increased intake of oily fish in pregnancy: effects on neonatal immune responses and on clinical outcomes in infants at 6 mo.

BACKGROUND Long-chain n-3 PUFAs found in oily fish may have a role in lowering the risk of allergic disease. OBJECTIVE The objective was to assess whether an increased intake of oily fish in pregnancy modifies neonatal immune responses and early markers of atopy. DESIGN Women (n = 123) were randomly assigned to continue their habitual diet, which was low in oily fish, or to consume 2 portions of salmon per week (providing 3.45 g EPA plus DHA) from 20 wk gestation until delivery. In umbilical cord blood samples (n = 101), we measured n-3 fatty acids, IgE concentrations, and immunologic responses. Infants were clinically evaluated at age 6 mo (n = 86). RESULTS Cord blood mononuclear cell (CBMC) production of interleukin (IL)-2, IL-4, IL-5, IL-10, and tumor necrosis factor-α in response to phytohemagglutinin (PHA) and of IL-2 in response to Dermatophagoides pteronyssinus allergen 1 (Derp1) was lower in the salmon group (all P ≤ 0.03). In the subgroup of CBMCs in which an allergic phenotype was confirmed in the mother or father, IL-10 production in response to Toll-like receptor 2, 3, and 4 agonists, ovalbumin, salmon parvalbumin, or Derp1 and prostaglandin E(2) production in response to lipopolysaccharide or PHA was lower in the salmon group (all P ≤ 0.045). Total IgE at birth and total IgE, incidence and severity of atopic dermatitis, and skin-prick-test positivity at 6 mo of age were not different between the 2 groups. CONCLUSION Oily fish intervention in pregnancy modifies neonatal immune responses but may not affect markers of infant atopy assessed at 6 mo of age. This trial is registered at clinicaltrials.gov as NCT00801502.