Allergic disease in infants up to 2 years of age in relation to plasma omega-3 fatty acids and maternal fish oil supplementation in pregnancy and lactation.

We have previously reported a protective effect of maternal omega-3 long-chain polyunsaturated fatty acids (omega-3 LCPUFA) supplementation in pregnancy and lactation on IgE-associated eczema and food allergy in the infant during the first year of life. Here we investigate whether the effects of the LCPUFA supplementation on IgE-associated diseases last up to 2 yr of age and assess the relationship between plasma proportions of omega-3 PUFAs and the frequency and severity of infant allergic disease. 145 pregnant women, at risk of having an allergic infant, were randomized to daily supplementation with 1.6 g eicosapentaenoic acid (EPA) and 1.1 g docosahexaenoic acid (DHA) or placebo starting in the 25th gestational week and continuing through 3.5 months of breastfeeding. Clinical examinations, skin prick tests and analysis of maternal and infant plasma phospholipid fatty acids and infant specific IgE were performed. No difference in the prevalence of allergic symptoms was found between the intervention groups. The cumulative incidence of IgE-associated disease was lower in the omega-3-supplemented group (6/54, 13%) compared with the placebo group (19/62, 30%, p = 0.01). Higher maternal and infant proportions of DHA and EPA were associated with lower prevalence of IgE associated disease (p = 0.01-0.05) in a dose-dependent manner. Higher maternal and infant proportions of DHA and EPA were found if the infants presented none, when compared with multiple allergic symptoms, (p < 0.05) regardless of sensitization. In summary, the omega-3 supplementation offered no obvious preventive effect on the prevalence of clinical symptoms of allergic disease, but the decrease in cumulative incidence of IgE-associated disease seen during the first year still remained until 2 yr of age. Furthermore, high proportions of DHA and EPA in maternal and infant plasma phospholipids were associated with less IgE-associated disease and a reduced severity of the allergic phenotype.