Randomized controlled trial of fish oil supplementation in pregnancy on childhood allergies

BackgroundDiets high in n-3 long chain polyunsaturated fatty acids (LCPUFA) may modulate the development of IgE-mediated allergic disease and have been proposed as a possible allergy prevention strategy. The aim of this study was to determine whether n-3 LCPUFA supplementation of pregnant women reduces IgE-mediated allergic disease in their children. MethodsFollow-up of children (n=706) at hereditary risk of allergic disease in the Docosahexaenoic Acid to Optimise Mother Infant Outcome randomized controlled trial. The intervention group (n=368) was randomly allocated to receive fish oil capsules (providing 900mg of n-3 LCPUFA daily) from 21weeks' gestation until birth; the control group (n=338) received matched vegetable oil capsules without n-3 LCPUFA. The diagnosis of allergic disease was made during medical assessments at 1 and 3years of age. ResultsNo differences were seen in the overall percentage of children with IgE-mediated allergic disease in the first 3years of life between the n-3 LCPUFA and control groups (64/368 (17.3%) vs 76/338 (22.6%); adjusted relative risk 0.78; 95% CI 0.58-1.06; P=0.11). Eczema was the most common allergic disease; 13.8% of children in the n-3 LCPUFA group had eczema with sensitization compared with 19.0% in the control group (adjusted relative risk 0.75; 95% CI 0.53-1.05; P=0.10). ConclusionsOverall, n-3 LCPUFA supplementation during pregnancy did not significantly reduce IgE-associated allergic disease in the first 3years of life. Further studies should examine whether the nonsignificant reductions in IgE-associated allergies are of clinical and public health significance.