Maternal dietary antioxidant intake in pregnancy and childhood respiratory and atopic outcomes: birth cohort study

Evidence for a possible protective effect of maternal dietary antioxidant intake during pregnancy on childhood asthma and other atopic outcomes is conflicting, and associations with childhood lung function have been little studied. In the Avon Longitudinal Study of Parents and Children, we analysed associations between maternal intake of fruits, vegetables, vitamins C and E, carotene, zinc, and selenium in pregnancy and current doctor-diagnosed asthma, atopy and lung function in 8915 children at age 7–9 years. Potential modification of associations by maternal smoking and common maternal antioxidant gene polymorphisms was explored to strengthen causal inference. After controlling for confounders, positive associations were observed between maternal intake of zinc and childhood forced expiratory volume in 1 s and forced vital capacity (difference in age-, height- and sex-adjusted sd units per quartile increase in maternal dietary zinc intake β 0.05 (95% CI 0.01–0.08); p(trend)=0.01 and 0.05 (95% CI 0.02–0.09); p(trend)=0.005, respectively). Weak evidence was found for an interaction between maternal zinc intake and maternal glutathione S-transferase GSTM1 genotype on childhood forced vital capacity (p(interaction)=0.05); association among the GSTM1 null group β 0.11 (95% CI 0.05–0.17); p(trend)=0.001. Our results suggest that a higher maternal intake of zinc during pregnancy may be associated with better lung function in the offspring.