Higher maternal bread and thiamine intakes are associated with increased infant allergic disease

Background: A mother's diet during pregnancy may influence her infant's immune development. However, as potential interactions between components of our dietary intakes can make any nutritional analysis complex, here we took a multi-component dietary analysis approach. Methods: Nutritional intake data was collected from 639 pregnant women using a validated semi-quantitative food frequency questionnaire to reflect their dietary intakes during 32–36 weeks of gestation. To investigate their dietary intake pattern, we calculated Dietary Inflammatory Index scores. Maternal consumption of 12 food groups, 20 individual whole foods, and 18 specific nutrient intakes, along with any vitamin and mineral supplementation, were determined. Infant outcomes included eczema, allergen sensitization, and IgE-mediated food allergy. Regression-based analyses with covariates adjustment were applied. Results: Women with higher white bread consumption were more likely to have an infant with doctor-diagnosed eczema (adjusted relative risk [aRR] 1.16; 95% CI 1.08, 1.24; p <.001) and IgE-mediated food allergy (aRR 1.14; 95% CI 1.02, 1.28; p =.02). Higher maternal intakes of fiber-rich bread (aRR 1.14; 95% CI 1.04, 1.25; p =.01) and legumes (aRR 1.11; 95% CI 1.02, 1.21; p =.02) were also associated with infant doctor-diagnosed eczema. Higher maternal thiamine intakes were associated with increased parent-reported infant eczema (aRR 1.08; 95% CI 1.03, 1.12; p <.001). Conclusion: In Australia, where bread flour is fortified with thiamine, we identified consistent links between higher maternal thiamine-rich diets and increased risk of infant eczema and food allergy. Our results highlight a need for further investigation of potential effects of high thiamine exposures on immune development, especially in-utero.