Vitamins and minerals
Vitamin D insufficiency and deficiency have been associated with IgE sensitization157 and FA in some studies158but not others.159There is little evidence from interventional studies of vitamin D supplementation for primary allergy prevention160-163 as reviewed by Yepes-Nunez, et al.164 The lack of evidence about the role of vitamin D in FA risk is in part related to the multiple factors influencing vitamin D levels that need to be accounted for when designing studies. These factors include sun exposure, country and latitude of residence, migratory status, skin colour, ethnicity, age, diet, vitamin D supplementation (timing, formulation and dose), genetic polymorphisms affecting metabolism, epigenetic changes contributing to vitamin D levels, vitamin D binding protein, interaction with disease-associated genetic polymorphisms (e.g., ORMDL3), definition of vitamin D insufficiency/deficiency, and time-points to assess levels (longitudinal versus cross-sectional)165.
One systematic review indicated that intake of beta-carotene, vitamin E, zinc, calcium, magnesium, and copper during pregnancy might be protective of offspring AD146. This review also summarized a small number of papers indicating that copper and vitamin C intake during pregnancy may reduce the risk of offspring FA. In contrast, vitamin D intake was associated with an increased risk of offspring FA. The amount of vitamins and minerals taken in these studies did not align with healthy eating guidance, and the results should be interpreted with caution146.
Results from RCTs have been summarized in several guideline papers and systematic reviews, with or without meta-analysis, to guide families. Results from these meta-analyses largely support current recommendations from the American Academy of Pediatrics (AAP),166EAACI,17 and the consensus statement from the 3 North American allergy societies.16 All refrain from making recommendations on omega-3 fatty acids, vitamins, minerals, or pre-/pro-/syn-biotics for allergy prevention.