McGowan EC, Hong X, Selhub J, et al. - Researchers undertook this nested case control analysis in the Boston Birth Cohort (BBC) in order to evaluate the development of food sensitization (FS) and food allergy (FA) in relation to total folate, 5-methyltetrahydrofolate, and unmetabolized folic acid (UMFA) levels at birth and in early childhood. This study included overall 1,394 children: 507 children with FS and 78 with FA. Depending on food-specific IgE (sIgE) levels, diet, and clinical history, they categorized children as FS (sIgE ≥ 0.35 kU/L), FA, or non-FS/FA (controls). Findings revealed the link of higher levels of UMFA at birth with the development of FA among children in the BBC, which may be attributable to increased exposure to synthetic folic acid in utero or underlying genetic variations in synthetic folic acid metabolism.