Folic Acid Levels At Birth Associated with Onset of Childhood Food Allergies

While prior studies have suggested an association between folate or folic acid exposure and the onset of food allergies, data have been inconsistent. Researchers from the University of Virginia (Charlottesville, Virginia), Tufts University (Boston, Massachusetts), and John Hopkins University (Baltimore, Maryland) recently sought to determine with greater confidence whether exposure to these molecules is associated with the development of allergic disease.

Folate is a naturally-occurring B vitamin commonly found in vegetables including asparagus, spinach, and garbanzo beans. Folic acid is a man-made fully oxidized monoglutamate form of the vitamin incorporated in dietary supplements and processed foods.

The researchers performed a nested case control study through the Boston Birth Cohort (BBC), examining the concentrations of total folate, 5-methyltetrahydrofolate (5-MTHF), and unmetabolized folic acid (UMFA) participants at birth and in early childhood. The incidence of food sensitization (FS) or food allergy (FA) was determined based on the levels of food-specific IgE (sIgE), clinical history, and diet.

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Of 1394 study participants, 507 were identified as having FS and 78 FA. Children that developed were found to have a lower average total folate concentration at birth (P=0.02) but a higher concentration of the synthetic folic acid derivative UMFA (P=0.001). Concentrations of 5-MTHF and UMFA in early childhood were not associated with FS or FA onset.

The research team concluded that, among children in the Boston Birth Cohort, increased folic acid levels at birth were associated with the development of food allergies. The team suggested that this could be attributed to in utero exposure to synthetic folic acid or genetic differences in the metabolism of synthetic folic acid.

McGowan EC, Hong X, Selhub J, et al. (2020) Association Between Folate Metabolites and the Development of Food Allergy in Children. The Journal of Allergy and Clinical Immunology: In Practice, 8(1), 132-140.e5.