The presence of higher levels of unmetabolized folic acid (UMFA) at birth was associated with the development of food allergy in children, according to a study presented at AAAAI/WAO Joint Congress 2018.
The researchers conducted a nested case-control study involving 1,394 children from the Boston Birth Cohort. Total folate, 5-methyltetrahydrofolate (5-MTHF), and UMFA concentrations were assessed at birth and in early life using a chemiluminescent assay and liquid chromatography-tandem mass spectrometry, respectively. Common food allergens were identified based on diet, clinical history, and specific-IgE (sIgE) in early life. [AAAAI/WAO 2018, abstract 275]
Seventy-eight children (5.6 percent) were diagnosed with food allergy, whereas 507 children (36 percent) had food sensitization (sIgE ≥0.45 ku/L).
Compared with children without food allergy, those with food allergy had a higher UMFA level (mean, 1.7 vs 1.3 nmol/L; p=0.001) and a lower total folate level at birth (mean, 30.2 vs 35.3 nmol/L; p=0.02), with a higher UMFA level at birth significantly associated with the development of food allergy (odds ratio, 9.4, 95 percent confidence interval, 1.9–47.2; p=0.007; test for trend p=0.001).
Total folate, 5-MTHF, or UMFA levels at early life were not associated with the occurrence of food allergy.
“The association between UMFA and food allergy only seems to be present at birth,” said study lead author Dr Emily McGowan from the Division of Asthma, Allergy & Immunology at the University of Virginia School of Medicine in Charlottesville, Virginia, US. Potential reasons for the association include increased exposure to synthetic folic acid in utero or underlying genetic differences, she said.
“Folate, or vitamin B9, is available in both natural and synthetic forms. Folic acid is the synthetic form of folate and is often recommended to pregnant women … When folic acid is consumed in higher quantities, some of this folic acid is not metabolized and circulates in the blood as unmetabolized folic acid,” McGowan added.
“More research is needed to conclude whether mothers should consider consuming different sources of folate like leafy green vegetables, citrus fruits, beans, or lentils instead of synthetic forms of folate,” said study co-author Dr Corinne Keet from the Johns Hopkins Hospital, Baltimore, Maryland, US.