Early-life folate levels are associated with incident allergic sensitization

Folate Deficiency, Atopy, and Severe Asthma Exacerbations in Puerto Rican Children

“…In contrast to findings from those cross-sectional studies (9, 10), a multivariate analysis of data from a 1-year prospective study of 144 children with persistent asthma (aged 5-17 yr) showed that serum folate was not significantly associated with symptoms or acute visits for asthma, lung function, fractional exhaled nitric oxide, number of positive skin tests to allergens, or asthmarelated hospitalizations; although folate level was significantly but nonlinearly associated with total IgE, such finding is of unclear relevance, given all other negative results. A separate study of 138 children studied between ages 2 and 8 years also reported results opposite of ours, in that a cluster of participants with high folate levels in early childhood had subsequently increased rates of allergic sensitization (28). The discrepancy between our findings and those from other studies (7, 28) may be explained by differences in sample size (and thus statistical power), age and race/ethnicity of participants, timing of folate measurement, and degree of adjustment for potential confounders.…”

Folate and Asthma

“…A recent study that assessed serum folate (at ages 2, 4, 6, and 8 yr) in 138 U.S. children found that approximately 75% of participants had relatively stable folate levels throughout the study (Cluster A). Compared with this Cluster A, the remaining participants (Cluster B) had significantly higher serum folate levels at ages 2 to 6 years but not at age 8 years (26). In this study, increased serum folate levels were significantly associated with allergic sensitization (to aeroallergens and food allergens) but not with total IgE at ages 6 and 9 years (26).…”

Pathophysiology of Food Allergy

“…Studies using data from the National Health and Nutrition Examination Survey (NHANES) have independently reported that vitamin D deficiency, folate levels, and increased obesity all may be associated with foodspecific IgE levels. [41][42][43] However, it should be noted, as has been pointed out by Keet and others,44,45 that food-specific IgE may not by itself be an appropriate proxy for the determination of clinical food allergy. Nonetheless, the concept that dietary factors may affect the immunologic milieu and subsequently affect the balance between sensitization and tolerance seems to be supported by these epidemiologic findings.…”