The role of gut microbiota and vitamin D in the development of atopic dermatitis and food allergies in children

BACKGROUND: Gut microbiota and vitamin D may be instrumental in the development of atopic responses (atopic dermatitis, allergic rhinitis, allergic asthma, and food allergies) in children. Various diseases or immune pathologies, in particular atopic dermatitis and food allergies, are among manifestations of an imbalance in the composition of gut microorganisms. On top of that, vitamin D is a significant contributor both to modulating the gut microbiome composition and to diverse immune responses from innate and adaptive immunity, which affords ground for studying the relationship between these aspects in the context of the development of atopic conditions. So far, the relationship between the gut microbiota, vitamin D, and the development of these conditions in children has not been sufficiently explored. AIM: To study the relationship between the gut microbiota imbalance and immune disorders, in particular the development of food allergies and atopic dermatitis in children; to identify the relationship between bacterial signatures and vitamin D concentrations in children with atopic dermatitis and food allergies. METHODS: The 16S ribosomal ribonucleic acid gene of 150 fecal samples from children aged 3 to 12 years was sequenced. The concentration of vitamin D in the participants’ blood serum was determined using enzyme-linked immunosorbent assay. Thereafter, the relationship between certain bacterial signatures and serum 25(OH)D concentration was characterized through the use of statistical models (regression tree, correlation analysis, and linear regression). RESULTS: In all mathematical models used, vitamin D concentration turned out to be associated with bacterial families important for atopy, such as Lachnospiraceae, Ruminococcaceae, and Sutterellaceae. The results showed that dysbiosis coupled with vitamin D deficiency is typical of the atopic profile, which may indicate the influence of these conditions on the immune system imbalance toward the Th2 response and, consequently, on the development of allergic conditions. CONCLUSION: Certain bacterial patterns specific to atopy are associated with vitamin D concentration in blood serum. In consequence of the study, we concluded that the gut microbiota and vitamin D may be systematically involved in modulating immune responses. Further research is needed to attain full comprehension of the mechanisms underlying these associations and to determine the most efficient interventions for the prevention and treatment of autoimmune conditions.