Vitamin D and allergies

An increasing amount of evidence has established that the biologically active form of vitamin D, 1,25-dihydroxy vitamin D3, possesses immunoregulatory properties. Vitamin D exerts its effects through binding to the nuclear vitamin D receptor (VDR), which is expressed by cells of the immune system. Most of the immunological effects mediated by vitamin D-VDR are regulatory, inhibiting adaptive immune responses. It has become apparent that the incidence of vitamin D insufficiency is surprisingly high in the general population. A link between low vitamin D serum levels and the increased prevalence of allergic diseases has been proposed. This possible connection has been investigated in numerous studies on associations between vitamin D serum concentrations and different allergic conditions, as well as studies on the effect of vitamin D supplementation. Although there is some evidence for a protective role of vitamin D in asthma, no consensus on the role of vitamin D in allergic disease has yet been reached. Still, treatment strategies involving vitamin D supplementation to risk groups, combinatorial corticosteroid and vitamin D treatment in asthma and vitamin D as an immunomodulator in allergen specific immunotherapy show promise for the future.