Vitamin D and asthma

Abstract

The mechanisms for the aetiology and pathobiology of allergy and asthma are currently matters of hot debate in the scientific world. Each week it seems that a new theory for their origins is proposed, new evidence for causation is discovered and new suggestions for prevention are extrapolated. It is highly likely that allergy occurs in the human host when tolerance to environmental allergens fails to occur. This process is most obvious in early infancy. The link between allergy and asthma is another leap of faith. It is most likely that the mechanisms that develop to predispose a human subject to asthma are only partly linked to allergy. Other factors and processes must be occurring at least synergistically to produce the asthma phenotype. Finally, even when asthma occurs its phenotypic expression has a myriad of syndromes. One of the topical phenomena in the overlay of all of these conditions is vitamin D deficiency and insufficiency. Again probably, given the evidence, vitamin D is linked to allergy and asthma disease states. However, before we rush to attribute these common problems to a nutritional defect we need significantly more information that vitamin D replacement will aid in therapy or prevention. The risk of not doing so is that the ‘cure’ for asthma is ascribed to a ‘natural product’ and our patients are led gullibly off in the wrong direction.