Asthma, allergy and respiratory infections: the vitamin D "hypothesis"

According to commentary in the January issue European Journal of Clinical Allergy and Immunology, the recent discovery that every tissue in the human body has vitamin D receptors and that vitamin D has multiple genetic effects has prompted an increased interest in this hormone. Vitamin D deficiency is widespread and on the increase. There is no consensus on the serum vitamin D levels to consider appropriate for global health, the cutoffs for its deficiency, or the doses to use for its supplementation.

Vitamin D seems to correlate closely with host reactions against various respiratory infections. Epidemiological studies have shown that low serum 25-hydroxyvitamin D levels are associated with a higher risk of upper and lower respiratory infections in children and a shortage of vitamin D may contribute to asthmatic patients’ symptoms and morbidity rates. There are studies highlighting associations between childhood asthma, fetal lung and/or immune development, and maternal vitamin D intake. An insufficiency of this vitamin also seems to be implicated in the onset of childhood atopy and food allergies.

The hypothesis is that vitamin D could have a central role in these pathological situations and that it may represent a novel preventive and/or therapeutic strategy. This review emphasizes the need for controlled, prospective studies on vitamin D supplementation to clarify what role in the prevention of and treatment for asthma and allergic conditions.

Steve - while it is always nice to see these kinds of comments in prestigious medical journals, as usual, this journal is five years too late in discovering the benefits of this "novel" therapy.