Can vitamin D help in achieving asthma control? Vitamin D "revisited'': an updated insight.

Asthma - a prolonged respiratory disease related with hyper-responsiveness and increased inflammation of airways; affects millions peoples worldwide. Vitamin D possess anti-inflammatory and immunomodulatory activities. Its deficiency (the level less than 20 ng/mL in the serum) is found to be related to occurrence of pulmonary diseases including bacterial and viral infections and asthma. Some studies indicate that low levels of vitamin D in the serum are related to reduced lung function and increased airway inflammation as well as overall poor results in asthmatic patients. Thus, it provides positive relation between vitamin D and asthma. Increased prevalence of asthma over the past decades causes elevated interest in vitamin D supplementation that is even reported as a ,,potential therapeutic option''. Unfortunately, results of clinical trials are inconsistent and do not provide supportive information about positive role of vitamin D in asthma. Little or even no effect of supplementation of vitamin D in improvement of onset, symptoms or progression of asthma was found in comprehensive interventional studies in adults, children and pregnant woman. This review critically summarized the last years evidence of a relation between vitamin D and asthma in adults, children and pregnant women.