Many studies and observations have shown there to be a definite link between Vitamin D, Magnesium and Asthma. There is an increased prevalence of vitamin D and serum magnesium deficiency in people with asthma. A lower level of either or both is associated with an increased asthma severity and frequency of attacks.
Researchers have found the severe asthma attacks that require hospital admission or are reduced by giving an oral vitamin D supplement. There is also a reduced level of asthma attacks that require treatment with steroids when vitamin D supplementation is given. Vitamin D supplementation was not found to improve lung function or day to day asthma symptoms.