Published Online: January 25, 2015
Asthma is a condition that can lead to chronic respiratory symptoms and loss of lung function, caused by inflammation of the airways. Although most patients can control their disease with relative low doses of medication, some patients continue to experience symptoms despite extensive treatment. For these patients there is an urgent need for new treatments to suppress inflammation and thus result in better asthma control. Now, in a study recently published in The Journal of Allergy and Clinical Immunology (JACI), de Groot and colleagues present the results of a study on the effect of vitamin D on airway inflammation in asthma.
The authors of this study treated 44 non-allergic asthma patients over a period of two months. Patients were divided into two groups and, in addition to their own asthma medication, were given either a single high dose of vitamin D, which was added to a serving of yogurt, or a placebo. Notably, vitamin D levels stay elevated for several months after administration, due to storage in fat tissue. To measure the possible benefits of this treatment, all patients were examined before and at the end of the treatment regime, and the type and extent of inflammation in their airways was determined by analyzing coughed up sputum. Additionally, the authors studied effects on asthma symptoms and lung function.
When all patients were studied independent of the type of airway inflammation, vitamin D did not seem to have an effect. However, in the subgroup of patients with eosinophilic inflammation, vitamin D appeared to be effective. Patients with high levels of eosinophilic inflammatory cells in sputum (≥26.2%, based on median of total group) at baseline who received vitamin D showed an impressive decrease of these eosinophilic cells as compared to patients receiving placebo. Moreover, after two months, slightly better asthma control was observed in patients receiving vitamin D. Side effects were the same in frequency and severity in both groups.
This study shows that vitamin D might be a promising new agent to reduce airway inflammation in certain types of uncontrolled asthma. This suggests that vitamin D, with its favorable safety profile and low costs, could be a new treatment option to reduce medication needs and improve asthma control. However, this study examined relatively few patients, and studies looking at a larger group of patients are needed. It would also be interesting to explore long term effects of treatment with vitamin D.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.