Vitamin D and respiratory infections the jury is still out

While recent research found no benefit of vitamin D supplements for URTIs in healthy people, leading experts strongly support vitamin D supplementation for the growing number of patients with deficiencies. Vitamin D is involved in both innate and adaptive immunity, and low vitamin D levels have been linked with an increased risk of several types of respiratory infections including upper respiratory tract infections (URTIs), influenza and tuberculosis, as well as other respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). For example, analysis of data from 18,883 participants in the Third National Health and Nutrition Examination Survey (NHANES III) demonstrated an inverse association between serum 25-hydroxyvitamin D (25-OHD) levels and recent URTI.