PneumoniaHow does vitamin D work?

Vitamin D prevents pneumonia by strengthening the body’s innate immune system.

For pneumonia, there appear to be two important roles of vitamin D in reducing the risk of pneumonia.

The first is reducing the cytokine storm by shifting production from T-helper 1 (Th1) to Th2 cytokines, which generate less inflammation1. The cytokine storm disrupts the lining of the lungs, making it easier for bacteria to cause pneumonia.

The second is fighting the bacterial pneumonia through induction of cathelicidin and defensins2 as reviewed in Grant and Giovannucci3.  The vitamin D-antimicrobial peptide pathway and its role in protection against infection was recently discussed by Gombart4.

Page last edited: 03 May 2011


  1. Ardizzone, S. Cassinotti, A. Trabattoni, D. Manzionna, G. Rainone, V. Bevilacqua, M. Massari, A. Manes, G. Maconi, G. Clerici, M. Bianchi Porro, G. Immunomodulatory effects of 1,25-dihydroxyvitamin D3 on TH1/TH2 cytokines in inflammatory bowel disease: an in vitro study. Int J Immunopathol Pharmacol. 2009 Jan-Mar; 22 (1): 63-71.
  2. Liu, P. T. Stenger, S. Tang, D. H. Modlin, R. L. Cutting edge: vitamin D-mediated human antimicrobial activity against Mycobacterium tuberculosis is dependent on the induction of cathelicidin. J Immunol. 2007 Aug 15; 179 (4): 2060-3.
  3. Grant, W. B. Giovannucci, E. The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918-1919 influenza pandemic in the United States. Dermato-Endocrinology. 2009; 1 (4): 215-219.
  4. Gombart, A. F. The vitamin D-antimicrobial peptide pathway and its role in protection against infection. Future Microbiol. 2009 Nov; 41151-65.