Recent studies suggest the importance of Vitamin D3 in immunity, and indeed, vitamin D3 deficiency has been linked to multiple sclerosis, rheumatoid arthritis, hypertension, heart disease, depression, diabetes, chronic pain, osteoporosis and many other illnesses:
Vitamin D3 has also been shown to play an important role in host defense against pathogens by promoting the production of the human antimicrobial peptides, cathelicidins (LL-37). These cathelicidins have been found to have broad spectrum antimicrobial activity, showing activity against a variety of pathogens.
While cathelicidins (LL-37) have been shown to have little or no direct effect against C. pnuemoniae, Vitamin D3 has been shown to disrupt the mechanism that the intracellular forms of C. pneumoniae use to prevent normal celluar apoptosis, and it is believed that Vitamin D3 is active against the intracellular forms of C. pneumoniae through this mechanism. The resulting die-off effects from Vitamin D3 can be quite large, and symptoms of secondary pophryia can also be dramatically increased. Vitamin D3 levels should therefore be increased very slowly when treating a C. pneumoniae infection!