But, new studies, having their roots in an outbreak of flu in a hospital for insane criminals that skipped a ward where inmates were on Vitamin D supplements, show that in fact Vitamin D has significant immune system benefits (Science News subscription may be required for link).
On the basis of more than 100 articles that he collected, [John J.]Cannell and seven other researchers now propose that vitamin D deficiency may underlie a vulnerability to infections by the microbes that cathelicidin targets. These include bacteria, viruses, and fungi, the group notes in a report available online for the December Epidemiology and Infection.
Cathelicidin is an anti-microbial agent produced by the human body as part of its immune system.