Vitamin D, infections and immune-mediated diseases

Vitamin D has been an exciting fi eld of research in recent years, with more than 1400 publications published on the subject in 2008. The lay press has published articles, the internet is full of information and pharmacies have prominent displays of vitamin D supplements. Historically, vitamin D has been thought only to have an effect on calcium metabolism and bone. Vitamin D defi ciency was thought only to cause rickets or osteomalacia. Recent work has found that vitamin D affects many other cells and tissues. Basic science, epidemiological, case–control and cohort studies have been conducted that show an effect of vitamin D on infections and autoimmune diseases such as multiple sclerosis, infl ammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus and Type 1 diabetes. Further research is needed in each of these areas to elucidate the mechanism vitamin D uses to affect the immune system and to develop prevention and/or treatment guidelines.