Berti,
The Times ran a big piece on Vitamin D recently, hailing it as the new wonderdrug( as it has been called before, in other lifestyle pieces), and Vitamin D supplements are the essential requirement for all sorts of diseases, from 'flu prevention to stopping skin cancer in its tracks, and curing diabetes and MS along the way.
IMO basically a typically overblown piece of lifestyle media reporting with respect to the efficacy of Vitamin D, sadly lacking any scientific rigour, but follow the link and make your own mind up ;)
http://www.timesonline.co.uk/tol/life_and_styl e/health/article6373802.ece