What is the evidence for Vitamin D in preventing Multiple Sclerosis?

In 2004, research was conducted to see if vitamin D helped prevent multiple sclerosis. The  study indicating that women who get doses typically found in daily multivitamin supplements -- of at least 400 international units -- are 40% less likely to develop multiple sclerosis compared with those not taking over-the-counter supplements.

"We've known for some time that vitamin D can affect function of the immune system, which could explain why it seems beneficial to both of these autoimmune conditions," says Kassandra Munger, MSc, of Harvard School of Public Health, a researcher for this study. "In animal studies, vitamin D been shown to suppress the autoimmune response in rats with a disorder very similar to MS."

http://www.webmd.com/multiple-sclerosis/news/20040112/vitamin-d-may-prevent-ms

However, the Multiple Sclersois Research Centre posts this," On the other hand, taking high doses of vitamin D didn't help patients with multiple sclerosis,

 But overall, vitamin D gets pretty good press. The trouble is that hard evidence to back up the vitamin's benefits is lacking, according to Clifford Rosen, MD, of the Maine Medical Center Research Institute in Scarborough. "There's no data," Rosen told MedPage Today. "It's all weak association studies."

http://www.msrc.co.uk/index.cfm/fuseaction/show/pageid/1334