New research from scientists at John Hopkins University has revealed that taking a high dose of vitamin D3 is not only safe for those suffering from multiple sclerosis (MS), but may actually regulate their hyperactive immune response.

"These results are exciting, as vitamin D has the potential to be an inexpensive, safe and convenient treatment for people with MS," Peter Calabresi, one of the study's authors, said in a press release. "More research is needed to confirm these findings with larger groups of people and to help us understand the mechanisms for these effects, but the results are promising."

It has long been known that low vitamin D levels are correlated to an increased risk of developing MS, and those suffering from the disease with low levels of vitamin D typically have greater disability and increased disease activity.

The study examined 40 people with relapsing-remitting MS, and each received either 10,400 international units or 900 international units of vitamin D3 supplements daily for a six-month period of time; patients with extreme vitamin D deficiency were not included in the study in order to avoid skewing the results. Blood tests began at the onset of the study and again at the three and six-month marks of the study and measured levels of vitamin D levels in the blood and the response of the immune system's T cells, which play a huge role in MS.

The results showed that subjects taking the high dose of vitamin D had a reduction in the percentage of inflammatory T cells that are connected to MS severity, in particular IL-17+CD4+ and CD161+CD4+ cells. Additionally, with every increase in vitamin D over base line levels greater than 18 ng/ml, each five ng/ml increase led to a subsequent one percent decrease in the percentage of IL-17+CD4+ T cells in the bloodstream. Conversely, subjects that took low dose vitamin D supplements did not experience any noticeable changes in their T cell subsets.

"We hope that these changes in inflammatory T cell responses translate to a reduced severity of disease," Calabresi said. "Other clinical trials are underway to determine if that is the case."

The findings were published in the Dec. 30 online issue of Neurology.