Taking a high dose of vitamin D3 is safe for individuals with multiple sclerosis (MS) and may help regulate the body's hyperactive immune response, according to a pilot study published by Johns Hopkins physicians in Neurology (2015 Dec 30. [Epub ahead of print]). 
Low blood levels of vitamin D are tied to an increased risk for developing MS. Individuals who have MS and low levels of vitamin D are more likely to have greater disability and more disease activity, the researchers