Epidemiological studies have shown a significantly increased risk of developing multiple sclerosis (MS) in people who are vitamin D deficient, and have correlated increased symptomatology in MS patients with lower serum levels of 25-hydroxy vitamin D. To test the tolerability and safety of high doses of vitamin D in MS patients, researchers from the University of Toronto and two hospitals in Toronto gave 12 MS patients 1,200 mg elemental calcium along with increasing doses of vitamin D for 28 weeks. The starting dose was 28,000 IU per week, which was increased to 280,000 IU per week. Serum 25-OH vitamin D levels rose dramatically, to a mean of 154 ng/mL at the end of the study. This supraphysiological level was not associated with any negative effects on liver or kidney function, or on serum or urinary calcium levels. MS disease activity was not affected; however, the mean number of gadolinium-enhancing brain lesions was significantly decreased during the study. This is a groundbreaking study, as it demonstrates that a very high vitamin D oral dosage and the resultant very high serum 25-OH vitamin D level are safe in MS patients. This may stimulate researchers to use higher supplemental therapeutic vitamin D doses in the future, which will provide more safety and efficacy data regarding supplementation with this essential nutrient.
Kimball SM, Ursell MR, O'Connor P, Vieth R. Safety of vitamin D3 in adults with multiple sclerosis. Am J Clin Nutr 2007;86:645-651.
