People with MS are often advised to take high doses of vitamin D, but there’s been very little research to assess what effect this might have. Two recent clinical trials (CHOLINE and SOLAR) investigated the effect of vitamin D supplements in people with relapsing remitting MS already taking a disease modifying drug.
CHOLINE: 129 participants already taking Rebif (beta interferon 1a) and with low blood levels of vitamin D were recruited at 27 MS clinics in France. They were randomly assigned to take either 100,000 IU vitamin D3 (equivalent to about 7,000 IU/day) or placebo, once a fortnight for just under two years. The main measure of the study was a change in the number of relapses.
SOLAR: 229 participants already taking Rebif were recruited from 40 MS clinics in Europe and assigned to take either 14,000 IU vitamin D or placebo each day for just under one year. The main measure was the proportion of people at week 48 with no evidence of disease activity (NEDA), a measure which combines no relapses, no increase in disability and no new lesions seen on MRI scans.
Neither study was able to show a clear benefit from taking vitamin D as an add-on to disease modifying drugs but did show some improvements in MRI measures, indicating there may be some improvements in MS activity.
The researchers from these two studies teamed up to consider their results. They conclude that the effect of vitamin D supplementation is uncertain and less pronounced than might be expected from correcting low blood levels of vitamin D observed during relapses and MS progression. There could be a number of reasons for this discrepancy; for example, low vitamin D levels and more active MS are in fact unrelated and independently caused by a third, unknown factor.
The researchers conclude that doses of 1000-2000 IU/day would be sufficient to ensure bone health, an important role of vitamin D. They also suggest that a dose of 4000 IU/day would be reasonable advice for people with MS in northern parts of Europe to maintain ideal blood levels of vitamin D.
From the MS Trust.