MS Australia has launched its large trial looking at various doses of vitamin D3 and their effect on preventing conversion to MS from clinically isolated syndrome (first attack of demyelination not yet diagnosed as MS).

That trial will not report until 2017. In the meantime, researchers from the Eye Research Centre at  the Isfahan University of Medical Sciences in Iran have looked at this important issue in a slightly different way.

Optic neuritis is well known to be a common first event in MS, being the first thing people with MS present with in 20% of cases, and of people who develop optic neuritis, 50% go on to be diagnosed with MS.

These researchers enrolled 30 people with an attack of optic neuritis into a randomised controlled trial, where half received vitamin D3 at a dose of 50,000IU a week, or around 7,000IU daily, and the other half received an inactive placebo.

They were seeking to determine whether a reasonable dose of vitamin D3 prevented conversion to MS, and if so, to what extent. The results are exciting!

Those receiving D3 had nearly a 70% reduction in risk of developing MS, and also had significantly fewer new brain lesions. This is one of the first studies to use adequate doses of vitamin D3, and this may explain why such a strong result was found.

Even though this study was small, it provides compelling evidence of the benefits of vitamin D3 in preventing MS.

After this study, even without the results of the Australian study, it would be prudent for doctors making a diagnosis of optic neuritis to start supplementation with vitamin D3. Many doctors would consider any first demyelinating event now warrants commencement of supplementation with D3, given its lack of side effects, and its potential health benefits over and above reduced risk of developing MS.