Fat-soluble vitamins as disease modulators in multiple sclerosis

Fat-soluble vitamins (A, D, E and K) have properties that could be relevant as modulators of disease activity in multiple sclerosis (MS).

We performed a systematic search on PubMed and Medline up to May 2012, using the search strings 'vitamin A', 'retinol', 'retinal', 'carotenoids', 'vitamin D', 'vitamin E', 'alpha-tocopherol', 'vitamin K' in conjunction with 'multiple sclerosis', 'animal model' and 'experimental autoimmune encephalitis (EAE)'. In addition, the reference lists of the publications identified were examined for further citations of relevance.

There is comprehensive evidence from epidemiological, observational, and experimental studies that vitamin D may be beneficial in MS. Results from small-scale clinical studies are inconclusive, and large-scale, adequately powered, randomized, controlled trials are still lacking. For vitamin D, Oxford Centre for Evidence-Based Medicine level 2c evidence exists for a positive therapeutic effect. Evidence from animal models indicates that all the examined fat-soluble vitamins could have potential as modulators of disease activity in MS. For vitamin A and E, level 4 and 5 evidence exists for a modulatory effect in MS; for vitamin K, too few studies have been conducted to indicate an effect in humans.

Vitamin D is a promising candidate as modulator of disease activity in MS, and controlled studies are currently being conducted. All the fat-soluble vitamins have, however, been demonstrated to be effective in different animal models for the disease, and vitamin A and E have biological properties that could be relevant for MS pathogenesis. Thus, vitamin A and E seem to be promising candidates for future case-control and cohort studies.