Multiple sclerosis involves degeneration of the myelin sheath, a protective layer on nerve cells. Most treatments for MS involve trying to stop the progression of the disease, but few have attempted to promote regeneration of the myelin. Scientists have recently discovered that cells within the immune system, called Regulatory T Cells (T-reg cells for short), promote the growth of new myelin within the nervous system. Therefore, it would seem beneficial (there does not appear to be any data on this yet though) to support the production of T-reg cells. While doing research on that, I found an article that suggests a role in this regard for vitamin A, vitamin D, and probiotics. The article also discussed the potential benefit of avoiding gluten. That article can be found here:
In another article about what supports T-reg cells, folic acid was mentioned, along with green tea extract:
Regulatory T cells promote myelin regeneration in the central nervous system.
Nature Neuroscience 2017 doi:10.1038/nn.4528