A study published in JAMA says that white people with the highest blood levels of vitamin D are less likely to develop multiple sclerosis than people with low levels. The study looked at blood samples from 7 million members of the US military. Here's a link to a short piece in the WaPo.
I've been taking a daily vitamin D supplement for maybe a year, in part because I know I don't drink enough milk to get my RDA that way, but also because of some vague half-baked notion that it might help with MS. I know there's no evidence that it could work that way, i.e., that someone who already has MS could be helped by getting more vitamin D. Perhaps this reflects a little sparkle of optimism, some kernel of hope, from a place deep in the brain that is unburdened by logic.
It's easy to let the logical parts of the brain shout down that little sparkle. It's easy to sigh disapprovingly at bee venom, amalgam replacement, laetrile, and any other "therapy" for which there is no proof of effectiveness. It's really, really hard, though, to let yourself believe that things will get better, or even that they might get better.