Want to lower your risk of MS symptoms and relapse? Take vitamin D. A lot of it. That's basically been the message to the MS community for years. So we stocked up on our supplements and took 'em daily. But now recent research suggests that this may not be true. Two studies concluded that high doses of vitamin D did not significantly reduce MS disease activity. But before you toss out your vitamin D bottles, let's dig a little deeper into the details.