I have read that in theory, high doses of Vitamin C might be a bad idea as this vitamin 'boosts' the immune system. However I haven't come across any literature that proves it causes relapses in MS.
It does seem to come up frequently that Vitamin D is good to take when one feels a cold or flu coming on. Vitamin D modulates (is that the right word?) the immune system as opposed to 'boosting' it. Again, I've never seen a study on this angle specfically. I know of one study in Canada that is studying very high doses of D in MS patients to see if it reduces number of relapses and/or alleviates MS symtoms. The jury is still out I think although some study subjects swear they have improved (the ones on vit. D, not placebo).
I did recently read in Oprah's magazine, for what it's worth, that Dr. Oz says he makes sure he gets 10,000iu of Vitamin D through supplements or sun exposure, when he feels illness coming on.
Here is an essay - not a scientific finding by any means - but one that tinkled my interest over Vit D and Sunlight a couple years ago.
http://www.freerepublic.com/focus/chat/1929828/posts
This essay can be found all over the internet.
BTW I take 6000+ IU of Vitamin D daily. The PhDs that study this on a molecular level feel that at this time 10,000 IU daily is the highest they feel is safe to recommend for the general public - not necessarily the highest daily intake that IS safe.
I wonder how this works in with CCVIS....
Quix