I haven't read up much on the Faroe Island 'outbreak' but I know that the Scots have one of the (if not the) highest MS rates in the world and the theory is that they have the genetic susceptibility. I'm not big on the food theory - although diets may have some effect e.g. Vit D consumption. It strikes me that soldiers going to a fairlyy isolated island are going to be bringing with them infections of some sort of another and passing these to the locals. Attached is an old favourite of mine. Dr Ann Cross - a neurologist specialising in MS. The key point is:
When three of her classmates during medical training developed the debilitating and then-untreatable neurological disease multiple sclerosis (MS)
Given that the chance of getting MS is say, 1 in 800, I cannot believe that Dr Cross had 2,400 classmates. Or that the three suddenly started eating different food.
One of the theories behind fatigue is that it is the body constantly trying to fight off the infection in the CNS.
I also posted after my attendance at the EBV / MS seminar a case of an 'outbreak' of MS at a school in Denmark (following a bout of Mono / Glandular Fever).
There is also my own case - where two of three colleagues working in the same roon were dx with MS within 12 months of each other (and no Bob, I didn't kiss him).
There is also the case of immigrants to Canada (one from Iran who posts on this site) who have been dx with MS after coming from so-called low-risk countries. I don't know what Canadians eat (Moose heads or whatever), but I cannot believe that diet can cause outbreaks.
Food may well help (giving some protection / damepning down the inflammation) but I still think that an infectious agent combined with genetic susceptibility, is the root of the problem.