There seems to be no major effect on clinical course of MS, of polyunsaturated fatty acids, although there only limited trial information. This does not really surprise me. I would not expect a nutriceutical to have a major impact, because if they were so great they would have marked side-effects.........they don't.
However, that is not to say they have no effect and each nutriceutical may offer some small benefit, as there is experimental evidence to support some of the biology. However that often gets taken a bit far, so it becomes far- fetched in the stuff the media love to publish. "Blackcurrents save nerves"
Who is going to support studies to show benefit when it may only be incremental. This is especially the case when you use mixtures, as a basis for treatment. However, without that evidence base it is hard to recommend it.