Blairzo:

We don't generally use the name "porridge" in the US, but I believe that is a wheat based hot cereal? Turning to a diet of mostly wheat may not be the best thing for you.

As for supplements, magnesium is one that can often help with twitching and cramping type conditions, but don't use the magnesium oxide form - that isn't absorbed very well. I use magnesium citrate, and there are several other forms as well.

Instead of your porridge, maybe you could try oatmeal. It's not quite as big of a carbohydrate hit, moderates your digestive function (eases constipation but also slows diarrhea), and contains quite a bit of magnesium which is also helpful.

I have been eating oatmeal most mornings for over a year now, and while it gets a bit boring, it seems to help a bit with my SFN, but I also have IBS and it helps a lot with that.