Some new work has shown that mice fed a special diet are much less likely to suffer from Type 1 diabetes. It's possible that other autoimmune diseases, maybe PA, could also be prevented by adopting a similar diet.
The diet includes a type of fibre (resistant starches) that gets broken down in the large intestine to produce acetic acid (vinegar) and butyric acid (the smell of rancid butter).
There's no indication as to whether it might help to eat such a diet after one has already developed an autoimmune disease, but it's another argument in favour of feeding kids a lot of fruit and veg.