I do react to gluten and grains and have for many years. I remember the Doc who nearly killed me at my type 1 diagnosis telling me to use Metamucil for IBS. In 7 minutes I had severe diarrhea. I wish someone had told me to eliminate them years ago because I’m sure now it did affect me getting type 1 by affecting my bowels etc. and as well as contributing to a host of other issues. As far as the thyroid disease goes I don’t believe it would prevent Graves’ disease if you’re going to get it but it may help your treatment and symptoms to avoid it for Hashimotos. I think we’re talking about long term effects here in other words if you ate gluten your whole life and then stopped it for two years it may not be enough to reverse any damage it may have done.
Another thing I react to are tomatoes as well as vitamin c in any actual vitamin form. Lactose as well to a lesser degree maybe. When I eliminated gluten for cross contamination and all grains I stabilized my Bg crashing every time I ate and gained back 20 lbs or so I had lost last spring when I was hospitalized and had a whole host of digestive issues going in. It’s not perfect now but it’s a lot better. I also found being too thin makes my Bg management nearly impossible.
I don’t trust testing on any of these issues especially allergy testing because I have multiple allergies to dust and other things yet I’ve never tested positive for them.