A member here posted this years ago. I'm surprised this isn't more commonly known.
It's long. You can skip a bunch, down to the paragraph that starts "Here is the important part."
It seems casein is worse for our gut than gluten. Soy and corn are very damaging. Peanuts are legumes that are closely related to soy.
Personally I believe this and think everyone who goes gluten-free should know. I am disappointed that I spent effort going gluten-free but was still eating the other bad foods. When going gluten-free some people eat increased dairy, corn, and soy and this would explain some of the people who never heal their gut successfully.
Also rice. I posted another entry about many brands of rice having gluten added.
If you're gluten-free, you may want to avoid casein, soy, and corn
Blog entry posted by SickOfSickness, Sep 29, 2013.