Well, it depends. I understand many beers use some fish byproduct in their production. I wouldn’t flinch about that though.
Main thing for me is that the new craft beer varieties are so heavy in body - which makes for soaring gluten content. I can rely on crap beer though - Corona, Negra Modelo, Carlsberg, and some other cheapies use rice or corn or some shit other than wheat. Oh, and Glutiny by New Belgium is not too shabby!
I’ve found that I can tolerate goat-based dairy, but not the cow based stuff. If I do, I limit to very aged cheese like parm, gouda, gorgonzola, blue, etc. Aging breaks down the bad stuff.