With oats it’s mostly contamination that’s the issue… There’s a link between gluten intolerance and avenin-intolerance too. But not all wheat-allergic people are oat-allergic.
My mum’s got pretty bad IBS so as an experiment she went onto the diet for a couple of months… Made no difference, in her case, but does in others. Definately worth giving it a crack if you think it might be of use.
The trouble is what my brother calls “stealth glutons”, since wheat gets used as a bulking agent in so much food. Like, you wouldn’t expect a 100% beef burger to be full of wheat, or a mars bar. Some recipes change around and go from GF to not GF, which is really frustrating.
Beer is, well, complicated. You can get GF beer but also, a lot of lager is almost GF- frinstance Budweiser isn’t authenticated as GF, and so there’s no guarantee that it’ll be OK, but random sampling shows it to be safe. I just switched to cider, much simpler, and after a while it stops tasting like horse piss.