I have found other items, that aren’t thought of as food, but might contain gluten and cause issues.
For example, prescription and over-the-counter drugs and supplements, aren’t usually thought of as food, but they are something you swallow. When you become gluten-intolerant, you must be a dedicated ingredient reader. Not only do you need to read ingredients on foods, you must find out the ingredients of any thing else you ingest–such as pills.
When I first cleaned all the gluten containing items out of my diet, I found that prescription medications, some of which I had taken for many years, were now making me sick. After investigating, it turns out that many fillers used in pharmaceuticals can contain gluten. My medication was not making me sick, it was the fillers.
Optimally, another manufacturer can be found that makes the needed medication. As I found, however, there may not be any other company making the needed medication. Or if there is, they all use a gluten containing filler.
When I found no one manufactured certain medications without gluten, I had to turn to a compounding pharmacist. These are special type of pharmacists who actually encapsulate medications themselves. In my case, I talked with the pharmacist about what items I am allergic to (I have more than just gluten). He uses the medication I need, but with a different filler, and puts that in a capsule for me. And, voilà, I can take my medication without stomach upset. The downside, it will cost you.