There is a LOT of information and a vid, etc., in this article, so be sure to scroll all the way to the bottom if this subject is of interest to you.  I read about gluten free a lot because I don't believe it's as big an issue as people are making it seem, and it's become nothing more than a BIG FAT TOOL for the marketers.  I've seen the "gluten free" label on things that don't even remotely contain wheat or anything like wheat - it's gotten really crazy out there.

http://healthimpactnews.com/2017/is-the-gluten-intolerance-epidemic-as-bad-as-claimed-or-a-clever-marketing-tool/