Great question. Gluten proteins tend to have a structure that is
- difficult to digest
- recognized by our bodies as an antigen (invader)
Not all proteins share this similarity with gluten. Prolamines in particular are difficult to digest and were originally identified as being soluble in alcohol. Recent study has shown that the glutelin fraction of gluten proteins causes reactions in many with gluten intolerance.
The science on all of this is still in its infancy. So we are learning more and more with new research.
Teff does have gluten. I do not recommend it.
All the best,