Celiac Disease Support Group
Celiac disease is an auto-immune disorder of the digestive system that occurs in genetically-predisposed individuals. It is characterised by damage or flattening to all or part of the villi lining the small intestine, which interferes with the absorption of nutrients. This damage is caused by eating anything with gluten (gliadin), a protein found in wheat, rye, and barley...
Two of my doctors said that if someone suspects gluten intolerance, s/he should take the "90-day challenge." This is when a person goes on a strict gluten-free diet for 90 days, after which time s/he should reintroduce gluten. If the problems return, or new ones show up, then that person should remain GF.
Be sure to read some of the older posts, as they can provide you with lots of good info. Gluten can hurt a person in many ways. Hope your fiance is able to find out for sure, but it wouldn't surprise me if gluten is causing his health problems. Best wishes to both of you.