The incidence of gluten intolerance has changed from 1:3000 to 1:150 to now 1:50.

Over the years reading and posting on gluten boards, I have seen many people with neuro issues improve on the diet.
There is a very interesting study from 1999 showing that NSAIDs, that block Cox-2 enzymes in the gut contribute to developing gluten intolerance. Since NSAIDs went OTC , the incidence of gluten intolerance has increased tremendously.
The Cox-2 inflammatory enzymes, block the absorption of things from the GI tract that are in food. It is a very interesting connection IMO. So if this turns out to be a big factor, many without the genetics, may have acquired a gluten intolerance. The data keeps coming in on this subject...so I think it should be considered, carefully.

Another intolerance is FRUCTOSE! I just discovered that this is what was bothering me, instead of gluten. (this past summer).

The GI gas, was so bad, finally, and no tests were showing disease (no gall bladder or other GI lesions) I just stopped eating all together! When I had a Gatorade a couple of days later I got so sick... again! This was triggered by a Hershey's product high in Sorbitol. While I was angry at the time, at least now I know now what fructose does to me!

Jellies, many foods, have high fructose corn syrup. Many fruits are very high in fructose. Apples and pears are at the top of the list. I have found this winter I can have ONE orange daily and stay normal. ButI do not drink any juices anymore. I can only have a bit of chocolate now and then... it has sucrose in it. I use no sugar in my tea. Honey is a nightmare for me. I used to put it in my tea...and suffer a couple of hours later. I don't miss the sugar anymore, and take Vit C separately.
I did some research... fructose intolerance can be as high as 1:3 !