Sorry to hear about your husband’s problem. One of my best friends has GI issues as does her daughter and it is not pleasant. They’ve been looking for answers too, so I did some research and thought I’d chime in here. I’ll provide some thoughts on why it is not due to anti-pest measures in GMO food, then a bit on increasing celiac disease and then address potential causes, their tie to GMO, and finally a rather interesting twist on the future of GMO and celiac disease.
The anti-pest protein (we'll call it Bt from now on) does not make "stomachs explode" in any critter. That's a little hyperbole. Bt is natural and used in organic farming as a pesticide. In several GM crops scientists have simply added it to the plant cell-- no need to apply it-- the plant makes it on its own. Pretty cool. It's like if your body made a compound that made mosquitoes sick. They'd take a bite and leave!
When engineered into corn, corn earworms (troublesome pests) nibble on the end of an ear, they eat the Bt, then they stop feeding. It works because the Bt protein enters the gut, it is processed by enzymes in the larval insect gut to make the active Bt protein. This protein binds a specific receptor on the gut wall. The receptor interaction wth Bt is like a lock and key. The interaction is so specific that a Bt protein working against moth larvae won't work on many other insects.
When the receptor is bound these bound molecules get together and form a pore where the gut contents mix with the body cavity, which is bad news for the insect larvae. We digest the protein just like any other protein and there are no consequences in vertebrates for sure.
This is good news for us. Because the corn makes this protein farmers have to spray less. Bt corn and Bt cotton cut pesticide applications by 50-60% according to the 2010 National Academies book on GM Crops (Figs 2-3 and 2-7). That cuts farmer costs and brings fewer chemicals into our environment!
But since GMO crops have been around there's the increase in GI ailments, primarily celiac disease. What's up with that? It is absolutely just a correlation. In fact, GMO might actually SOLVE the problem.
(I know there's a lot to read here, I really got into your question, so PLEASE get to the punch line!!!)
Reilly et al., 2013 report that this problem is still relatively rare in the USA, although increasing. The countries with the greatest incidence include Sweden, Mexico and Finland, but it is low in Italy and Germany. It is primarily a disease found in those of European origin, with some incidence in Chilean and Asian populations. Rubio-Tapia et al (2009) show that diagnosis increases with age. One study in Sweden showed that infants with several early-life illnesses and exposure to wheat products had a higher incidence later in life. There is broad subscription to the idea of the “celiac iceberg” that the disease is much more prevalent than reported because most symptoms are mild (Mustalati et al., 2010).
As it is seen right now the causes appear to be multi-factorial (Bizzaro et al., 2012), in other words, there’s not one cause that can be pinned down. However, there is growing scientific consensus that it is a combination of factors including sensitivity to wheat proteins, a genetic component, and a pathogenic issue.
The literature consistently reports gluten intolerance as a strong contributing factor. Disease markers include irritation of the intestinal mucosa and production of antibodies toward transgultaminase, a protein complex arising from wheat. Van den Broeck et al (2010) show an increase in certain protein variants that may contribute to the disease in modern wheats that were not present in wild wheat, and suggest that these may be behind the problem.
Why wheat? Modern wheat is a genetic complexity, where all of the genes from three types of wild wheat occur in one genetic background. It happens naturally. Talk about a frankenfood! It is common in plants, known as "polyploidy". There are specific wheat protein types (alpha gliadin) that appear to induce T-cells, the body’s defense cells that trigger autoimmune responses. As wheat has been bred (bread!) for higher protein content, perhaps so has the prevalence of this, and other proteins. This was the conclusion of the aforementioned study.
Wait! But what about GMO! The big surprise is that commercial wheat is not “transgenic” or what we commonly refer to as GMO. So while traditional breeding may be contributing to the problem, it is 100% NOT due to GMO. Can't be. There is no commercial GMO wheat.
Sorry for the long walk to your answer.
Here’s the neat part. Could GMO’s stop celiac disease? Probably. Gil-Humanes et al., (2010) and Altenback and Allen (2011) report that they can use GM technology to remove, or substantially reduce, the problematic proteins. By turning off, or silencing, the genes using wheat's own sequences, the wheat does not produce the deleterious proteins.
How cool is that?
If you read websites critical to biotechnology they’ll tell you that wheat already is a GMO and that GMO wheat causes celiac disease. My guess is that is why you are here.
But the reality is that it is likely due to traditional breeding, the non-GMO process that brought us all of the major varieties we have today. In the future, GMO technology will likely contribute to removing the reactive proteins.
Wouldn’t that be quite a twist if GMO technology actually ended celiac disease? My guess is that it is exactly what will happen. Best wishes to your husband. Science is moving fast in this area and new therapies, and perhaps new foods, may make his life a little more comfortable going forward.