I had a 3-year span where I could not eat gluten, and for 1 year of that I could not eat corn. My level of sensitivity was such that I could not eat gluten-free meals at any restaurant due to cross contamination nor drink instant coffee because the conveyors are sprayed with a corn-based anti-clumping solution.

I saw 3 different digestive specialists (I believe all gastrointestinologists, it's been a few years). Their approaches did nothing. Then I searched for digestive disease research centers, went to one, and was "cured" after two visits. The doctor said that my situation is becoming more prevalant, and that the issue is typically one or more of the following: A hostile bacteria in the digestive tract, overgrowth of one or more bacteria in the digestive tract, or a parasite.

A round of the following two drugs fixed me within a few days: Alinia and Neomycin. I was drinking beer and eating noodles again without any problems.

Now I have to take an antibiotic that targets the digestive tract every 1 - 1.5 years as symptoms return. This indicates that my problem is bacterial rather than parasitic, although the exact cause of my problem hasn't been identified.

An interesting side note: I traveled to Japan while affected by gluten (but before corn became problematic), and I ate in restaurants the whole trip with only one problem. I am certain that I was consuming small amounts of gluten with each meal. I learned that Japan and other countries have rejected US wheat shipments over certian GMOs, but I couldn't reliably explain why I was largely unaffected in Japan.