This is a bit of the point of your original question, but I am wondering if you have a blood glucose meter?

Anything that you eat that sends your blood glucose above 140 can contribute to PN. The bloodsugar101 website has details on this and how to use test strips economically.

The reason I mention this is that eliminating gluten may not be enough, but the meter can help you determine if you're having trouble with any other foods in an inexpensive way.