Anecdotal and personal experience tells me that people with gluten intolerances (or any autoimmune diseases) should also avoid soy and corn due to possible cross-reactivity, leading to increased intestinal permeability.
I haven't been able to find any peer-reviewed evidence of this. Anybody know of any?
Here's one for maize/corn:
Plant Foods for Human Nutrition DOI: 10.1007/s11130-012-0274-4
Maize Prolamins Resistant to Peptic-tryptic Digestion Maintain Immune-recognition by IgA from Some Celiac Disease Patients
Francisco Cabrera-Chávez, Stefania Iametti, Matteo Miriani, Ana M. Calderón de la Barca, Gianfranco Mamone and Francesco Bonomi
"IgA from some celiac patients with HLA-DQ2 or DQ8 haplotypes recognized two alpha-zeins even after peptic/tryptic proteolysis. However, digestion affected zeins after denaturation, reduction, and alkylation, used for identification of prolamins as alpha-zein A20 and A30 by MS/MS sequencing. An in silico analysis indicated that other zeins contain similar sequences, or sequences that may bind even better to the HLA-DQ2/DQ8 molecules compared to the already identified ones.
Results concur to indicate that relative abundance of these zeins, along with factors affecting their resistance to proteolysis, may be of paramount clinical relevance, and the use of maize in the formulation and preparation of gluten-free foods must be reevaluated in some cases of celiac disease."
Japanese celiacs and soy sauce 2 Answers