It's possible that you are struggling to find evidence because the evidence points in the other direction. For example, from the review article you linked:

"Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet."

Step 1 of fostering "shoshin" was to explain a theory or idea to someone else. Now step 2 is to stay aware of confirmation bias.