Here’s the reality of human physiology; we will NEVER understand how complicated it is. Gluten sensitivity’s effect on the brain falls under this category.
There’s no doubt that many of us has a grasp on small amounts of how the body works, but the big picture is just too big for any one of us to understand fully. It’s kind of like–I can drive around here in Phoenix quite well and know where I’m at or at least how to get to where I need to go. But drop my in Dubai without a map or GPS and I’m pretty much screwed (especially since my Arabic is a little rusty…).