First, Matt Lalonde Ph.D's video "The Science Behind the Paleolithic Diet."
The title of this post comes from Matt Lalonde. As mentioned in Keep 'em tight., about 10% of healthy blood donors have antibodies in their blood to something that shouldn't be in their blood - gliadin. How do gliadin fragments get into the blood? Compromised gut integrity (a.k.a. Leaky gut).
It's possible to repair compromised gut integrity, as mentioned in the above post. In the meantime, it's advisable to avoid "problem proteins" and eat only "safe proteins". Which proteins are the problem?
1) Prolamines: Prolamines are a group of plant storage proteins having a high proline content and found in the seeds of cereal grains: wheat (gliadin), barley (hordein), rye (secalin), corn (zein), sorghum (kafirin) and as a minor protein, avenin in oats.
2) Casein: Of the six major protein types in cow's milk, four are casein proteins
and the other two are whey proteins. The caseins usually make up about
80% of the protein in cow's milk. Cheese is ~100% caseins. As Matt said, caseins are also high in proline. Whey is rapidly digested (which is why it's used by bodybuilders post-workout) so it's pretty safe.
3) Anything that makes you feel ill: As everyone is different, this could be anything (peanuts, eggs, shellfish, tomatoes etc). If "X" makes you feel ill, stop eating "X" until your gut is working 100% correctly. There's a possibility that your gut will never work 100% correctly. Which proteins are safe?
Rice, quinoa & amaranth contain generally safe proteins. Properly-cooked legumes (peas, beans & lentils) contain generally safe proteins. Seeds contain generally safe proteins, but most types are very high in omega-6 fats (except for chia & linseeds). Tubers, root veggies & buckwheat contain pretty safe proteins. Meats & fish contain pretty safe proteins.
Pigging-out on safe proteins, (resulting in significant amounts of incompletely-digested proteins reaching the lower intestine) is asking for trouble. Ditto for eating excessive amounts of fruit with or shortly after eating safe proteins, as this increases the speed of peristalsis, which increases the amount of incompletely-digested proteins reaching the lower intestine.
That's all for now. If anything else comes to mind (or if you come up with a bright idea), I'll add it.