This a bit of a long article ( but very interesting). I think it suggests that coeliacs are more highly evolved because their bodies are more adept at protecting themselves from wheat which the author claims is a toxic substance to everyone. The body protects itself by damaging the villi to decrease absorption and flushes the wheat through as quickly as possible ( diarrhoea ). The author also believes that for those who do not have this reaction, the damage caused by gluten can manifest in various other ways that would never be attributed to gluten intolerance.