Adrien,
Just some specificity here. The Swiss in Price's study didn't eat cereal products, they supplemented their diet of meat, dairy and vegetables with one --- whole rye bread. The Scots didn't eat cereal products: they supplemented their fish-based diet with one, a whole oat. They were not eating grain-based diets.
Egyptian mummies show massive and catastrophic examples of tooth decay as well as other diseases of bone degeneration. Their diet was hugely wheat-based.
j