Bread has been a staple for thousands of years....Now in the last 5 years it has become EEEvil. Me thinks there is something wrong with people, not wheat.
Not every variety of human can get along with wheat. The number usually tossed out is 1% for Europeans. Many other groups we just don't know about because they don't consume wheat and have no idea what it is. There are other grain allergies. For example 10% of Japanese can't get along with rice!
Then there are Americans! We got everybody here, but not all in equal measure. 3.5% (app) of adult Americans are intolerant of wheat according to the Celiac researchers at University of Maryland. Virtually no black people have that problem, and then there's an equally large number who haven't been studied because they use corn as their primary staple ~ (raises hand).
Part of the reason for the increased level of gluten intolerance arises from the 'founder effect' ~ and we have that in spades. The Scandinavian Sa'ami people appear to have been isolated from the rests of Europe for a good 18,000 years ~ they've become a genetic isolate and they retain many genetic components common in the European Cro-Magnon ancestry that arrived 35,000 years ago.
The Cro-Magnon hunter gatherers, and the Sa'ami up to 1,000 years ago, simply had no contact with wheat. We do know humans have to genetically adapt around a new food like wheat ~ and that's not yet happened with the Sa'ami.
Thanks to the Swedish Empire the Sapma where the Sa'ami live, was almost depopulated as they were shipped to America! Being among the first European settlers in this country they had more time to adapt and spread and become a far larger percentage of the new American nation than would otherwise be expected.
3.5% means there are at least 9,000,000 folks here with the genes for Celiac ~ but not all people with those genes express the disease in their younger years. On the other hand, that means the Sa'ami ~ or part-Sa'ami ~ people in this country are a large minority ethnic group which is virtually invisible due to the large percentage of blonds among them.