my theory - after zero seconds of internet research
it has something to do with what's in our fertilizer...
perhaps it all boils down to all the antibiotics that are fed to the animals
wonder if there is anything similar in China - since much of our fertilizer is exported there
but a few seconds of search found this interesting New Yorker article on gluten and gluten insensitivity (from about a year ago)
https://www.newyorker.com/magazine/2014/11/03/grain
It's a hybrid wheat. About 100 years ago, iirc, a super wheat was created and that's when the problems started.
Also, everything is just more discussed and communicated today than centuries or even decades ago. Durr