I have recently run into medical discussions that high fructose intake may be causative for inflammatory responses in the human body. It seems that it has the same strength of impact as gluten. Diets have become generally higher in fructose because of the addition of corn syrup.

However fructose accumulation is a metabolical response of diverse crops to stress. It may well be, that a happy, minerally balanced crop in aerated soil is not causing inflammation despite the same genetic makeup.

And it may well be that ancient varieties/crops that are not so demanding do thrive better and unstressed in moderate fertility (plus they probably contain many secondary metabolites that work as modulators for the immune system).