The form of iron "supplementation" universally added to flour in the US is little more than that. There's some theories that this impacts gut bacteria, particularly the ones associated with B-vitamin.
Iron shavings -> bad bacteria -> poor Vitamin B status -> intestinal lining damage -> celiac, allergies and autoimmune
TLDR; bread in the US makes people sick, not in Europe
Iron shavings -> bad bacteria -> poor Vitamin B status -> intestinal lining damage -> celiac, allergies and autoimmune
TLDR; bread in the US makes people sick, not in Europe