The iron absorption
The iron absorption window is located in the small intestine. Iron absorption is performed by the villi of the duodenum and proximal jejunum.
The iron disposability of his reduced form (Fe 2 +) offers the great advantage to improve greatly the efficiency of its absorption.
The oxidized form (Fe 3 +) has many other disadvantages such as the precipitation with molecules like phytates and tannins which reduces even more its absorption.
It is recognized that the absorption of iron in its reduced form is about ten times better assimilated than the oxidized form.