Ferric iron

Fe3+

Ferric iron is the trivalent oxidation state of iron. It is largely insoluble and therefore biologically unavailable (Wallace, 2016, Yiannikourides & Latunde-Dada, 2019). In low pH of gastric acid ferric iron is reduced to ferrous iron (Fe2+), which is more easily absorbed than Fe3+ (Abbaspour et al., 2014).