Effect of oxidation state and chelating agent on iron bio-accessibility from different commercial iron-supplements

Oral iron-supplementation represents the most common treatment for iron deficiency, a widely diffused mineral insufficiency. Seven commercial products containing different chelating agents (i.e. lipidic Fe (III)-pyrophosphate, Fe (III)-pyrophosphate, lipidic Fe (II)-sulphate, Fe (III)-saccharate and Fe (III)-EDTA) were analyzed. Infrared and thermal analyses highlighted that ferrous ions complexes were able to strictly interact with ascorbic acid thus forming stable soluble systems. Dynamic light scattering (DLS) analysis pointed out that lipidic Fe (II)-sulphate formulation showed the largest particle size (i.e. 184 nm against 120 nm found for lipidic Fe (III)-pyrophosphate based formulations) but showed the lowest PDI (0.25 against 0.30) that was not subjected to change after 7 days. Moreover, lipidic Fe (II)-sulphate formulation guaranteed a better bioavailability of iron using Caco-2 Cell model, permitting the absorption of more than 40% of administered iron against 20–30% found for formulations containing Fe (III) ions.