Iron availability of a fortified processed wheat cereal: a comparison of fourteen iron forms using an in vitro digestion/human colonic adenocarcinoma (CaCo-2) cell model

Abstract

In this three-phase study we first compared the availability of fourteen Fe forms in a wheat-based ready-to-eat breakfast cereal using an in vitro digestion/human colonic adenocarcinoma (CaCo-2) cell model. We then investigated the effect of milk and/or coffee on those fortified cereals found in phase 1 to show promising increases in Fe availability. The Fe forms assessed in phase 1 were reduced (control), carbonyl, electrolytic, FePO 4 , FeSO 4 , FeCO 3 , Na 2 FeEDTA, Ferrochel ® (Albion Laboratories, Clearfield, UT, USA; ferrous bis-glycinate), encapsulated ferrous fumarate, FeSO 4 , ferrous lactate and Biofer ® (LipoTech, Britwell Salome, Oxfordshire; FeSO 4 ), SQM ® (Sea-Questra-Min Iron; Quali Tech, Chaska, MN, USA; polysaccharide-complexed FeSO 4 ) and Sun Active ® (Taiyo Kagaku, Yokkaichi, Japan). All these forms increased Fe uptake compared with the unfortified cereal. Relative to the control, the following increases in Fe availability were observed: electrolytic, 52 %; ferrous fumarate, 30–35 %; Sun Active, 78 %; Ferrochel, 125 %; Na 2 FeEDTA, 291 %. Recent human studies have shown similar data with regard to Ferrochel, FeSO 4 and Na 2 FeEDTA, with the latter being more bioavailable. Our phase-2 studies indicated that the addition of milk to FeSO 4 -fortified cereal increased Fe availability, but this availability was markedly decreased by the addition of coffee to the digest. Conversely, a loss in availability from Na 2 FeEDTA was observed with the addition of milk; however, the addition of coffee did not markedly affect Fe availability from this form. In phase-3 studies we observed increased Fe availability upon the addition of milk to cereals containing Ferrochel, FeSO 4 , Sun Active, a mixture of reduced Fe and Na 2 FeEDTA or reduced Fe. For these forms we did not assess the behaviour after the addition of coffee. In conclusion, when considering possible fortificants for optimizing Fe bioavailability within a foodstuff, it is of paramount importance to consider the interaction between the fortified foodstuffs and other components of the meal (such as milk and coffee with a breakfast).