Bioavailability of iron from novel hydrogen reduced iron powders: Studies in Caco-2 cells and rat model

The bioavailability of iron from elemental iron powders, including hydrogen reduced iron powder (HRIP), is influenced by particle size and surface area. In the present study, we investigated the solubility, bioaccessibility, and bioavailability of iron from novel HRIPs (particle size ≤25 and 38 µm generated at low [LT] and high [HT] temperature), with porous morphology and high surface area, in intestinal Caco-2 cells and in rat models. The acceptability of fortified wheat flour was tested in human volunteers. The iron solubility and ferritin induction in Caco-2 cells were significantly higher from wheat flour fortified with HRIPs compared to electrolytic iron powder (EIP, ≤45 µm size) either in the absence or presence of ascorbic acid. Nevertheless, ferritin induction in Caco-2 cells was significantly higher with FeSO₄ compared to HRIP or EIP. The relative biological value of HRIPs was significantly higher (≤38HT) or similar compared to EIP in rats. However, serum ferritin was significantly higher in rats fed HRIPs than EIP. Further, wheat flour fortified with HRIP was found to be acceptable for consumption. These findings demonstrate higher iron bioavailability from novel HRIPs compared to the reference EIP (≤45 µm) and merits further studies on toxicity and efficacy. PRACTICAL APPLICATION: The use of elemental iron powders for food fortification to alleviate iron deficiency is limited due to its poor bioavailability. The novel hydrogen-reduced elemental iron powders used in this study had higher bioaccessibility and bioavailability compared to reference EIP (≤45 µm) in in vitro and in vivo models, respectively. Further, there were no sensory differences between roti prepared with fortified or unfortified wheat flour. These results suggest that the novel hydrogen reduced elemental iron powders used in the present study are suitable for wheat flour fortification.