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Iron from nanostructured ferric phosphate: absorption and biodistribution in mice and bioavailability in iron deficient anemic women

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Jeannine Baumgartner, Hans Christian Winkler, Lizelle Zandberg, Siriporn Tuntipopipat, Phatchari Mankong, Cor Bester, Florentine Hilty, Jan Rijn Zeevaart, Sueppong Gowachirapant, Michael B. Zimmermann

Original languageEnglish
Article number2792
JournalScientific Reports
Issue number1
Early online date18 Feb 2022
Accepted/In press20 Jan 2022
E-pub ahead of print18 Feb 2022
PublishedDec 2022

Bibliographical note

Funding Information: Swiss National Science Foundation (SNSF), National Research Program 64 “Opportunities and risks of nanomaterials”, no. 406440-141610; and ETH Zurich, Zurich, Switzerland. Funding Information: We thank L von Moos, C Zeder, A Krzystek, C Blattmann, S Pratsinis (ETH Zurich, Switzerland), J Erhardt (Willstaett, Germany) for assistance in the production of the iron compounds, their characterization and laboratory and data analysis. We thank E Schraner (University of Zurich, Switzerland) for assistance with TEM. We thank K Venter (NWU, South Africa) for assistance in the execution of the animal experiments at NWU and Necsa. We thank J Gama (Necsa, South Africa) for the surface area determination of the irradiated NP and GS Smith (Necsa) for associated radiation protection making this possible. We thank the Thai women who participated in the study, and thank A Boonpraderm and S Rattarengsak (INMU, Thailand) for assistance with the test meals. This work was supported by the Swiss National Science Foundation (SNSF), National Research Program 64 ?Opportunities and risks of nanomaterials?, no. 406440-141610; and ETH Zurich, Zurich, Switzerland. Publisher Copyright: © 2022, The Author(s).

King's Authors


Food fortification with iron nanoparticles (NPs) could help prevent iron deficiency anemia, but the absorption pathway and biodistribution of iron-NPs and their bioavailability in humans is unclear. Dietary non-heme iron is physiologically absorbed via the divalent metal transporter-1 (DMT1) pathway. Using radio- iron isotope labelling in mice with a partial knockdown of intestine-specific DMT1, we assessed oral absorption and tissue biodistribution of nanostructured ferric phosphate (FePO4-NP; specific surface area [SSA] 98 m2g-1) compared to to ferrous sulfate (FeSO4), the reference compound. We show that absorption of iron from FePO4-NP appears to be largely DMT1 dependent and that its biodistribution after absorption is similar to that from FeSO4, without abnormal deposition of iron in the reticuloendothelial system. Furthermore, we demonstrate high bioavailability from iron NPs in iron deficient anemic women in a randomized, cross-over study using stable-isotope labelling: absorption and subsequent erythrocyte iron utilization from two 57Fe-labeled FePO4-NP with SSAs of 98 m2g−1 and 188 m2g−1 was 2.8-fold and 5.4-fold higher than from bulk FePO4 with an SSA of 25 m2g−1 (P < 0.001) when added to a rice and vegetable meal consumed by iron deficient anemic women. The FePO4-NP 188 m2g-1 achieved 72% relative bioavailability compared to FeSO4. These data suggest FePO4-NPs may be useful for nutritional applications.

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