(311f) Iron Fortification: Flame-Made Nanostructured Mg- or Ca-Doped Fe Oxides

Iron deficiency affects
approximately 2 billion people worldwide, especially young women and children.
Food fortification with iron is a sustainable approach to alleviate iron
deficiency but remains a challenge. Water-soluble compounds with high
bioavailability (e.g. the ?gold standard? FeSO₄) usually cause
unacceptable sensory changes in foods, while compounds that are less reactive
in food matrices are often less bioavailable [1]. Solubility (and therefore
bioavailability) can be improved by increasing the specific surface area (SSA)
of the compound, i.e. decreasing its particle size to the nm range. Rohner et
al. [2] prepared nanostructured FePO₄ by flame spray pyrolysis (FSP)
with SSA as high as 195 m²/g (~11 nm) that exhibited high solubility
and bioavailability comparable to FeSO₄ (the ?gold standard? as
supplement to alleviate iron deficiency) in Sprague-Dawley rats but with
improved sensory properties. Recently Hilty et al. [3] developed
zinc-containing nanostructured iron compounds with nutritionally attractive
Zn-compounds by FSP. The addition of Zn increased iron solubility and (as shown
recently) bioavailability that was comparable to FeSO₄ but with
improved sensory (color) properties [4]. Bioavailability was determined in-vivo
by actual administration of these fortificants to rats, where no adverse
effects in organs and tissues were found. Additional doping of Zn/Fe oxide with
Mg increased Fe absorption and improved powder color [4]. Here, iron
oxide-based nanostructured compounds with Mg or Ca are made using FSP [5].
Addition of either element increased iron solubility to a level comparable to
iron phosphate. Furthermore, these additions lightened the powder color and
sensory changes in fruit yoghurt were less prominent than for FeSO₄.

[1]  Hurrell RF. Fortification: Overcoming technical
and practical barriers, Journal of Nutrition (2002), 132,
806S-812S.

[2]  Rohner F, Ernst FO, Arnold M, Hilbe M, Biebinger R, Ehrensperger
F, Pratsinis SE, Langhans W, Hurrell RF & Zimmermann MB. Synthesis,
characterization, and bioavailability in rats of ferric phosphate
nanoparticles, Journal of Nutrition (2007), 137, 614-619.

[3] Hilty FM, Teleki A, Krumeich F, Buchel R,
Hurrell RF, Pratsinis SE & Zimmermann MB. Development and
optimization of iron- and zinc-containing nanostructured powders for
nutritional applications, Nanotechnology (2009), 20, 475101.

[4]  Hilty FM, Arnold M, Hilbe M, Teleki A, Knijnenburg JTN,
Ehrensperger F, Hurrell RF, Pratsinis SE, Langhans W & Zimmermann MB. Iron from nanocompounds containing iron and zinc is highly
bioavailable in rats without tissue accumulation, Nature Nanotechnology (2010),
published online Apr 25, http://dx.doi.org/10.1038/nnano.2010.79.

[5] Hilty FM, Knijnenburg JTN, Teleki A, Krumeich
F, Hurrell RF, Pratsinis SE & Zimmermann MB. Addition of Mg and Ca to
nanostructured Fe₂O₃ improves solubility in dilute acid
and sensory characteristics in food, Journal of Food Science (2010), submitted.