In vivo study of the effect of lactoferrin on iron metabolism and bioavailability from different iron chemical species for formula milk fortification

Iron fortification in infant formulas is a common practice for providing iron to newborns in order to avoid its deficiency (anemia). Depending on the physicochemical species used, its bioavailability might be insufficient to meet iron requirements. In this vein, the influence of Lactoferrin (Lf) presence on iron bioavailability in 2-week-old wistar rats fed with formula milk fortified with Fe-57(III)(2)-Lf or Fe-57(II)SO4 (in presence of Lf) using quantitative speciation (by HPLC-ICP-MS) and Isotope Pattern Deconvolution (IPD) is studied here. Results obtained were compared among fortifiers and also with the maternal group. In RBCs, iron was mainly bound to hemoglobin in all the assayed groups in the same extent. Regarding serum samples, several iron-proteins were observed (such as transferrin and albumin). In both samples, iron content in the fractions studied was similar in all groups compared and exogenous Fe-57 incorporation of intaked iron was always above 50%, showing no significative differences between physicochemical forms but related to the dose administered. Regarding iron stores (liver) the group fed with formula milk fortified with the higher dose of (FeSO4)-Fe-57 in presence of Lf presented the highest values of total iron even superior than those found in the maternal group, and also the highest exogenous (Fe-57) incorporation. In conclusion, it was proved that iron fortification is required to ensure proper iron levels in all body compartments. No significative differences were observed between different physicochemical species when iron is administered at low doses. However, higher iron doses lead to a greater incorporation in all the iron-proteins studied.