Characterization of Key Factors of Anchovy (Engraulis japonicus) Meat in the Nanoparticle-Mediated Enhancement of Non-Heme Iron Absorption.

Anchovy (Engraulis japonicus) meat (AM) has been shown to promote nonheme iron absorption via a ferric oxyhydroxide nanoparticle (FeONP)-mediated mechanism. Here, formulation modifications of an egg-white-based AIN-93G diet with AM fractions resulted hemoglobin regeneration efficiencies in anemic rats following an order control (23.69 ± 3.99%) < ferrous-sulfate-replacement of ferric citrate (39.89 ± 2.97%) ≈ dehemeed-AM-protein-replacement of egg white (45.88 ± 4.76%) ≈ AM-lipid-replacement of soybean oil (43.14 ± 3.48%) ≈ chondroitin-sulfate-replacement of ∼2.5% corn starch (39.92 ± 1.88%) < l-α-phosphatidylcholine-replacement of ∼29% soybean oil (53.42 ± 2.04%), with nanosized iron enriched in proximal-small-intestinal contents by these AM fractions. The calcein-fluorescence-quenching assay in polarized Caco-2 cells revealed good iron absorption from FeONPs coated with AM peptides, l-α-phosphatidylcholine, l-α-lysophosphatidylcholine, and chondroitin sulfate, with the latter two disfavoring endocytosis thereby inducing relatively weaker iron absorption. These results suggest peptides, phospholipids, and mucopolysaccharides released during AM digestion are key factors promoting nonheme iron absorption.