RESUMO
BACKGROUND: Peptides derived from cow's milk proteins have in vitro protective effects on iron-induced peroxidation that could be used to prevent the side effects of iron fortification. The aim of the study was to confirm these properties in an in vivo model of gut peroxidation. METHODS: Iron bound to the 1-25 phosphopeptide of beta-casein [Fe-beta-CPP(1-25)] was compared to an encapsulated ferric pyrophosphate (Fe-P) in the Caco-2 model. Ferrous sulfate (FeSO(4)) was used as control (100 micromol/l iron, n = 6 per group). The concentration of malondialdehyde (MDA), a stable byproduct of lipid peroxidation, was used as the marker of peroxidation. RESULTS: The lowest MDA levels were observed in cells grown with Fe-beta-CPP(1-25) and the highest with Fe-P. Iron absorption of Fe-beta-CPP(1-25) was higher than in the 2 other forms, due to its high cellular uptake and high basolateral transfer, while iron absorption of Fe-P showed high uptake and high cell retention. CONCLUSIONS: The enhancing effect of beta-CPP(1-25) on iron absorption was associated with a protective effect against enterocyte peroxidation, perhaps due to its low storage by enterocytes. These observations support a role for specific milk components in food fortification to prevent iron deficiency.