Universidad de Córdoba BIODISPONIBILIDAD MINERAL DE ...

Biodisponibilidad mineral de menús escolares
1989; Chabance et al., 1998) that iron bound to β-caseinophosphopeptides
could be absorbed by a different pathway from that observed with non-heme
iron. Pérès et al. (1999b) studied iron bound to β-caseinophosphopeptides or
iron gluconate absorption by using a perfused vascularized duodenal rat loop
model. In order to see how these compounds were absorbed, experiments
were carried out in the presence of an inhibitor of endocytosis, i.e. phenylarsine
oxide, an inhibitor of oxidative phosphorylation, i.e. 2, 4-dinitrophenol and both
inhibitory agents. The results showed that 2, 4-dinitrophenol inhibited oxidative
phosphorylation in both gluconate and caseinophosphopeptide, proving that
these salts are absorbed through active transport. After energy-dependent
processes were abolished, passive absorption could be of physiologic
importance because it depends on intraluminal concentrations and escapes
from homeostatic control, however passive iron absorption was not enhanced
by β-caseinophosphopeptide. Finally, phenylarsine oxide inhibited iron
absorption bound to β-caseinophosphopeptide but not to gluconate, so only part
of β-caseinophosphopeptide-ion is absorbed by endocytosis, in addition to the
usual passive and active transport; it may be the reason to explain the enhance
on iron bioavailability.
This specific pathway absorption could also justify previous studies which
have pointed out that iron bound to caseinophosphopeptides also prevents from
interactions between iron and other minerals such as calcium and zinc (Pérès et
al., 1997; Aït-oukhatar et al., 1997; Pérès et al., 1999a). This effect has been
observed in rats; a lower interaction Fe-Zn than usual was observed when iron
142