Universidad de Córdoba BIODISPONIBILIDAD MINERAL DE ...

Biodisponibilidad mineral de menús escolares
Finally, with respect to calcium, some studies have shown that calcium
chloride inhibits heme iron absorption in the same extension as non heme iron
(Hallberg et al., 1991). This shows that calcium may interact with iron
absorption in a step during absorption common to heme and non heme iron
(Hallberg et al., 1992) and it has a direct effect on heme iron absorption,
counteracting the enhancing effect of meat (Bendich, 2001). It has been
demonstrated that this inhibitory effect depends on the dose, so dose below 40
mg does not have inhibitory effect, while maximum inhibition is reached with
intakes around 300 mg where it ends up being of 50-60% suggesting an
incomplete blockade of iron absorption (Hallberg et al., 1991; Gleerup et al.,
1995; Hallberg, 1998).
Non-heme iron availability: dietary factors
Non heme iron absorption is conditioned by multitude of factors as the
chemical form in which is present in the food (in ferrous state it is absorbed
much better than in ferric state), iron intake present in the food, as well as by
the presence of certain enhancers and inhibitors. Non heme iron absorption will
be conditioned by its solubility in intestinal lumen (Kim et al., 1995), so all those
substances that increase this solubility would be considered as enhancers
whereas compounds that diminish solubility of this element would be
considered as inhibitors.
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