Universidad de Córdoba BIODISPONIBILIDAD MINERAL DE ...

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Zinc corporal content
One of the main conditioning factors of zinc availability is the status of this
trace element of an individual. Studies about zinc absorption carried out in
children, using meals labeled with the stable isotopes 67 Zn and 70 Zn, indicated
that the fraction of zinc absorbed was dependent on the previous diet of the
child, and the percentage of zinc absorption was higher in children who had
been fed previously with smaller levels of zinc (Serfass et al., 1989; Ziegler et
al., 1989).
Wada et al (1985) made similar studies with stable isotopes in
young men and found that zinc percentage absorption was 53% when the zinc
intake in the diet was 5,5 mg per day and that it decreased to 25% when was
16.5 mg per day and August et al (1989) found in young adult subjects that zinc
percentage absorption was about 64% when the zinc content in the diet was
2.8-5 mg per day, but only 39% when it contained 12.8-15 mg per day. Other
experiences point out that homeostasis regulation of zinc during low zinc intake
periods is due to a marked decrease of endogenous zinc secretion instead of
an increase in absorption of this element (Lee et al,1993; Sian et al, 1996).
In this respect, one of the main problems is to determine the corporal
status of zinc, because there is not an universally accepted indicator. In
epidemiological studies to determine the individual status of zinc, the plasmatic
fraction of this element has been used as an indicator, despite it being known
that this element trace is mainly situated inside the cell. This plasma zinc
content is homeostatically regulated and also affected by others factors (diurnal
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