Zinc, an essential trace mineral, is one of the nutrients at risk of deficit in children. Zinc absorption decreases in the presence of phytates, and there is controversy about the effect of calcium on zinc absorption in humans. The aim of the study was to evaluate the effect of calcium on the absorption of zinc.
Experimental study, each subject was his own control. Stable isotopes of zinc were used for the study. The protocol was approved by the Ethics Committee of INTA and subjects signed informed consent. 14 subjects, 6 males and 8 healthy women were recruited between 18-35 years (mean ± SD of 24.9 ± 2.2 years and BMI of 23.8 ± 3).On day 1, after an overnight fast hair and a blood sample was taken to measure zinc status, and was injected a dose of 70zinc to determine the zinc retained in basal conditions; then an oral dose of 10 mg of zinc was administered (8 mg of zinc as ZnSO4 and 2 mg 67Zn). On day 2, after an overnight fast an oral dose of 10 mg zinc was administered; (6 mg zinc as ZnSO4 + 4 mg of 68Zn) plus 650 mg calcium as CaCO3. Urine was collected days 4-6 to measure the excretion of isotope by mass spectrometry (ICP-MS) and absorption estimate.
None of the subjects was deficient in zinc and a woman had anemia only. Mean ± SD of serum zinc was 79.5 ± 6.4 (maximum range 70-93 ug/dL). The mean ± SD of percentage Zn absorption of zinc without and with calcium were 48.1 ± 9.4% and 60.3 ± 19.8%, respectively (NS).
According to the results, we can conclude that calcium does not affect the absorption of zinc