INHIBITORY EFFECTS OF ZINC ON MAGNESIUM BALANCE AND MAGNESIUM ABSORPTION IN MAN

Objective: Both zinc (Zn) and magnesium (Mg) are widely used as nutrit ional supplements and the possibility was considered that Zn may inter fere with the absorption of Mg, similar to previously reported results [1,2] obtained with the same dose of supplemental Zn on the absorptio n of calcium (ca). Methods: Mg absorption studies and metabolic balanc es of Mg and of Zn were carried out in three groups of adult males in a metabolic research unit during the intake of supplemental doses of 1 42 mg Zn as Zn sulfate (ZnSO4) during Ca intakes of 230, 500 and 800 m g/day. Results: The Zn intake of 142 mg/day decreased the Mg balance a nd Mg absorption only during the 500 mg Ca intake compared to control values. However, the overall effect of the high Zn intake of the three groups combined, regardless of the Ca intake, was a highly significan t decrease of Mg absorption and of the Mg balance. Conclusion: Zn supp lements of 142 mg/day decreased Mg absorption and the Mg balance signi ficantly during all Ca intakes for the three groups combined.