Content and daily intake of copper, zinc, lead, cadmium, and mercury from dietary supplements in Mexico

This study investigates the presence of Cu, Zn, Cd, Pb, and Hg in 24 dietary supplements purchased in different health stores across the city of Hermosillo, located in the northwest of Mexico. Analysis of metals was done by microwave digestion and atomic absorption spectroscopy. The most abundant elements in dietary supplements were Cu (<0.19–137.85 μg/g) and Zn (<2.83–4785.71 μg/g), followed by Pb (<0.003–66.32 μg/g), Cd (<0.001–2.90 μg/g), and Hg (<0.24–0.85 μg/g). The estimated daily intakes of metals were below those recommended by WHO and the Institute of Medicine, showing that little risk from heavy metals is associated with the consumption of the dietary supplements analyzed. However, some products presented more than 10% of the tolerable daily intake of Pb, indicating that production processes should be improved.