Content and daily intake of copper, zinc, lead, cadmium, and mercury from dietary supplements in Mexico.
Level 5 - mechanism / opinion, no new human data
Laboratory chemical analysis of commercial products without human subjects
PubMed 17418927 · doi:10.1016/j.fct.2007.02.027
What was done
Researchers analyzed 24 dietary supplements purchased from health stores across Hermosillo, Mexico, to determine the concentrations of copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), and mercury (Hg). Elemental analysis was performed using microwave digestion and atomic absorption spectroscopy. The estimated daily intakes of these metals were calculated and compared against safety standards established by the World Health Organization (WHO) and the Institute of Medicine.
What was found
The element concentration ranges across the 24 dietary supplements were: - Copper: <0.19 to 137.85 µg/g - Zinc: <2.83 to 4785.71 µg/g - Lead: <0.003 to 66.32 µg/g - Cadmium: <0.001 to 2.90 µg/g - Mercury: <0.24 to 0.85 µg/g Estimated daily intakes of all evaluated metals were below WHO and Institute of Medicine recommended limits, though certain products accounted for more than 10% of the tolerable daily intake for lead.
Why it matters
This study provides direct quantitative screening data on trace and heavy metal levels in over-the-counter supplements in Mexico, identifying potential manufacturing quality issues where lead levels approach notable fractions of tolerable daily intakes.
Limits
The analysis was limited to 24 supplement samples gathered exclusively within a single city (Hermosillo). The abstract does not specify the specific ingredients or formulations tested, and potential risks were evaluated via modeled intake calculations rather than human exposure biomonitoring.
Cited by
- supports Food products purchased from health food stores often contain heavy metals such as lead, cadmium, and mercury.