Zinc Toxicity: Understanding the Limits.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing regulatory guidelines and toxicological mechanisms without primary data or systematic search methodology.
PubMed 38999082 · doi:10.3390/molecules29133130
What was done
This narrative review summarizes regulatory agency guidelines, tolerable upper intake levels (UL), mechanisms of toxicity, and alternative exposure routes (such as inhalation and topical application) for zinc.
What was found
The review reports that the World Health Organization (WHO) cites a dietary reference value of 6.7 to 15 mg per day. The European Food Safety Authority (EFSA) sets the tolerable upper intake level at 25 mg per day, whereas the Food and Drug Administration (FDA) sets it at 40 mg per day. Exceeding recommended intakes is noted to cause anemia, neutropenia, and zinc-induced copper deficiency. No primary experimental numbers or statistical analyses were generated.
Why it matters
It highlights notable discrepancies between international regulatory safety thresholds (25 vs. 40 mg per day) and warns of secondary risks like copper deficiency and non-oral toxicity.
Limits
As a narrative review, it presents no original empirical data, sample size, or systematic methodology. Specific quantitative exposure thresholds for non-oral routes are not provided in the abstract.
Cited by
- supports Taking zinc supplements over a long period depletes the body of copper.