Study Occurrence of heavy metals coupled with elevated levels of essential elements in chocolates: Health risk assessment (May 2024)

Michael Harrop

Active member
Jul 6, 2023

This study makes super bizarre/absurd claims.

Consuming an ounce of dark chocolate daily poses no health concern for adults, with only minor concern for Cd in children

There is no safe level of lead

Article title:
A dark side to dark chocolate? New study finds very minimal risk for kids from metals in chocolates

I went to the funding and conflict of interest sections and see:
Funding source
We would like to thank the start-up fund granted to the first author from Tulane University that supported the research.

Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

So these are just super-fans of chocolate? Or they have too much lead in their brains?


  • Excluding Pb, Th and U, metals Mg, Zn, Cu, Ni, Sr, Co, Mn, Cd, and Tl in chocolates are mainly derived from cacao beans.
  • Central and South America chocolates had high Cd and Pb, while West Africa and Asia had low Cd and Pb, respectively.
  • Consuming an ounce of dark chocolate daily poses no health concern for adults, with only minor concern for Cd in children.
  • Dark chocolates contained significant levels of Cu, Fe, Mn, Mg and Zn that can also restrict bioavailability of Cd and Pb.
  • The study informs about cacao origins with low toxic metals and abundant essential elements for food safety and nutrition.


The presence of contaminants in cacao-derived products, especially in chocolates, has raised concerns regarding food safety and human health. The study assessed the concentration variation of 16 elements in 155 chocolate samples from the US market by cacao content and country of geographic origin. The study further examined the potential health risks posed by toxic metals and determined the contribution of essential elements to the Daily Recommended Intake (DRI), estimated based on an ounce (∼28.4 g) of daily chocolate consumption.

Dark chocolates with ≥50 % cacao exhibited consecutively increasing mean levels from 1.2 to 391 µg/kg for U, Tl, Th, As, Pb, Se, Cd, and Co. Similarly, Ni, Sr, Cu, Mn, Zn, Fe, Ca, and Mg had mean concentrations from 4.0 to 1890 mg/kg. Dark chocolates sourced from Central and South America exhibited the highest mean levels of Cd, and South America samples also contained elevated Pb, whereas those from West Africa and Asia had low Cd and Pb, respectively. Cacao contents showed increasingly strong association with Cd, Co, Mn, Sr, Ni, Cu, Zn, and Mg (r = 0.60–0.84), and moderately with Se, Fe, As, and Tl (r = 0.35–0.49), indicating these elements are primarily derived from cacao beans. Weak association of cacao contents with Pb, Th, and U levels (r < 0.25), indicates post-harvest contaminations. Hazard Quotient (HQ) > 1 was found only for Cd in 4 dark chocolates, and Hazard Index (HI) > 1 for cumulative risk of Cd, Pb, Ni, As, and U was found in 33 dark chocolates, indicating potential non-carcinogenic risks for 15 kg children but none for 70 kg adults. Dark chocolate also substantially contributed to 47–95 % of the DRI of Cu for children and 50 % for adults. Dark chocolates also provided notable Fe, Mn, Mg, and Zn contributions to the DRI. These essential elements are recognized to reduce the bioavailability of toxic metals such as Cd, Pb, or Ni, thereby potentially lowering associated health risks.

This study informs consumers, food industries, and regulatory agencies to target cacao origins or chocolate brands with lower toxic metal contents for food safety and minimizing adverse health effects.
Format correct?
  1. Yes