A new study has found that both regular and organic dark chocolate contain traces of heavy metals, including lead and cadmium.
The study specifically warns against organic dark chocolate, which contains higher amounts of toxic metals than the types of non-organic dark chocolate tested in the study.
“The results of our analysis suggest that many products contain lead and cadmium in amounts that may exceed some stringent regulatory requirements,” the researchers wrote. “Therefore, enhanced monitoring may be warranted. Furthermore, additional research on cumulative exposure to heavy metals through the diet as a whole would help put this work into context to better inform public health policies and interventions.”
An overview of the study
To better understand the heavy metal content of dark chocolate, researchers tested 72 cocoa products purchased in retail stores between 2014 and 2022.
All samples were tested for lead, cadmium, and arsenic. The researchers used California Proposition 65 guidelines, which set maximum permissible dose levels (MADLs) for each of the heavy metals: 0.5 mcg/day for lead, 4.1 mcg/day for cadmium, and 10 mcg/day for arsenic.
Although none of the samples tested had arsenic levels above the MADLs, lead and cadmium were present in much higher amounts. More than 40% of the samples exceeded the MADLs for lead, while 35% of the samples exceeded the MADLs for cadmium.
The study also found that median concentrations of each of the metals tested were below the MADLs set by California law.
“This indicates that heavy metal contamination in the majority of products studied may not pose a risk to the average person when consumed as a single serving; however, consumption of more than one serving per day and/or in combination with other sources of heavy metals (e.g., seafood) may result in cumulative exposure exceeding the Proposition 65 MADLs,” the researchers explained.
The researchers also found that organic dark chocolate contained higher levels of lead and cadmium than non-organic samples. While many consumers choose organic chocolate because they believe it is a higher quality product, this study highlights that this is not always the case.
What are the health risks?
Although researchers explained that healthy adults should not be at significant risk of health complications from consuming dark chocolate in moderation, there are still some health risks to be aware of.
The study indicates that cadmium consumption increases the risk of cardiovascular disease, diabetes, osteoporosis, kidney dysfunction, cancer, cognitive decline, etc. In addition, vulnerable populations – children, pregnant women, adults with pre-existing health conditions – should be cautious about consuming foods containing traces of heavy metals.
