A new study has found that many dark chocolate products currently on the U.S. market are contaminated with toxic heavy metals like lead and cadmium.
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Researchers at George Washington University tested 72 consumer cocoa products, including dark chocolate, every two years over an eight-year period for lead, cadmium and arsenic.
Their new study, published by Nutrition Frontiersfound that 43 percent of products exceeded the maximum allowable dose for lead, 35 percent exceeded the maximum allowable dose for cadmium, and organic products had higher levels than non-organic products.
None of the products exceeded the maximum permitted dose of arsenic.
Leigh Frame, director of integrative medicine and associate professor of clinical research and leadership, and Jacob Hands, a medical student researcher in the Frame-Corr lab — both at the George Washington School of Medicine and Health Sciences — led the study.
The team partnered with ConsumerLab, a company that independently tests and evaluates health and nutrition products, and purchased the chocolate for the study from third-party online retailers like Amazon and iHerb, brick-and-mortar retailers like GNC and Whole Foods, and manufacturer and distributor websites. The brands tested are not listed in the study.
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Lead Found in Other U.S. Food Products
Adobe Stock The study authors said that in moderation, the risk is still low, but the results warrant further investigation.
Cadmium can cause cancer and can also negatively impact the cardiovascular, neurological, respiratory and reproductive systems.
According to the U.S. Food and Drug Administration (FDA), “there is no safe level of lead exposure,” and ingesting even small amounts can have adverse health effects. Yet this highly toxic heavy metal continues to appear in American foods.
In the second half of 2023, lead-contaminated applesauce bags caused several cases of lead poisoning before being recalled. In March 2024, the FDA found elevated levels of lead in some ground cinnamon products and advised the public not to purchase them.
Then, in April, Consumer Reports Advocacy called on the USDA to remove Kraft Heinz Lunchables from the federal school lunch program after finding they contained “relatively high levels of lead and cadmium” and “concerning levels” of harmful chemicals.
“We all love chocolate, but it’s important to consume it in moderation, as with other foods that contain heavy metals, including large fish like tuna and unwashed brown rice,” Frame said of the new study’s findings on cocoa products. “While it’s not practical to completely avoid heavy metals in your diet, you should be mindful of what you eat and how much you consume.”
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