Dark Chocolate: Lead and Cadmium

Photo Courtesy of Cleveland Clinic

Photo Courtesy of Cleveland Clinic

On December 15, 2022, Consumers Report published an investigation measuring the lead and cadmium concentrations in 28 brands of dark chocolate. The investigation found that all brands had small amounts of lead and cadmium. Assuming an adult ate one ounce of the brand a day, 23 brands surpassed the levels that California’s Proposition 65 allowed, and 5 surpassed those levels in both lead and cadmium. Ingested lead can cause damage to the neural system, slowed learning development, as well as hearing and speech problems. Cadmium can cause kidney damage, liver damage, birth defects and has been recognized as a cancer causing agent. This report applies to 15 percent of the United States population which reported eating dark chocolate everyday.

Cadmium is a mineral in the Earth’s soil that enters the cocoa plant naturally during its growth cycle. Lead contamination occurs while cocoa beans are being dried, fermented, and transported as dust brings lead onto the beans. However, lead and cadmium are not limited to dark chocolate. They can be found in other plant based products such as carrots and spinach. “[S]mall amounts from multiple sources can add up to dangerous levels. That’s why it’s important to limit exposure when you can”(Consumer Reports). 

Many people eat dark chocolate for the health benefits. Flavanols, which are antioxidants found in cocoa beans, can lower cholesterol, improve the function of blood vessels, and reduce inflammation. Dark chocolate is a healthier alternative to milk chocolate, with its lower levels of sugar. These health benefits must be balanced with the risks from lead and cadmium. At the same time, cocoa bean growers can lower lead levels of lead by 15 to 20 percent by reducing the time in which cocoa beans are on soil. Cadmium is more difficult to control due to being drawn through the plant’s roots to the beans. While there are genetically modified plants and ways to replace soil contaminated by cadmium, both methods are time-consuming and expensive. 

However, there is no need to cut dark chocolate out of one’s diet. Proposition 65’s regulations are among the most stringent in the world, and the FDA found that “the U.S. food supply is among the safest in the world…The presence of cadmium and lead in chocolate are well documented”(Today). The amount of lead and cadmium suggested by Proposition 65 are designed to ensure safety and are far lower than the amount of lead and cadmium that would pose a health risk. The best way to prevent lead and cadmium accumulation in the body is the FDA’s advice, “that consumers eat a variety of healthy foods for nutrition and food safety.”(Today). A varied diet, not relying on one type of food for nutrients is by far the healthiest way to maintain health.