Most of us can agree that chocolate is not only a tasty treat, but also serves as a comfort food. Since numerous studies have suggested that eating dark chocolate has health benefits, such as having a large supply of antioxidants and reducing the risk of heart disease, people often see dark chocolate as a healthier alternative to milk chocolate. However, a recent study has found that many dark chocolate bars contain two heavy metals, cadmium and lead, that can lead to numerous health problems in children and adults. 

Consumer Reports scientists tested 28 dark chocolate bars for lead and cadmium, including dark chocolate bars from Ghiradelli, Lindt, Dove, Godiva, and Trader Joe’s. Lead and cadmium were detected in all 28 dark chocolate bars, and for 23 of the dark chocolate bars, eating just one ounce would lead to too much intake of one of these heavy metals. Five of the dark chocolate bars were even found to contain unsafe levels of both lead and cadmium. 

Frequent, long-term exposure to high levels of lead and cadmium can lead to numerous health problems. Long-term exposure to high levels of lead and cadmium can especially pose threats to young children and pregnant women because these metals can cause developmental problems, affect brain development, and lead to lower IQ. Frequent exposure to these heavy metals can also lead to nervous system problems, hypertension, immune system suppression, kidney damage, and reproductive issues (Loria). 

However, while most of the dark chocolate bars had concerning levels of lead, cadmium, or both, five of the dark chocolate bars had relatively low levels of both heavy metals. These safer choices include Ghirardelli Intense Dark Chocolate (86% Cacao), Ghirardelli Intense Dark Chocolate Twilight Delight (72% Cacao), Mast Organic Dark Chocolate (80% Cocoa), Taza Chocolate Organic Deliciously Dark Chocolate (70% Cacao), and Valrhona Abinao Dark Chocolate (85% Cacao). 

Dark chocolate bars that are high in cadmium include Lindt Excellence Dark Chocolate (70% Cocoa), Dove Promises Deeper Dark Chocolate (70% Cacao), and Beyond Good Organic Pure Dark Chocolate (80% Cocoa). Dark chocolate bars that are high in lead include Trader Joe’s Dark Chocolate (72% Cacao), Hershey’s Special Dark Mildly Sweet Chocolate, Chocolove Extreme Dark Chocolate (88% Cocoa), and Lindt Excellence Dark Chocolate (85% Cocoa). Dark chocolate bars that are high in both lead and cadmium include Trader Joe’s The Dark Chocolate Lover’s Chocolate (85% Cacao), Theo Organic Extra Dark Pure Dark Chocolate (85% Cocoa), and Green & Black’s Organic Dark Chocolate (70% Cacao) (Truffaut-Wong). 

While you do not need to avoid dark chocolate completely, you may want to consider choosing your dark chocolates wisely. You want to choose the dark chocolates with the lowest levels of heavy metals and lower cacao percentages, since studies have suggested that cadmium levels tend to increase with the percentage of cacao. Overall, while eating dark chocolate once in a while will likely not cause any harm, you want to be careful about what kind of dark chocolate you are frequently consuming.