Dark chocolate is widely considered healthy, but testing has found contaminants in popular brands. Consumer Reports identified both cadmium and lead in chocolate brands like Trader Joe’s and Hu. Exposure is linked to serious health issues over time. Experts say awareness and moderation are key. Loading Something is loading. Thanks for signing up! Access your favorite topics in a personalized feed while you’re on the go. Downloading the app Dangerous heavy metals, including lead, may be lurking in your favorite dark chocolate brands, according to new test results released by Consumer Reports. The consumer advocacy nonprofit tested 28 different dark chocolate bars from popular brands. They found that all but five of them contained high enough levels of contaminants that eating an ounce per day could put an adult over the levels typically considered safe. Chocolate from brands including Tony’s, Lindt, Hershey’s, and Hu were found to contain comparatively high levels of lead. Exposure to lead is linked to cognitive impairment, particularly in children, since it can lead to developmental issues and lower IQ. It can also cause reproductive problems in adults, as well as high blood pressure and neurological issues, according to the Mayo Clinic. High levels of cadmium were detected in Lindt, Dove, and Beyond Good products, among others. The mineral is considered cancer-causing and exposure over time is linked to kidney disease and fragile bones, according to the CDC. One Trader Joe’s bar was found to contain high levels of both lead and cadmium. Dark chocolate tends to be higher in heavy metals than milk chocolate because it contains more cacao, the bean used to make chocolate, which can be contaminated either from the soil its grown in, or after the beans are picked, researchers told Consumer Reports. The levels found in the testing don’t violate any laws, according to Consumer Reports, since there are no federal limits for lead and cadmium in most foods. But a major risk of heavy metals is that they can build up in the body over time, causing health issues as repeated tiny doses add up, according to the Cleveland Clinic. As a result, it’s worth being aware of the risk, and there may be ways to reduce your exposure by opting for products with lower levels, like some of the chocolate bars tested, according to the food safety researchers at Consumer Reports. “That shows it’s possible for companies to make products with lower amounts of heavy metals—and for consumers to find safer products that they enjoy,” said Tunde Akinleye, the Consumer Reports food safety researcher who led the testing project. Contacted for comment by Insider, referred to a statement by the National Confectioners Association, which cites a settlement in California related to contamination concerns. “The products cited in this study are in compliance with strict quality and safety requirements, and the levels provided to us by Consumer Reports testing are well under the limits established by our settlement,” the statement reads in part. “Food safety and product quality remain our highest priorities and we remain dedicated to being transparent and socially responsible.” Dark chocolate is often considered a healthier choice, but steer clear of contaminantsDespite concern about contamination, there’s good reason to enjoy dark chocolate occasionally. Evidence suggests dark chocolate is hearty-healthy, helping to lower cholesterol and blood pressure thanks to beneficial plant-based compounds called flavonoids. In contrast, milk chocolate has fewer flavonoids, and more additives such as sugar. The tradeoff, however, is that the nutrient-rich cacao can be the source of the contaminants found by Consumer Reports. Some researchers are looking to infuse the benefits of dark chocolate into sweeter milk chocolate varieties. For now, your best bet may be moderation, according to the Consumer Reports researcher. One serving of dark chocolate is about an ounce, or around 30 grams. “Having a serving a few days a week, especially with a product that has lower levels, means you can eat dark chocolate without worrying unduly,” Akinleye said.