PHILADELPHIA (CBS) — Long considered healthier than other sweet treats, some types of dark chocolate contain potentially dangerous amounts of heavy metals, according to research released Thursday by Consumer Reports.
Scientists at the nonprofit recently measured the amount of heavy metals in 28 popular brands of dark chocolate bars and found cadmium and lead in all of them. For 23 of the bars, consuming just an ounce a day would put an adult above levels for at least one of the metals that could be harmful, CR said. Five of the bars were above those levels for both cadmium and lead.
Long-term exposure to even small amounts of heavy metals can lead to a slew of health problems, including developmental problems and brain development in young children, experts say.
“But there are risks for people of any age,” Tunde Akinleye, the CR food safety researcher who led the tests, said in a statement. Frequent lead exposure in adults can lead to nervous system problems, hypertension, immune system suppression, kidney damage and reproductive problems, he noted.
While most of the chocolate bars tested contained lead, cadmium or both, five had relatively low levels of both metals, CR found.
“That shows that it’s possible for companies to make products with fewer heavy metals — and for consumers to find safer products that they enjoy,” Akinleye said.
In determining the risks for the chocolate tested, CR used California’s maximum allowable dose level of 0.5 micrograms for lead and 4.1 micrograms for cadmium, as there are no federal limits.
CR found that an ounce of Hershey’s Special Dark Mildly Sweet Chocolate contained 265% more lead than what California allows, and Trader Joe’s Dark Chocolate 72% Cacao with 192% more.
Trader Joe’s did not immediately respond to a request for comment.
A Hershey’s spokesperson referred to the National Confectioners Association for comment. In an emailed statement, the trade group objected to CR’s use of levels set by California, noting that the state does not set federal food safety standards.
“The products featured in this study meet strict quality and safety requirements,” a spokesperson for the group said in an email to CBS MoneyWatch. “Food safety and product quality remain our highest priorities and we remain committed to being transparent and socially responsible.”
The confectioners’ association released research in August showing how to reduce lead and cadmium in chocolate, including allowing cocoa farmers to plant new trees.
According to CR’s findings, the safer choices are:
- Mast Organic Dark Chocolate 80% Cocoa. CR found that an ounce contained 14% less lead and 40% less cadmium than California’s permissible limits.
- Taza Chocolate Organic Deliciously Dark Chocolate 70% Cocoa contained 33% less lead and 74% less cadmium.
- Ghirardelli Intense Dark Chocolate 86% Cacao contained 36% less lead and 39% less cadmium.
- Ghirardelli Intense Dark Chocolate Twilight Delight. Lead was 61% below the allowable level and cadmium 96% below the allowable limit.
- Valrhona Abinao Dark Chocolate 85% Cocoa. Lead 63% and cadmium 73% lower.