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Dark chocolate has long been thought to have health benefits. We’re told it can improve our mood, reduce inflammation, and even increase blood flow.
But some researchers are now warning about the heavy metals in our favorite dark chocolate bars.
Consumer Reports tested 28 dark chocolate bars, including Dove, Ghirardelli, Lindt and Hershey’s, for lead and cadmium. For 23 of those bars, just one ounce of chocolate violates California’s Maximum Allowable Levels (MADL) for lead or cadmium, which are 0.5 micrograms and 4.1 micrograms per day, respectively, the release said.
A typical chocolate bar ranges from 1.5 ounces to 3.5 ounces.
California Proposition 65 Limitations according to Consumer Reports, are among the most protective in the country. The US Food and Drug Administration offers more flexible recommendations for daily intake of lead: 2.2 mcg for children and 8.8 mcg for women of childbearing age.
As examples cited by Consumer Reports, Lindt’s Excellence Dark Chocolate 70% Cacao or Dove’s Promises Deeper Dark Chocolate 70% Cacao exceed acceptable levels of cadmium, while Godiva’s Signature Dark Chocolate 72% Herkshe Chocoledy Cacao exceeds acceptable levels. exceeds acceptable lead levels.
Trader Joe’s The Dark Chocolate Lover’s Chocolate 85% Cocoa had higher levels of lead and cadmium than California limits. Trader Joe’s did not immediately respond to a request for comment.
The National Confectioners Association, which represents chocolate makers including Hershey’s, Lindt and Godiva, reached a settlement in 2018 with As You Sow, a group that advocates for Proposition 65. The settlement has established concentration levels for both lead and cadmium that require warning labels if. exceeded. The association maintains that the industry has adhered to the levels set by the settlement.
“The products identified in this study meet strict quality and safety standards, and the levels provided by Consumer Reports testing are well below our local limits,” association spokesman Christopher Gindlesperger said. “Food safety and product quality remain our highest priorities, and we remain committed to being transparent and socially responsible.”
Andrew Stolbach, a toxicologist at Johns Hopkins Medicine, told NPR that the MADLs would be “very conservative” to account for people at higher risk because of their age and other medical conditions. When chocolate is consumed in moderation, He says lead and cadmium levels are nothing to worry about.
“Safety levels for lead and cadmium are very protective, and exceeding them by modest amounts is not a concern,” he said. “If you make sure the rest of your diet is good and adequate in calcium and iron, you’re protecting yourself more by preventing some of the lead and cadmium in your diet.”
Essential cadmium exposure can cause lung cancer, birth defects, and other reproductive harm while significant; Lead exposure can slow growth and development in children and damage the brain and nervous system.
But consumer reports Tests proved it was also possible to maintain low levels of heavy metals for dark chocolate bars, as five of the 28 bars had lead and cadmium levels that met California limits.
Between the Confectioners Association and As You Sow, an organization that promotes corporate social responsibility, it took both parties a multi-year study to understand the root causes of heavy metals in chocolate and strategies to reduce those levels. A report discussing the results of the three-year study was released in August.
The researchers found that the cadmium in cocoa beans comes naturally from the soil and is transported directly to the beans by the cocoa tree. Lead contamination occurs after harvest, when wet cocoa beans are exposed to soil and dust during the drying, fermentation and transportation stages.
“Industry needs to educate farmers on the value of implementing better farming practices to reduce wet cocoa bean contact with the soil during fermentation and drying,” wrote Timothy Ahn, co-author of the report, who leads food safety at Lloyd’s Register. “Drying of wet beans in direct contact with soil, road surfaces and concrete yards should be discontinued as a farmer-controlled Pb (lead) reduction activity.”
Wet contact of cocoa with soil and dust can reduce the lead content of chocolate by between 10% and more than 25%, according to co-author and toxicologist Michael DiBartolomeis.
Other ways to reduce heavy metal levels include mixing cocoa beans with high cadmium levels with those with low levels, identifying areas of contamination and conducting stronger testing, according to the As You Sow report.