For years, dark chocolate has been touted as good for you in moderation.
Research has shown that there may be benefits for your heart, cholesterol levels and blood pressure.
All of that is still true, but a report published in December on the heavy metals in dark chocolate can leave a bad taste in the mouth.
Scientists from Consumer Reports, an independent non-profit organization based in the US, tested 28 dark chocolate bars for lead and cadmium. They found one or both in all candy bars, some of which are sold in Canada.
According to a Health Canada website on a review of food products other than chocolate, these heavy metals are among the “top human health concerns” and have been shown to have serious health effects after prolonged exposure.
Knowing this, the scientists used California’s maximum allowable dose (MADL) guidelines of 0.5 micrograms for lead and 4.1 micrograms for cadmium to determine the risk posed by the candy bars.
Part of the reason the Consumer Reports team looked into dark chocolate was its “health credentials,” they said.
“It’s considered a healthier snack. And that’s because the flavanols found in dark chocolate have been linked to increased blood flow, antioxidant activity, and anti-inflammatory activity. However, some of the products also contain heavy metals and to some extent this is alarming,” said James E. Rogers, director of food safety research and testing at Consumer Reports.
So what’s the risk?
If you look a little closer at the test results, they found that just one ounce — or about 28 grams — out of 23 of the candy bars tested would give you the daily amount of heavy metals.
Of all the chocolates tested, five of the brands significantly exceeded the maximum levels for lead and cadmium.
Finding metals in food is not unexpected, according to Health Canada, because these metals are found in the environment and can end up in processed foods as a result of the ingredients used in a product or during food production.
A spokesman for Health Canada said Monday that they have studied cadmium and lead in food sold in Canada and that chocolate contributes “only marginally” to the overall dietary exposure.
They emphasized in their emailed statement that “chocolate consumption by the Canadian population poses no health risk.”
An Ottawa-based researcher says it’s important to remember how much dark chocolate the average person would need to consume to reach risky levels of lead or cadmium.
“It’s a candy that you don’t eat like a kilogram of every day. As a person who eats a piece or two of dark chocolate every day, I’m not too concerned about that,” Yaxi Hu said. Assistant Professor in the Food Science Program in the Chemistry Department at Carleton University and Head of the University’s Food Analytical Chemistry and Technology Laboratory.
According to Rogers, the whole motivation for the test — and everything Consumer Reports tests — is so consumers can be informed and make the best choices when they’re looking for something to satisfy their sugar cravings.
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The health effects
Lead has no known benefit to the human body.
According to the Centers for Disease Control and Prevention (CDC), well-documented health effects include:
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Damage to the brain and nervous system
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Slowed growth and development
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learning and behavioral problems
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hearing and speech problems
Infants and children are particularly at greater risk of the long-term effects of lead on their health, according to the CDC.
Cadmium is known to be a carcinogen, and when eaten in large amounts it can irritate the stomach and cause vomiting and diarrhea, the CDC says.
Hu says it’s important for people to know about the health risks and heavy metal levels in food.
“We all know that there are heavy metals here and there, but we don’t often see exactly how they’re there,” said the Canadian researcher, who didn’t take part in the Consumer Reports test. Her research focuses on developing analytical methods to better detect food safety and adulteration issues.
“It definitely gives consumers more information when making food choices.”
In the United States, there are no federal limits on the amount of lead and cadmium that can be found in food. The California thresholds were used because they were considered by the scientists to be “the most protective available.”
In Canada, lead may not be added to any food sold here. However, it “is present in all foods, generally in very small amounts,” according to a Health Canada website. According to Health Canada, beverages (including beer, wine, coffee, and tea), grain-based foods, and vegetables have historically been the food groups that contributed most to dietary lead intake in Canadians.
A spokesman for Health Canada said that because the levels of cadmium and lead in chocolate products represent such a small percentage of the daily dietary intake, there was no need to set specific maximum levels for these two heavy metals.
How do the heavy metals get into chocolate?
The authors of a March 2022 report found that lead enters cocoa used to make dark chocolate after the cocoa beans are harvested.
The report was prepared as part of a dispute settlement over whether California law requires certain levels of lead and cadmium in chocolate to be a warning. The 2018 Settlement Agreement also established thresholds for lead and cadmium, above which warning labels on chocolate products are required.
Cadmium likely gets into dark chocolate products because the cocoa plants absorb the heavy metal from the soil, the researchers found.
In the chocolate industry it is known that concentrations of both heavy metals can be found in the bitter-tasting foods. But lately, more and more consumers are becoming aware of heavy metals in the product, said Michael Sacco, owner of Toronto-based chocolate maker ChocoSol.
“Canadians need to understand, like everything else, that procurement is so crucial,” he said.
“A grape grown in artificial chemical fertilizers is not the same as a grape grown on properly tended soil. Not all agricultural models are created equal.”
Sacco also says it’s important to put things in perspective.
“Cocoa will contain some cadmium, yes. But is the cadmium in the cocoa you eat in that dark chocolate any worse for you than the highly refined preservatives and hydrogenated oils and things like that? So it’s really important to somehow put things in perspective,” he said.
Can I still have dark chocolate?
Canadians are known to have a sweet tooth for chocolate, spending an average of $88 a year on candy bars. So the news could be heartbreaking for some chocolate lovers.
However, it’s important to remember that overall lead and cadmium levels in chocolate contribute modestly to overall dietary exposure, according to Health Canada.
Rogers says don’t panic as there are other chocolate options, with Consumer Reports scientists finding five “safer alternatives” to dark chocolate.
“Combine our research and information with other organizations that have tested dark chocolate and become an informed consumer and make wise choices,” he said.
