Not So Sweet

Lead And Cadmium Are Regulars In Dark Chocolate. Here's How To Avoid Them.

There's a dark side to dark chocolate.

Originally Published: 
A toddler eating a dark chocolate bar.
Cecile Lavabre/Getty

No matter how well you free chocolates from their aluminum wrappers, there’s a good chance you’re still ingesting some metal. Not because any of the aluminum has stuck around, but because research has shown that cadmium and lead — two heavy metals connected to a bevy of health problems, especially for growing children — are common in dark chocolate.

A recent Consumer Reports study found that each of 28 different popular dark chocolate bars tested contained cadmium and lead. Five of the bars contained more than an ounce of the elements, which is over the level that public health officials say may be harmful to adults.

Although this may be alarming to people with a sweet tooth, it’s not a new development. A 2005 study published in the journal Environmental Health Perspectives took a close look at the origins of lead contamination in cocoa products. According to the study, “lead contamination of candies has been recognized as a problem since 1820, when a British study found the poison widespread in London confectionery products.”

A 2022 report from the environmental and social corporate advocacy group As You Sow found that cocoa takes on lead after beans are harvested. Traces of the metal were found on the outer shell of cocoa beans, and lead-filled dust was kicked up as the beans were processed. That dust then settled onto the naked beans, which gave lead a vehicle into the cocoa supply.

Cadmium enters cocoa beans as they grow on trees in a similar fashion to how other heavy metals contaminate foods. As plants take up cadmium from the soil, it accumulates in the food products the plant produces, providing the metal entry into the dark chocolate supply.

So how bad are lead and cadmium for you? According to Consumer Reports, “consistent, long-term exposure to even small amounts of heavy metals can lead to a variety of health problems. The danger is greatest for pregnant people and young children because the metals can cause developmental problems, affect brain development, and lead to lower IQ.”

The chocolate industry bears responsibility for lowering the amount of heavy metals in their products. The As You Sow report presented five high-confidence solutions to the heavy metal problem that include cleaning and winnowing quality assurance practices for lead contamination and using soil amendments to increase soil pH, which has been shown to prevent the uptake of lead into vegetables.

Luckily for consumers looking to limit their exposure to heavy metals, there are mitigation steps that don’t require giving up chocolate altogether. Mixing in milk chocolate helps because it contains a lower cocoa concentration than dark varieties. And Consumer Reports was able to identify a handful of dark chocolates that contain relatively low levels of both lead and cadmium.

Some safer chocolate brands, per the Consumer Reports investigation, include certain bars of Mast, Taza, Ghirardelli, and Valhrona. The brands that were high in cadmium include Beyond Good bars, Equal Exchange bars, and more. As for lead, Tony’s Chocolonely Dark Chocolate was found to be high in the heavy metal, as was a Godiva bar and a bar from Chocolove. And then there were a handful of brands high in both cadmium and lead. For the full list, go to Consumer Reports.

It’s all a bit of a buzzkill for people who enjoy dark chocolate and thought it a healthier sweet treat with antioxidants, fiber, and a relatively low sugar content. But between industry reforms and conscious consumption, it’s still possible to enjoy dabbling in the delicious dark arts.

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