Can dark chocolate's heavy metals harm your child's brain?

What's actually in it

Dark chocolate contains lead and cadmium that come from the soil where cacao grows and from the manufacturing process. The higher the cacao percentage, the more metals it contains. An 85% dark chocolate bar has more lead and cadmium than a milk chocolate bar.

Children's brains are still developing and are especially sensitive to heavy metals. Even small amounts can affect learning, attention, and behavior.

What the research says

A 2026 review in Food Chem Toxicol examined the evidence on heavy metals in dark chocolate and the risk to children's neurodevelopment.

Lead and cadmium levels in many dark chocolate products exceed California's Proposition 65 limits. While these limits are conservative, they exist because there's no truly safe level of lead exposure for children.

The review found that children who regularly ate dark chocolate could accumulate enough lead to measurably affect IQ and attention. The risk is higher for kids who eat dark chocolate daily as a "healthy snack."

For adults, the amounts are less concerning because larger body weight dilutes the dose. But for children, even a small square of high-percentage dark chocolate delivers a proportionally larger dose of metals per pound of body weight.