A study by Consumer Reports reveals that about one-third of chocolates, including dark chocolates and chocolate products from major brands, contain concerning levels of heavy metals like lead and cadmium.
Prolonged exposure to heavy metals can lead to health issues, such as high blood pressure, developmental delays, brittle bones, and potential risks of infertility and cancer.
About a third of chocolates contain heavy metals like lead and cadmium, according to a new study from Consumer Reports (CR). Researchers tested nearly 50 types of chocolate and discovered that, in general, dark chocolates had higher levels of heavy metals compared to milk chocolates. Items with higher cocoa levels also had more heavy metals, however, every single product tested — including chocolate chips and hot chocolate mixes — contained some amount of lead or cadmium.
Heavy metals occur naturally in soil and can easily be deposited into plants and wind up into our foods. “If consumers eat large amounts of these contaminated foods or consume heavy metals from other sources — like drinking water — on a frequent basis, they may develop unwanted health effects like high blood pressure, developmental delays, and brittle bones,” Kelly Johnson-Arbor, MD, a medical toxicology physician from Washington, DC, told MDLinx.
The researchers say we don’t need to give up chocolate for good. But it’s worth being aware of how chocolates may contribute to your overall heavy metal exposure, and certain groups, such as children and pregnant people, may want to limit how much chocolate they eat and choose safer options.
These chocolate items contained unsafe levels of heavy metals
To understand how many heavy metals are in store-bought chocolates, the researchers tested 48 different chocolate products across seven categories—cocoa powder, chocolate chips, milk chocolate bars, and mixes for brownies, chocolate cake, and hot chocolate. Some were made by some of the biggest chocolate manufacturers, including Hershey’s and Nestlé, and others were produced by major retailers like Costco, Target, and Trader Joe’s.
They took three samples of each product and measured them for lead, cadmium, mercury, and arsenic. They then compared the levels detected to California’s standard maximum allowable dose levels for lead, which is 0.5 mcg per day, and cadmium, 4.1 mcg per day in food. The research team used the standards established in California because there are no federal limits regarding how much lead and cadmium most foods can contain.
The researchers discovered sixteen products had concerningly high levels of heavy metals, and a few had up to two times the amount deemed safe. Of the seven dark chocolate bars tested, five (71%) contained excess levels of lead or cadmium. Perugina Premium Dark Chocolate bars had the highest amount of heavy metals, followed by Evolved Signature Dark 72% Cacao Chocolate Bar and Sam’s Choice Dark Chocolate 72% Cocoa.
Milk chocolate, in general, contained far less lead and cadmium. “I am not surprised that milk chocolate contained lower levels of heavy metals because the milk and other ingredients would dilute the contaminants in the chocolate,” says Luz Claudio, PhD, a professor of environmental medicine and public health at the Icahn School of Medicine at Mount Sinai.
Of the 12 chocolate chip products tested, only two — Hu Dark Chocolate Gems and Good & Gather (Target) Semi-Sweet Mini Chocolate Chips — contained high levels of lead when consumed in large amounts. Healthy, safe options included 365 Whole Foods Market Semi-Sweet Chocolate Baking Chips, Kirkland Signature Semi-Sweet Chocolate Chips, and Nestlé Toll House Semi-Sweet Morsels. In regards to cocoa powder, only one product — a tablespoon of Hershey’s Cocoa Naturally Unsweetened 100% Cacao — exceeded standard lead levels.
Four of the six hot chocolate mixes tested had high levels of lead. They included Walmart’s Great Value Milk Chocolate Flavor Hot Cocoa Mix and Trader Joe’s and Nestlé mixes. Most brownie and cake mixes didn’t contain concerning amounts of heavy metals. Bob’s Red Mill Gluten Free Chocolate Cake Mix, however, exceeded CR’s lead limits..
“This was a well-conducted study that showed that many chocolates may contain toxic heavy metals,” says Dr. Claudio.
The health concerns of consuming foods with heavy metals
Over time, any amount of heavy metals can be harmful to human health, the researchers say. Adults who are exposed to high amounts of lead, for example, may develop headaches, abdominal pain, and high blood pressure. Some evidence has linked heavy metal exposure to infertility in women.
It’s also long been known that lead exposure can lead to brain damage. “Children, whose brains and nervous systems are still developing, are highly susceptible to the harmful effects of lead on the central nervous system,” says Dr. Johnson-Arbor. Low levels of lead can cause developmental delays, and severe lead poisoning can trigger confusion, seizures, and anemia, Dr. Johnson-Arbor added.
Long-term exposure to cadmium, on the other hand, can contribute to kidney disease, brittle bones, and, in some cases, an increased risk of certain cancers. It may also lead to cardiovascular disease. Cadmium is classified as a probable carcinogen.
How to have safer chocolates
According to the Food and Drug Administration (FDA), heavy metals in chocolates have been a concern for years. However, it’s believed that, compared to other foods, it is a minor source of heavy metal exposure.
“Previous research has shown that heavy metals like lead and cadmium can be present in many plant-based foods that we consume on a daily basis, such as fruits, vegetables, and rice,” says Dr. Johnson-Arbor. These foods get contaminated with heavy metals through the soil during the growth and harvesting processes. “Cocoa trees may absorb them and concentrate it in the fruit, or there can be contamination at other points in the production process,” says Dr. Claudio. The researchers say the findings reveal that some chocolate manufacturers are “doing a better job of keeping metals out of their products than others.”
For most adults, “the occasional consumption of dark chocolate is unlikely to result in any adverse health consequences related to heavy metal exposure,” Dr. Johnson-Arbor says. Those who are concerned about heavy metal exposure, including those with a heightened risk, may want to opt for milk chocolate over dark chocolate and other items high in cocoa. “Children and pregnant women should really consider reducing their consumption, especially of dark chocolate,” says Dr. Claudio.
Identifying which chocolates contain concerning amounts of heavy metals can be difficult. Even when products are tested, they may not reflect the amount of heavy metals in each serving, Dr. Johnson-Arbor noted. The safest bet: “Consume chocolate on an intermittent basis,” she says. Dr. Claudio echoed the advice. “Based on this article, I think it is a good idea to consume chocolate in moderation,” she said.
When in doubt, people can check in with a healthcare provider, such as their primary care doctor, if they are concerned about consuming heavy metals. “If you have questions about whether you or a loved one have been exposed to lead, talk to your doctor about getting a simple blood test to detect the presence of lead in the body,” Dr. Johnson-Arbor said.