Is Your Valentine’s Day Chocolate Contaminated With Toxic Metal?

A new study finds unsafe levels of lead and cadmium in some popular candy.
(Photo: François Lenoir/Reuters)
Feb 12, 2015· 2 MIN READ
Melanie Haiken is a San Francisco Bay Area–based health, science, and travel writer who contributes regularly to Forbes.com and numerous national magazines.

That shiny Valentine’s Day box of chocolates might come with a toxic dose of heavy metals, according to consumer group As You Sow, which on Wednesday accused some of the country’s top chocolatiers of violating California’s Proposition 65 toxic warning law.

Using an independent lab, which conducted three rounds of tests, As You Sow found that 26 of 42 chocolate varieties evaluated contained levels of lead or cadmium high enough to be considered unsafe by state standards. Serving-size samples contained lead levels as high as 5.9 percent above the safe limit and cadmium levels as much as 8.2 times above the limit.

This is the second salvo in As You Sow’s chocolate war. On Wednesday, the watchdog filed notice against Hershey’s, Mars, and See’s Candies. The move follows a filing last summer that named 13 other chocolate makers, including Godiva, Lindt, and Ghirardelli, and documented toxic levels of cadmium and lead in some of their sweets.

Prop. 65, a ballot initiative approved by California voters in 1986, requires companies to disclose the presence of chemicals in their products that are known to cause cancer, birth defects, or reproductive problems.

“We want consumers to be aware there are toxic heavy metals in chocolate so they can make better choices,” said Eleanne van Vliet, As You Sow’s toxic chemical research director. “Even tiny amounts can be dangerous because they accumulate in the body over time.”

It’s not just the big, conventional candy companies that are accused of making heavy metal–tainted chocolates: Whole Foods, Earth Circle Organics, and Trader Joe’s also made As You Sow’s list.

How the metals are getting into the cacao is complicated, said van Vliet. Possible culprits include industrial pollution, mining, and the manufacturing process.

In response to As You Sow’s report, the National Confectioners’ Association, an industry trade group, said that because lead and cadmium are elements that occur naturally in the Earth’s crust, traces of the heavy metals are unavoidable in many foods. While cocoa beans, like many other plants, may contain small amounts of heavy metals, chocolate and cocoa are safe to eat, the organization said.

Lead is a neurotoxin, posing extreme risk to children’s brain development, among other things. Experts consider lead so dangerous that there is no safe limit for children. According to the Centers for Disease Control and Prevention, even very low lead levels have been shown to decrease IQ and increase the risk of ADHD and learning problems.

The health dangers of cadmium haven’t received as much attention, but recently this heavy metal hit the headlines as well; it was implicated in research showing that it appears to accelerate cell aging.

Studying blood and urine samples from 6,700 people, researchers at George Washington University discovered that people with the highest levels of cadmium in their blood and urine had shorter telomeres, the tips of chromosomes considered to be markers of life span. The study, published in the American Journal of Epidemiology, presented strong evidence that exposure to cadmium causes cells to age prematurely.

Cadmium is also known to cause kidney and liver damage. Toxicology studies have shown the metal can accumulate in bones, weakening them.

As with lead, cadmium is even more dangerous for kids. Researchers from Harvard University recently demonstrated a link between cadmium exposure and a host of learning disabilities.

All of the chocolate found to contain heavy metals falls into the category of dark chocolate, some containing as much as 85 percent cacao. The samples of milk chocolate tested were found to be safe. Dark chocolate tends to have the heaviest concentration of heavy metals because the cacao itself is more concentrated.

Of course, this is ironic for health nuts who have happily cultivated a dark chocolate habit, spurred by news of its high flavonoid content and many antioxidant health benefits.

As You Sow hopes companies will begin testing chocolate to be sure it’s heavy metal–free.

“Consumers shouldn’t have to be chemists to know what lurks in their chocolate bar,” said van Vliet. “We want chocolate manufacturers and their suppliers to work together to identify the sources of these metals and solve this problem.”