Toxic Levels of Lead, Heavy Metals Found in Many Popular Dark Chocolate Products: Study

A recent study has found that dark chocolate and other cocoa products often contain toxic heavy metals, which could potentially lead to severe health issues when large quantities are consumed, including organ damage, neurological disorders and an increased risk of cancer.

In findings published in the current edition of the medical journal Frontiers in Nutrition, Jacob M. Hands and other researchers from George Washington University identified more than 70 dark chocolate and cocoa products sold in the U.S., which contained lead, cadmium and arsenic.

Although the concentrations were low, and unlikely to pose serious health risks when consumed in small amounts, the report raises concerns about the cumulative side effects from heavy metal exposure as a whole, and how much of these dark chocolate products can be consumed before posing a public health concern.

Heavy Metal Exposure Risks

Lead, cadmium and arsenic are toxic substances that are known to cause long-term side effects, particularly among vulnerable populations like children.

Lead exposure among children is known to cause permanent brain damage, cognitive impairment and physical disabilities. Even short-term exposure may result in symptoms like headaches and vomiting, while prolonged exposure can lead to more severe outcomes, such as muscular weakness and confusion.

Health experts stress that there is no safe level of lead exposure for children, as even minimal contact can increase the risk of serious or permanent injuries, or even death.

Cadmium is a naturally occurring metal found in the Earth’s crust that is used in various industrial applications, including batteries, pigments and coatings. It is highly toxic, particularly when inhaled or ingested, and can accumulate in the body, leading to kidney damage, bone fragility, respiratory issues and an increased risk of cancer.

Similarly, toxic metalloids like arsenic are used in industries such as pesticides and wood preservatives. Exposure to arsenic through ingestion or inhalation can cause acute poisoning, skin lesions, cardiovascular disease and significantly increase the risk of cancers, including those of the skin, lungs and bladder.

In recent years, there have been rising concerns about the side effects of heavy metal exposure among children, following the discovery that many popular baby foods and other products commonly consumed by young Americans contain toxic levels of the substances.

Toxic Metals Found in Chocolate Sold at Whole Foods, Amazon and GNC

In this new study, researchers examined approximately 72 dark chocolate products sold by several major retailers, including Whole Foods Market, Amazon and GNC, finding that 43% of the products tested exceeded California’s Prop 65 limits for lead, while 35% exceeded the oral ingestion limits for cadmium.

Nearly all products fell within the U.S. Food and Drug Administration (FDA) acceptable safe limits for lead, and the average levels of these metals were generally low, suggesting that heavy metal contamination in most chocolate products might not pose a significant risk when consumed in single servings.

“This indicates that heavy metal contamination—in more than half of products tested—may not pose any appreciable risk for the average person when consumed as a single serving; however, consuming some of the products tested, or more than one serving per day in combination with non-cocoa derived sources heavy metals, may add up to exposure that would exceed the Prop 65 [maximum allowable dose levels],” Hands said.

The FDA has set limits for heavy metals in chocolate and sugar-based candy, but only for children. In California, the threshold for heavy lead in food is 0.5 micrograms per day. Scientists in a study estimated the daily exposure based on suggested serving sizes on chocolate labels. They found that chocolate samples contained between 0 and 3.316 micrograms of lead per serving. Cadmium levels, which can be harmful in high amounts, ranged from 0.29 to 14.12 micrograms, with the safe limit being 4.1 micrograms per day.

The findings indicate that many products may have lead and cadmium levels that exceed strict regulatory limits, suggesting a need for closer monitoring.

Researchers determined that if people consume contaminated chocolate products only occasionally, the risk might be low, but regular consumption could pose a public health concern. The presence of high contamination levels and significant outliers highlights the need for more extensive testing of cocoa products, to improve quality control and address public health concerns, they concluded.