Dark chocolate and heavy metals What latest study reveals?

Recent research has raised concerns about heavy metal contamination in cocoa products, including dark chocolate, following an extensive study by George Washington University and ConsumerLab.

A new study has found that while the levels of heavy metals in cocoa products are generally not alarming, they are worth noting for consumers, Caliber.Az reports citing the foreign media.

The eight-year research conducted by George Washington University and ConsumerLab, a health food and supplement testing company, revealed that some dark chocolates and cocoa products exceed California’s stringent regulations for lead and cadmium.

Leigh Frame, co-lead author of the study and executive director at George Washington University’s office of integrative medicine and health, emphasized that although the detected levels of lead were not concerning on their own, the cumulative effect of heavy metal exposure from various sources should be acknowledged. "Most people probably don’t have a clear understanding of their overall heavy metal exposure," Frame said.

The study does not suggest that people should stop consuming dark chocolate, which has been linked to potential health benefits such as reduced risk of heart disease and high blood pressure due to its flavonoid content. However, Frame cautioned that ongoing, small exposures to heavy metals, combined with other dietary sources, could contribute to higher blood lead levels over time. "We need to be aware of this, but I don’t want people to fear chocolate," she added. "It's a minor contributor to our overall diet."

The facts

ConsumerLab's study on cocoa products, selected based on a survey completed by thousands of respondents annually, has revealed noteworthy findings about lead and cadmium levels. The study involved ConsumerLab purchasing and funding tests of these products at two independent laboratories. The results were analyzed by researchers at George Washington University, who did not know the product brands during testing.

The study found that 43 per cent of the 72 cocoa products tested contained lead levels exceeding California’s maximum allowable daily dose of 0.5 micrograms. Additionally, 35 per cent of the products had cadmium levels above California's safety limits. However, 70 of the 72 products had lead levels below the Food and Drug Administration's threshold of 2.2 micrograms per day for children, which is almost ten times lower than the CDC’s benchmark for identifying high blood lead levels.

Some products exhibited significantly higher levels of lead, with one sample reaching 3.13 micrograms per serving, the highest recorded in the study. Despite these findings, the researchers suggest that the detected levels of heavy metals may not pose a significant risk when consumed in single servings. They chose California's strict regulations for analysis due to its conservative estimates, which are commonly used in similar studies.

The study, published in Frontiers in Nutrition, follows a 2022 Consumer Reports investigation and subsequent 2023 testing, both of which detected heavy metals in dark chocolate. An FDA spokesperson commented that, despite media attention, chocolate is considered a minor source of exposure to these contaminants internationally.

Jacob Hands, co-lead author of the study and a medical student at George Washington University School of Medicine and Health Sciences, is also a contract researcher for ConsumerLab.

Historically, cocoa has been valued for its medicinal properties, such as treating fatigue and improving digestion. Research indicates that flavonoids in cocoa may reduce the risk of heart disease, high blood pressure, and diabetes. Notably, darker chocolates, which contain higher cocoa levels, are richer in these beneficial flavonoids.

However, chronic exposure to heavy metals like lead and cadmium can pose health risks, including kidney dysfunction. Infants, young children, and pregnant individuals are particularly vulnerable, as early lead exposure can increase the risk of developmental issues such as learning disabilities and lower IQ.

In the US, lead exposure from food has significantly decreased, from 43 micrograms per day in 1980 to around 1 microgram per day in 2016, according to the FDA. Despite this progress, lead contamination in food products remains a concern. Recently, the FDA issued warnings about high lead levels in certain brands of cinnamon applesauce and ground cinnamon.

Leigh Frame, co-lead author of the study, reassures that children are less likely to be affected by dark chocolate due to their general aversion to it. Dark chocolate, with its higher cocoa content, may contain more heavy metals, but cocoa powders used in products like hot chocolate usually have less raw cocoa and therefore lower levels of these contaminants. “I don’t think we need to worry as much about kids,” Frame noted.