Researchers at the George Washington University (GW) in the US have found that lead and cadmium contaminate a substantial percentage of cocoa products in the country, in an extensive analysis conducted between 2014 and 2022. The study found that organic products were more likely to demonstrate a higher level of toxins.

The researchers tested 72 cocoa consumer products for lead, arsenic and cadmium in four cohorts over eight years, establishing thresholds of maximum permissible dose levels to examine the extent of contamination.

Dr. Leigh frame, executive director of the Office of Integrative Medicine and Health at GW, led the research with lead author Jacob Hands, a medical student researcher in the frame-Corr Lab at GW’s School of Medicine and Health Sciences.

Key findings
The findings reveal that among the products tested, 43% surpassed the maximum allowable dose level for lead, while 35% crossed the threshold for cadmium. None of the products appeared to go over the permissible levels for arsenic.

Products labeled as organic demonstrated higher levels of heavy metals, lead and cadmium than non-organic products.

The study, published in nclick="updateothersitehits('Articlepage','External','OtherSitelink','Cocoa contamination: US study finds lead and cadmium in many chocolate products','Cocoa contamination: US study finds lead and cadmium in many chocolate products','342415','https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1366231/full', 'article','Cocoa contamination: US study finds lead and cadmium in many chocolate products');return no_reload();">Frontiers in Nutrition, warns that consuming these products in single servings may not pose health risks. However, eating multiple servings each day, combined with foods that might be sources of heavy metals, could lead to exposure levels surpassing the maximum allowable dose levels.

The research notes that “the question of ‘hazard’ associated with consumer consumption of heavy metals contained in cocoa-containing products is complex.” Since no amount of lead consumption is deemed “safe,” the authors point out that lead exposure among vulnerable groups should be monitored.

The products analyzed in the study were either produced domestically or in Europe. Purchases were made from e-commerce portals such as Amazon and iHerb, physical supermarkets like GNC and Whole Foods, and direct buys from manufacturer or distributor websites.

Previous nclick="updateothersitehits('Articlepage','External','OtherSitelink','Cocoa contamination: US study finds lead and cadmium in many chocolate products','Cocoa contamination: US study finds lead and cadmium in many chocolate products','342415','https://ehp.niehs.nih.gov/doi/10.1289/ehp.113-a687', 'article','Cocoa contamination: US study finds lead and cadmium in many chocolate products');return no_reload();">research has shown that the presence of heavy metals in dark chocolate and other cocoa products can be because of “post-harvesting contamination.”

GW researchers also note that the proximity of cocoa farms and processing units, wher industrial activity can leave a heavy environmental footprint, is believed to contribute significantly to chocolate contamination. Therefore, more stringent quality control practices during harvesting and manufacturing can help mitigate the risk.

“Safe to eat”
The National Confectioners Association, a trade organization of chocolate, candy, gum and mint companies, has defended the products in response to the study.

“Chocolate and cocoa are safe to eat and can be enjoyed as treats as they have been for centuries. Food safety and product quality remain our highest priorities, and we remain dedicated to being transparent and socially responsible.”

The association adds that US consumers are aware that chocolate and candy are occasional treats and not “center-of-the-plate foods.” It cites Centers for Disease Control and Prevention data indicating that people in the US enjoy chocolate and candy two-three times per week, averaging 40 calories and about one teaspoon of added sugar per day.