Why Study Heavy Metals in Chocolate?
Dark chocolate, long touted for its potential health benefits because of its high antioxidant content, has in recent years faced scrutiny because of reports of heavy metal contamination. Consumer media outlets and independent testing agencies, including Consumer Reports and As You Sow, have previously highlighted this issue.Given these concerns, Leigh Frame, director of integrative medicine at George Washington University and co-lead of the study, aimed to explore the significance of this contamination.
Study Design
The researchers analyzed popular cocoa-containing products—including Ghirardelli, Hu, Lily’s, 365 by Whole Foods Market, Nestlé, Now Real Food, Baker’s, and Good & Gather—from 2014 to 2022.- The U.S. Food and Drug Administration (FDA) established interim reference levels (IRLs) with the following allowable intake levels:
- Lead: 2.2 micrograms (mcg) per day for children younger than 7 years old
- Lead: 8.8 mcg per day for women of childbearing age
- California Proposition 65 (Prop 65) is a more stringent state-level regulation that established the following maximum allowable dose levels:
- Lead: 0.5 mcg per day
- Cadmium: 4.1 mcg per day
- Arsenic: 10 mcg per day
Study Findings
The new study’s findings paint a complex picture of heavy metal contamination in dark chocolate:- Lead: 43 percent of products tested exceeded Prop 65 limits, but 97.2 percent of the products fell below FDA IRL limits.
- Cadmium: 35 percent of products exceeded Prop 65 limits.
- Arsenic: No products exceeded Prop 65 limits.
Trade certifications (such as Fairtrade and non-GMO) did not significantly affect heavy metal levels. Organic-labeled products showed significantly higher concentrations of cadmium and lead. They were 280 percent more likely to exceed Prop 65’s cadmium limit and 14 percent more likely to exceed its lead limit.
“Our hypothesis was that organic products would be lower in heavy metals because they were not going to have fertilizers or pesticides used on them that were contaminated with heavy metals. But it’s exactly the opposite,” Frame said.
Why organic products had higher levels of heavy metals is unclear. Frame questioned whether fertilizers and pesticides may not be adding as many heavy metals to food as previously thought.
Health Concerns: Lead and Cadmium
There is no known safe level of lead in the blood because even low levels can produce toxic effects, according to a 2021 article in Toxics. The central nervous system is particularly vulnerable to lead, potentially resulting in cognitive decline, fine motor control impairment, and attention-related issues in both children and adults, according to the article.Frame and her research team question whether the proposed benefits of cocoa outweigh the possible risk of heavy metal exposure.
“It’s hard to say whether these benefits are really truly beneficial for the average human,” she said.
According to Frame, while dark chocolate has been associated with improved cardiovascular health, cognitive performance, and reduced chronic inflammation, these potential health benefits have been modest.
“As with anything, it has to do with what is the background diet,“ Frame said. ”So, you have someone that has a very low polyphenol, low flavonoid diet, and chocolate is one of their predominant sources. Then in terms of the flavonoids, it may be very beneficial. That’s why coffee is so beneficial for the average American because their diet is very low in polyphenols. And coffee is very rich in polyphenols and so it’s a really important source.”
Frame suggests that potential benefits from cocoa may be similar.
“If you have someone who already has a rich source of polyphenols in the diet, the contribution of chocolate is going to be pretty minimal,“ she said. ”And then that person is exposing themselves to more heavy metals from the chocolate without getting the health benefits.”
Moreover, the potential risks associated with heavy metal exposure have not been fully accounted for in previous studies promoting the health benefits of dark chocolate, according to Frame. She suggests a better approach is to look at the individual and ask whether that person is meeting his or her flavonoid levels and then use chocolate to increase those levels.
For those concerned that their love of dark chocolate could be at risk, it is also worth noting that any risk is a matter of moderation. The GWU study concludes that “if contaminated products as a whole are consumed in small amounts and infrequently by most, these contaminants may not be a public health concern (though, perhaps still an individual concern); in contrast, if many such products are consumed fairly regularly by the average consumer, the additive exposure may be a public health concern.”
Ghirardelli said that “food safety and high quality are paramount for Ghirardelli and the entire Lindt & Sprüngli Group,” and directed The Epoch Times to a statement issued by the National Confectioners Association in 2022 after an earlier report on heavy metals in chocolate.
That statement notes efforts that chocolate makers take to ensure the quality and safety of their products:
“An expert investigation conducted through our prior California Proposition 65 settlement concluded that cadmium and lead are present in cocoa and chocolate due to soil and that bean cleaning during processing cocoa beans reduces lead and cadmium in chocolate products,” that statement reads.
Hu also responded, noting the efforts that it takes to address any potential contaminants.
“In regard to both media articles that have been published, we confirm that we comply (by a very large margin) with all applicable standards, including those in the California State Consent judgment, which are far-stricter than both the FDA and European Regulations,“ the company stated. ”In addition, we have testing protocols in place to monitor the naturally-occurring trace amounts of heavy metals found in chocolate to ensure we are only bringing product to the market that is well below any applicable standard’s limit and is safe to consume.”
Where Are the Heavy Metals Coming From?
Cocoa trees can absorb heavy metals that naturally occur in the soil and heavy metals from environmental contamination. The main sources of heavy metal contamination in the soil are livestock manure, irrigation with wastewater or polluted water, application of sewage sludge, use of metallo-pesticides or herbicides, phosphate-based fertilizers, and atmospheric deposition, according to a 2019 review in Environment International.“We undervalue the soil as a source of heavy metals, particularly in certain regions,“ Frame said. ”There is a huge variation in regions. But, right now, when you buy a chocolate bar, you have no way of knowing where those beans came from because it’s not labeled.”
As the beans dry, this lead-containing dust can settle on and adhere to their surface. Unlike cadmium, which is thought to be absorbed into the beans through the plant’s root system, lead contamination may be largely a surface-level issue that occurs after the beans have been harvested, according to Consumer Reports.
Frame and her team are advocating enhanced surveillance of heavy metal contamination in cocoa products and suggest that better quality control practices during harvesting and manufacturing could help to mitigate the problem.
“Ideally they would test every batch,” she said.
For consumers, Frame envisions a voluntary labeling system that is simple to understand.
Implications and Takeaways
For most people, eating a single serving (one ounce) of dark chocolate is unlikely to pose a significant health risk, according to Frame.“The reason we recommend one ounce is because that quantity is often studied for health benefits and you have to imagine that the heavy metals in one ounce are not reaching a level that’s becoming problematic,” she said.
However, consuming multiple servings could lead to excessive exposure.
“It’s very easy to overconsume chocolate,“ she said. ”It’s something that can easily go from one to five or six servings. If people are having one ounce a day, maybe it’s okay. But if they’re having five servings a day and are getting astronomical levels of heavy metals, that’s a concern.”
The Bigger Picture: Cumulative Exposure
Dark chocolate is just one potential source of heavy metal exposure in our diets. According to a 2019 review in Environmental International, a growing body of research has identified concerning levels of heavy metals in various food crops, including:- Fruits
- Leafy vegetables—green cabbage, spinach, cauliflower, lettuce, kale
- Root vegetables—radish, turnip, carrot
- Wheat
- Rice
- Soybean
- Corn
- Garlic
What Can Consumers Do?
This new study serves as a reminder that even seemingly healthy foods can harbor possible hidden dangers. While dark chocolate has been associated with potential health benefits, it faces scrutiny for its heavy metal content. As consumers, we can balance the potential benefits against these risks. According to Frame, chocolate enthusiasts can still savor their favorite treat while reducing heavy metal exposure by considering these strategies:- Be aware that “organic” or other certifications do not necessarily mean a lower heavy metal content. In fact, organic products may have higher concentrations, according to the study.
- Enjoy dark chocolate in moderation as part of a balanced diet. Frame’s suggested serving size is no more than one ounce per day.
- Vary sources of dark chocolate and cocoa products.
- Alternate between dark and milk chocolate if you can tolerate lactose. While dark chocolate offers more antioxidants and less sugar, it may contain higher levels of heavy metals because of its higher content of cocoa solids (where heavy metals tend to accumulate). White chocolate has no cocoa solids, making it another good option.
- Locate specific cacao brands that regularly test for heavy metals using third-party laboratories and have shown lower contamination levels. Organizations such as Consumer Reports and As You Sow provide test results from common chocolate products. Although these results are snapshots in time, they may help to identify which products might be safer choices.
- Diversify your diet to help minimize the risk of excessive exposure to heavy metals from any single source.
- Be particularly cautious with cocoa products if you are pregnant, breastfeeding, or feeding young children.
The Epoch Times received statements from two companies mentioned in the report.
Ghirardelli provided the following statement:
Hu also responded with a statement:
“In regard to both media articles that have been published, we confirm that we comply (by a very large margin) with all applicable standards, including those in the California State Consent judgment, which are far-stricter than both the FDA and European Regulations. In addition, we have testing protocols in place to monitor the naturally-occurring trace amounts of heavy metals found in chocolate to ensure we are only bringing product to the market that is well below any applicable standard’s limit and is safe to consume. We have a more detailed response that is available to read on our website. Here is the link - https://hukitchen.com/pages/response.”
The 2022 statement issued by the National Confectioners Association notes efforts chocolate makers take to ensure the quality and safety of their products:
“An expert investigation conducted through our prior California Proposition 65 settlement concluded that cadmium and lead are present in cocoa and chocolate due to soil and that bean cleaning during processing cocoa beans reduces lead and cadmium in chocolate products,” that statement reads.
This story has also been updated to include comments from the National Confectioners Association.
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