You may have heard that researchers recently found that some dark chocolates contain lead and cadmium. In this article I summarize the findings and what this means for consumers, i.e. anyone who loves to eat chocolate!
Research About Heavy Metals in Dark Chocolates
Consumer Reports recently measured the amount of lead and cadmium present in 28 dark chocolate bars. Their article along with their results can be found here1.
For anyone not familiar with Consumer Reports, the group describes themselves as an “independent, nonprofit member organization that works side by side with consumers for truth, transparency, and fairness in the marketplace.2“
The organization chose to research dark chocolate, which contains more cocoa solids than milk chocolate. Therefore, dark chocolates likely have greater potential for containing higher levels of lead and cadmium when compared to milk chocolate.
Why Do Dark Chocolates Have Lead and Cadmium in Them?
Chocolate is made from cocoa beans, and most of the lead found in cocoa beans is due to exposure to lead after the beans are harvested. Specifically, it is when the beans are fermented and dried that they come into contact with lead. These two processes are often completed outside in the elements alongside roads, concrete patios, on top of tables and also directly on the ground. As lead is found in the air, water and soil around us, you can see how the beans could be exposed to lead.3
Cocoa bean exposure to cadmium occurs while growing the beans; if the soil has cadmium then the plant will absorb it. The amount of cadmium in soil differs by location. Additionally, the genetic make up of the cocoa bean tree can also effect how much cadmium is absorbed by the plant3.
What Makes Lead Dangerous?
This heavy metal is naturally found in the air, soil and water. It is also found in paints, food and drink containers, cosmetics and plumbing materials. Lead can also be present in foods due to plant absorption from the soil it is grown in. Animals can also be exposed to lead from their feed.
Lead can negatively effect the health of both children and adults, but is most detrimental to children that are 6 years old and younger as their bodies absorb more lead than adults do. Lead can cause learning and behavior problems, hyperactivity, lower IQ, slowed growth, anemia and hearing problems in children. In rare cases it can also cause seizures, coma and death if ingested.
Just like calcium, lead is stored in our bones over time. During pregnancy, lead stored in bones can be passed onto the developing baby, causing risks for the child and the pregnancy. These risks include miscarriage, preterm delivery, a low weight baby, negative effects on the baby’s nervous system, kidneys and brain, and increased risk of learning and/or behavioral problems.
In adults chronic lead exposure can cause cognitive decline, high blood pressure, other heart health issues, kidney issues and also issues with fertility and reproductive health for both men and women.
What Makes Cadmium Dangerous?
Cadmium is also naturally found in water, air and soil. People can be exposed to it through their food and water. Cadmium is also found in cigarettes and nickel-cadmium batteries. People that work with cadmium in their work place are also at risk for exposure.
The main health concern with being exposed to cadmium is the increased risk of cancers. This includes lung cancer, cancer of the prostate, kidneys, pancreas, bladder and also breast cancer.
What are the Recommended Limits on Exposure to Lead and Cadmium?
When Consumer Reports did their study they compared the lead and cadmium content of different dark chocolates to California’s maximum allowable dose level (MADL). It is notable that the MADL calls for stricter allowable levels of the heavy metals than the FDA does for lead. The MADL is also more strict on what is allowed for cadmium compared to WHO (the World Health Organization). Consumer Reports stated that they used the MADL as they believe it is the most protective for consumers. Below, I include the recommended limits from the MADL and also from the FDA and WHO so you can see the differences in recommendations.
Maximum daily intake of lead
It is not possible to completely prevent grown food from being exposed to lead, or to remove all lead from food. However, the amount of lead in our food can be decreased and exposure to lead must be prevented as much as possible.
California’s maximum allowable dose level (MADL) of lead is 0.5 mcg/day.
The FDA has defined the maximum amount of lead intake, or the interim reference level (IRL), to be 2.2 mcg per day for children and 8.8 mcg per day for women of child bearing age.
Maximum daily intake of cadmium
Similarly to lead, cadmium is found in soil, air and water.
The MADL for cadmium is set at 4.1 mcg/day.
According to WHO, cadmium exposure is tolerable up to 7 mcg/kg body weight per week.
What Were the Outcomes of the Study?
Consumer Reports looked at how much lead and cadmium were present in 1 oz of each dark chocolate sample.
To see all of the results, check out Consumer Reports’ article. You can scroll down to their visual guide, which I find to be very helpful.
Here I will highlight some of the findings I think are most interesting.
Dark Chocolates With High Levels of Lead
Out of 28 dark chocolate bars there were ten that were high in lead. The four chocolates that had the most lead include Hershey’s special dark mildly sweet chocolate, Chocolove extreme dark chocolate 88% cocoa, Hu organic simple dark chocolate 70% cocoa, and Trader Joe’s dark chocolate with 72% cacao. Check out the report to view all dark chocolates that contained high levels of lead.
Dark Chocolates with High Levels of Cadmium
There were eight dark chocolate bars that were high in cadmium. The four chocolates that had the most cadmium include Scharffen Berger extra dark chocolate 82% cacao, Alter Eco organic dark chocolate classic blackout 85% cacao, Pascha organic very dark dark chocolate 85% cacao, and Dove promises deeper dark chocolate 70% cacao. View the report to view all dark chocolates that had high levels of cadmium.
Dark chocolates with high levels of lead AND cadmium
In this study there were 5 dark chocolates that had high levels of both lead and cadmium. This includes Theo organic pure dark 70% cocoa, Trader Joe’s the dark chocolate lover’s chocolate 85% cacao, Theo organic extra dark pure dark chocolate 85% cocoa, Lily’s extremely dark chocolate 85% cocoa, and Green & Black’s organic dark chocolate 70% cacao.
Dark chocolates that were within the recommended limits
From the 28 dark chocolate bars that were tested, five were within recommended limits for both lead and cadmium. This includes Mast organic dark chocolate 70% cocoa, Taza chocolate organic deliciously dark chocolate 70% cacao, Ghirardelli intense dark chocolate 86% cacao, Ghirardelli intense dark chocolate twilight delight 72% cacao, and Valrhona abinao dark chocolate 85% cacao.
What can we do?
Choose Your chocolate carefully
For those of us who love eating dark chocolate, I believe the best thing we can do is to choose dark chocolates that contain the lowest and most acceptable amounts of lead and cadmium. Reports such as the one Consumer Reports provided are helpful; consumers are able to make the best decisions for their own health when they have the information in their hands.
Sign a petition
Consumer Reports has started a petition. It will go to the companies that make chocolates and will encourage them to reduce heavy metals in their chocolates. Click here if you are interested in participating.
What can Companies do?
I am hopeful that companies will choose to improve their practices so that their products contain less lead and cadmium. Among many options, below are some examples of what the Expert Investigation Related to Cocoa and Chocolate Products: Final Report suggests3:
- Companies educated cocoa bean suppliers on how to reduce lead and cadmium contamination after harvesting cocoa beans
- Companies purchase cocoa beans that contain less lead and cadmium
- Companies test surfaces of cocoa beans before purchasing
- Identify genotypes of cocoa bean plants that absorb less cadmium from the soil
- Offer incentives and provide funding for growers
Upon making improvements and lowering lead and cadmium content in their dark chocolates, I’d like to see these companies show proof of decreased heavy metals in their chocolates through a third party tester.
Other Thoughts
I would be interested to see how the dark chocolates’ lead and cadmium content compared to the FDA and WHO recommendations. I do think it is best to limit these heavy metals as much as possible, so I understand why Consumer Reports used the MADL (maximum allowable dose level) as a reference value. if the outcomes were compared to the less strict guidelines provided by the FDA and WHO, would the outcomes be more agreeable?
It would also be helpful to know the heavy metal content for other chocolates. There are so many more companies and different brands that sell dark chocolates. I would also like to see how other chocolate products are effected by heavy metals, including milk chocolates, cocoa powders, etc.
Noted References
- Lead and Cadmium Could be in Your Dark Chocolate. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/
- Our Mission. https://www.consumerreports.org/cro/about-us/what-we-do/index.htm
- Expert Investigation Related to Cocoa and Chocolate Products: Final Report https://candyusa.com/wordpress/wp-content/uploads/2022/08/Prop65-Settlement-Final-Report-FULL-TEXT-update.pdf
Other References
Learn about lead. https://www.epa.gov/lead/learn-about-lead
Lead and Lead compounds. https://oehha.ca.gov/proposition-65/chemicals/lead-and-lead-compounds
Cadmium. https://oehha.ca.gov/proposition-65/chemicals/cadmium
Cadmium. https://progressreport.cancer.gov/prevention/cadmium
Lead in food, foodwares, and dietary supplements. https://www.fda.gov/food/environmental-contaminants-food/lead-food-foodwares-and-dietary-supplements#:~:text=The%20FDA’s%20current%20IRL%20is,age%20(updated%20in%202022).
What are the U.S. standards for Cadmium Exposure?https://www.atsdr.cdc.gov/csem/cadmium/Safety-Standards.html#:~:text=A.,IDLH%20of%209%20mg%2Fm3.
Good article! I prefer milk chocolate over dark chocolate. Don’t they say dark chocolate is better for you too?
Thank you! I enjoy both but I do love dark chocolate. Dark chocolate has more cocoa compared to milk chocolate and so it has more flavanols. Flavanols lower blood pressure and likely help protect heart health. Flavanols can also help increase insulin sensitivity which is also a good thing too. The darker the chocolate, the more flavanols it has.