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Podcast Recap | Is lead in chocolate something to worry about?

March 28, 2024

Dr. Frank J. Domino, professor in the Department of Family Medicine and Community Health at the University of Massachusetts, Chan Medical School, discusses the latest Consumer Reports (CR) testing of heavy metals in a variety of chocolates with guest Dr. Robert A. Baldor, professor and chair from the Department of Family Medicine at the UMass Chan Medical School - Baystate in Springfield, Massachusetts.

Podcast Length: 10 min.

5 Key Takeaways

1. Chocolate is just one potential source of heavy metal exposure that can occur from a variety of other sources such as drinking water, other foods, and other environmental factors.

Arsenic can be found in rice, mercury can be found in fish, cadmium can be found in spinach, and lead can be found in sweet potatoes and carrots. To the relief of health experts, when CR tested chocolate products, none of these products posed a specific risk of arsenic or mercury.

However, lead and cadmium are indeed concentrated in cocoa, the ingredient that gives chocolate its distinctive flavor. Cocoa plants take up cadmium from the soil, with the metal accumulating in cacao beans as the tree grows. However, lead can be deposited onto cocoa beans after harvest, potentially from dust and soil as the beans are drying outdoors. As a result, products rich in cocoa solids such as dark chocolate and cocoa powder tend to have higher heavy metal levels.

2. As much as one third of all tested chocolates had concentrations of lead and/or cadmium that were higher than California's maximum allowable dose. Detectable levels of lead and/or cadium were actually found in all chocolate products tested.

CR experts initially tested 28 dark chocolate bars for lead and cadmium in December 2022.

Then in October 2023, they tested 48 different chocolate products including cocoa powder, chocolate chips, milk and dark chocolate bars, brownie mixes and hot chocolate preparations. Products tested included big name brands such as Hershey's, Ghirardelli, and Nestle, and they looked at national retailers such as Costco, Target, Trader Joe's, Walmart, Whole Foods, and some specialty makers as well.

To determine the risks related to cadmium and lead levels, CR testers compared product measured levels to California's standard maximum allowable dose levels (MADL) for lead (0.5 microgram) and cadmium (4.1 mcg) per day. There are no federal limits for the amount of lead and cadmium most foods can contain.

Sixteen of the 48 products had amounts above CR-identified levels of concern for at least one of the heavy metals—in some cases more than twice the limit. However, CR also identified safer alternatives in each category of chocolate products.

3. Dark chocolate, despite its purported antioxidant properties, has more heavy metal concentrations, specifically lead and cadmium, than milk chocolate. For those who still prefer dark chocolate over milk chocolate, however, occasional dark chocolate consumption won’t necessarily expose them to extremely high levels of heavy metals.

CR testers found lead or cadmium levels above the stated thresholds in five of the seven dark chocolate bars that they tested. But that does mean that a quarter of the products tested fell below the standard levels of concern.

To put these lead levels in context, Dr. Baldor compares lead levels found during the recent public health water crisis in Flint, Michigan. None of the chocolates tested contained levels of lead comparable to what was found in the drinking water in Flint, Michigan, which amounted to 3.5 microgram per day or seven times the California standard for acceptable lead levels.

For nonpregnant adults who choose to eat dark chocolate, Dr. Baldor suggests picking brand products that CR testing identified as having lower levels of heavy metals. Interestingly, experts found no relationship to the price of the chocolate products and the levels of heavy metals that they contain.

Milk chocolate is an option for those who want to limit heavy metal exposure. None of the five milk chocolate bars tested by CR were over the limits for heavy levels. Nonetheless, milk chocolate is packed with more sugar than dark chocolate, and should still be consumed in moderation.

So while there's no need to test lead levels in "chocoholic" patients, Dr. Baldor says to "certainly ask about chocolate intake if you're seeing a patient where there's a concern for lead poisoning or heavy metal poisoning." Frequent lead exposure has been linked to immune system problems, anemia, kidney disease, neuropathies, and chronic abdominal pain.

4. Kids and pregnant people should consume dark chocolate sparingly, if at all.

Heavy metals pose the highest neurodevelopment risk to young children and developing babies.

5. When consuming hot chocolate, brownies, chocolate cake, and other cocoa-containing products, know that they can contribute to one's overall heavy metal burden. As with other types of chocolate, these are best consumed in moderation.

Four of the six hot chocolate mixes, which contain cocoa powder, also exceeded the lead level limits.

None of the 12 chocolate chip products tested had high levels of cadmium and only two of them were slightly over the levels for lead. However, Dr. Baldor notes that serving sizes matter here. A serving size for chocolate chips is about a tablespoon—consuming two or more servings can put one well above the daily limit on chocolate chips.

And, of course, individuals should limit how much they eat of other foods that tend to be high in heavy metals, such as rice and rice products, carrots, and sweet potatoes.

Any views, thoughts, and opinions expressed in this podcast recap are solely that of the host and guests and do not reflect the views, opinions, policies, or position of epocrates and athenahealth.

Source:

Frank J. Domino (Host). (2024, March 18). Chocolate—Get the Lead Out! Frankly Speaking Episode 372. Frankly Speaking About Family Medicine. [Audio podcast episode]. https://podcasts.apple.com/us/podcast/chocolate-get-the-lead-out-frankly-speaking-ep-372/id1194659367?i=1000649513079

Resources:

Loria, Kevin. (2023, October 25). Consumer Reports. A Third of Chocolate Products Are High in Heavy Metals, CR's Tests Find. https://www.consumerreports.org/health/food-safety/a-third-of-chocolate-products-are-high-in-heavy-metals-a4844566398/

Loria, Kevin. (2022, December 15; updated 2023, October 25). Consumer Reports. Lead and Cadmium Could Be in Your Dark Chocolate. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/