What to Do About Heavy Metals in Chocolate

Written by: Ryah Nabielski, MS, RDN

A recent Consumer Reports investigation found high lead and cadmium levels in popular brands of dark chocolate. As someone who loves chocolate and eats it daily, this news caught my attention! Do I need to stop eating chocolate?

On the one hand, I’m concerned about heavy metals and other toxins in my food. But on the other, cacao, the main ingredient in chocolate, is rich in polyphenols and has many demonstrated health benefits. I don’t want to take a nutritious food, or the pleasure it brings, out of my life unnecessarily.

In this article, I’ll discuss how heavy metals get in chocolate and what we can do about it. Keep reading to learn more about:

·      The Consumer Reports chocolate tests

·      What are heavy metals, and how they get into chocolate

·      How heavy metals are a food system-wide problem

·      How to eat chocolate safely (including suggestions for lead and cadmium-free chocolate and how to get rid of heavy metals)

Let’s jump into this important topic!

Inside the Report

Consumer Reports tested 28 popular chocolate brands, including several I’d consider high-quality for being organic, fair trade, and using quality ingredients. They found lead and cadmium in all the samples and levels above California’s Prop 65 standards in 23 samples. Prop 65 levels are some of the strictest in the country and world, many times lower than the highest dose that shows no health effect. [1]

But the issue of cadmium and lead in chocolate isn’t new. A 2018 study found elevated cadmium levels in cacao powder, cacao nibs, and other chocolate products available at the grocery store. So obviously, not much has changed since then. [2]

What Are Heavy Metals?

Heavy metals are minerals; they naturally exist in rocks and the earth’s crust. But these metals, including lead, cadmium, mercury, arsenic, and others, are now found in higher levels as free compounds displaced from rock and circulating in the environment. The release of metals from the earth is primarily due to human activity and industry creating heavy metal pollution.

Today, heavy metals circulate through soil, water, air, plants, animals, and humans.

Cadmium in Chocolate

Cadmium is a carcinogen released from mining and burning fossil fuels, a component of some pesticides, and found in cigarette smoke.

Cadmium is drawn from the soil into the cacao plant and is an issue of soil quality. Cadmium contamination in soil is one issue, but another problem is depleted nutrients in the soil from unsustainable agricultural practices. When soil is healthy, it contains beneficial minerals in robust quantities that displace cadmium uptake by the plant.

Interestingly, the genetics of the cacao species also influences cadmium uptake, with certain genetic variations being more protective. [3]

The cacao origin country may play a role because of differences in soil, cacao genetics, and other factors. One study found higher cadmium levels in chocolate from Latin America compared to Africa. [2]

Lead in Dark Chocolate

Lead is a toxic heavy metal that impairs cognitive development in infants and children. Primary lead sources are lead paint, pottery, and heavy metals in water. While lead poisoning from paint has decreased, lead is still an issue in many places (like Flint, Michigan).

Cacao beans aren’t a significant source of lead. Contamination of lead in chocolate occurs during the harvest and manufacturing processes. Environmental lead pollution from leaded gasoline and other sources accumulates on the cacao bean shells and contaminates the beans during fermentation, drying, transportation, and manufacturing. [4]

It’s Not Just Chocolate - Heavy Metals in Food Chain

Heavy metals in food are a system-wide problem that goes well beyond chocolate.

Research shows that cadmium is found in most food as it easily transfers from the soil into plants. Top food sources of cadmium in the United States are:

·      Lettuce

·      Spaghetti

·      Bread

·      Potatoes [5]

This study also showed that the highest cadmium intakes in proportion to body weight are in children 10 years old and younger. [5]

Other food sources of heavy metals include:

·      Packaged baby food (including organic options) – may contain lead, cadmium, and arsenic [6]

·      Rice and infant rice cereal – may contain arsenic [7]

·      Fish and seafood – may contain mercury

·      Protein powders – may contain lead and arsenic [8]

·      Edible mushrooms – may contain lead, nickel, and cadmium [9]

·      Turmeric – may contain lead [10]

So, it seems we don’t need to make chocolate the villain; the issues are with global pollution and the modern food supply. The solution for decreasing the effects of heavy metals on human health is to decrease heavy metals in food.

Action Steps for Safe Chocolate Consumption

I’m not one to suggest you stop eating chocolate, but with this knowledge we can make shifts in consumption to improve health. Here are some ways to balance cacao health benefits with the risks of toxic heavy metals:

·      Be a savvy consumer. Choose dark chocolate without lead and cadmium, as possible.

In the Consumer Reports study, the safest brands tested were:

o   Mast (organic)

o   Taza (organic)

o   Ghirardelli

o   Valrhona [1]

I also reached out to some of my favorite chocolate brands to find out if they test for heavy metals and their results. From what I know now, I’m also comfortable consuming chocolate from these brands:

o   Ora Cacao (use link for $5 discount)

o   Blue Stripes Urban Cacao

o   Dar Chocolate Art Bars Colorado

Pressure your favorite chocolate brands to up their game and provide you with a safer product. If you are a regular chocolate eater like me, consider eating less chocolate with known contamination or without testing data. And consider not giving chocolate with higher levels to your kids, who are more susceptible to the harmful effects of heavy metals in the body.

·      Eat more minerals. Just because you ingest heavy metals doesn’t mean you’ll absorb them into your body. Heavy metals compete with dietary minerals for absorption. For example, cadmium absorption occurs through the same mechanisms as iron, zinc, calcium, magnesium, and manganese. Cacao is a rich source of magnesium and other minerals that may displace cadmium. In addition, eating cacao with other mineral-rich foods and an overall mineral-rich diet may be supportive. [11]

·      Support heavy metal detox via sweating. The body excretes heavy metals via sweat, so sweating regularly is a good idea. One study found more metals in sweat after dynamic exercise vs. passive sweating (such as in a sauna). However, both have health benefits beyond heavy metal detox. [12]

·      Get tested. Ask your healthcare provider for heavy metal testing to learn about your exposures. Then, you can create a targeted plan to reduce exposure and promote detoxification.

After looking beyond the scary headlines about lead and cadmium in chocolate, I will keep chocolate in my life. But I’ll be even more mindful about the brands I choose and continue to tweak my lifestyle to minimize heavy metal exposure and support detoxification.

References

1.     Consumer Reports. (2022). Lead and Cadmium Could Be in Your Dark Chocolate. Accessed January 27, 2023.

2.     Abt, E., Fong Sam, J., Gray, P., & Robin, L. P. (2018). Cadmium and lead in cocoa powder and chocolate products in the US Market. Food additives & contaminants. Part B, Surveillance, 11(2), 92–102.

3.     Lewis, C., Lennon, A. M., Eudoxie, G., & Umaharan, P. (2018). Genetic variation in bioaccumulation and partitioning of cadmium in Theobroma cacao L. The Science of the total environment, 640-641, 696–703.

4.     Taylor D. A. (2005). Lead in Cocoa Products: Where Does Contamination Come From?. Environmental Health Perspectives, 113(10), A687–A688.

5.     Kim, K., Melough, M. M., Vance, T. M., Noh, H., Koo, S. I., & Chun, O. K. (2018). Dietary Cadmium Intake and Sources in the US. Nutrients, 11(1), 2.

6.     Consumer Reports. (2018). Heavy Metals in Baby Food: What You Need to Know. Accessed January 27, 2023.

7.     Karagas, M. R., Punshon, T., Davis, M., Bulka, C. M., Slaughter, F., Karalis, D., Argos, M., & Ahsan, H. (2019). Rice Intake and Emerging Concerns on Arsenic in Rice: a Review of the Human Evidence and Methodologic Challenges. Current environmental health reports, 6(4), 361–372.

8.     Consumer Reports. (2018). Arsenic, Lead Found in Popular Protein Supplements. Accessed January 27, 2023.

9.     Dowlati, M., Sobhi, H.R., Esrafili, A., FarzadKia, M., Yeganeh, M. (2021). Heavy metals content in edible mushrooms: A systematic review, meta-analysis and health risk assessment. Trends in Food Science & Technology, 109, 527-535.

10.  Cowell, W., Ireland, T., Vorhees, D., & Heiger-Bernays, W. (2017). Ground Turmeric as a Source of Lead Exposure in the United States. Public health reports (Washington, D.C. : 1974), 132(3), 289–293.

11.  Satarug, S., Garrett, S. H., Sens, M. A., & Sens, D. A. (2010). Cadmium, environmental exposure, and health outcomes. Environmental health perspectives, 118(2), 182–190.

12.  Kuan, W. H., Chen, Y. L., & Liu, C. L. (2022). Excretion of Ni, Pb, Cu, As, and Hg in Sweat under Two Sweating Conditions. International journal of environmental research and public health, 19(7), 4323.