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Heavy Metals in Your Dark Chocolate?

Many people, including Dr. Johnson, tend to grab a piece of dark chocolate when looking for a guilt-free sweet treat. But unfortunately, a recent investigation revealed that most dark chocolates from a variety of different brands contain concerningly high levels of heavy metals, including lead, cadmium, or both.

In this blog, we’ll break down what this means, why heavy metals are in our chocolate, and what to do about it.

The report:

In mid-December, Consumer Reports published an investigation revealing that 23 out of 28 chocolate bars they tested from a number of brands contained alarming levels of lead, cadmium, or both. This was especially surprising, given that dark chocolate typically has a good reputation- with previous studies demonstrating that dark chocolate has been associated with lower blood pressure, reduced risk of heart disease, and improved cholesterol levels. Moreover, as we reported last year, cocoa even contains naturally acting antidepressants and amino acids that are used to create serotonin, making us feel happy and satisfied. So, this news of heavy metals in dark chocolate is pretty shocking.

The Consumer Reports investigation found results similar to that of a comprehensive study of cocoa and chocolate products from 2018 by the Food and Drug Administration. The FDA’s study revealed that dark chocolate, on average, contained 7.6 micrograms of cadmium and 0.8 micrograms of lead per one-ounce serving. However, some of the chocolate they tested contained three or four times as much. Surprisingly, the chocolate with the least amount of heavy metals was milk chocolate, as it contains the least cocoa.

When compared to 300 other foods in a separate study by the FDA, dark chocolate had the third-highest concentrations of both cadmium and lead. Only baking powder and cocoa powder contained more lead and cocoa powder and sunflower seeds contained more cadmium. But this comes as no surprise to researchers and chocolate companies, who have been aware of the high levels of cadmium and lead in cocoa products for decades.

So, how do heavy metals get into chocolate in the first place?

Cadmium and lead are both naturally occurring elements that typically remain in the Earth’s crust, but human activity like mining, transportation, agriculture, and manufacturing have increased their levels in the water, air, and soil. Essentially, these heavy metals are all around us, thus, it’s not too surprising that they end up in our food supply too. Experts have said that total avoidance of lead and cadmium is impossible.

It’s well known that toxins like lead and cadmium will harm the body, but this is especially true for children and pregnant women. Lead has especially damaging effects on the nervous system, but impacts nearly every organ system in the body. Long exposure to cadmium has been linked to bone fragility and lung and kidney damage.

Because these toxins cannot be tested on humans directly, it’s difficult to estimate how much of a substance is enough to be harmful. Moreover, food safety standards regarding heavy metals are different in every country. In the US, the U.S. Agency for Toxic Substances and Disease Registry set the “minimal risk level” for daily cadmium intake to around 6 micrograms for a person weighing 130 pounds. A 2019 study found that Americans consume an average of 5 micrograms of cadmium per day from food sources. Moreover, a single serving of some dark chocolate brands will be over 6 micrograms.

There is no established safe intake level for lead in the US. This is because even the smallest amount of lead in the blood has been associated with adverse neurodevelopmental effects in children. However, the FDA does have a recommended maximum for lead in candy. If the maximum is passed, then sales can be limited by the agency. Thankfully, the amount of lead in dark chocolate is typically lower than this maximum.

What’s a chocoholic to do?

The good news is that you don’t have to give up entirely. Just be sure to enjoy it in a moderation and as a part of a varied diet. You can also check the amount of heavy metal in your chocolate on As You Sow- this website keeps track of lead and cadmium levels in products from many chocolate brands.

According to As You Sow, the five best dark chocolates containing the least amount of lead and cadmium are:

  • Mast Organic Dark Chocolate (80% cacao)

  • Ghiradelli Chocolate Intense Dark (86% cacao)

  • Taza Organic Deliciously Dark Chocolate (70% cacao)

  • Valrhona Abinao Dark Chocolate (85% cacao)

  • Ghirardelli Chocolate Intense Dark Twilight Delight (72% cacao)

The investigation from Consumer Reports also makes several recommendations on how to minimize risks while still enjoying your favorite dark chocolates:

  1. Prioritise dark chocolates with the lowest levels of heavy metals → The Consumer Reports study found only five chocolates (listed above) that contain relatively low levels of lead and cadmium.

  2. Stick to dark chocolates with lower cacao percentages → Instead of grabbing a bar of 80% cacao, try a 70% one, for example. Consumer Reports testing found that cadmium levels tend to increase with cacao percentages. However, lead levels do not share the association.

  3. Don’t assume organic is safer, in this case, → Unfortunately, the Consumer Reports investigation found that organic dark chocolate bars were just as likely to have high levels of heavy metals as non-organic brands.

  4. Treat chocolate as an indulgence → The more you eat dark chocolate, the more you risk consuming higher levels of cadmium and lead, so it’s best to cut back and save dark chocolate for your special occasions.

  5. Don’t give kids as much dark chocolate → The younger you are, the bigger the threat from heavy metal exposure. Pregnant people should limit their consumption as well.

The next time you're craving chocolate, be sure to check As You Sow to make sure you’re not accidentally also getting a dose of heavy metals with your sweet treat.

To learn more about the Johnson's Center, click here to contact us! If you have any more questions about your path to optimal health, email our office at or call 276-235-3205.

The Johnson Center for Health services patients in-person in our Blacksburg and Virginia Beach / Norfolk locations. We also offer telemedicine for residents of Virginia and North Carolina!


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