Should I stop eating dark chocolate because of lead and heavy metals? 

Are there heavy metals in dark chocolate? Yes. Am I quitting chocolate? No. Why? Because there’s heavy metals in everything. We also have LOTS of science showing the health benefits of dark chocolate. Not to mention, how synergistic minerals within dark chocolate help our body’s own natural detoxification process. Let’s look at the science so you can determine: Should I stop eating dark chocolate because of lead and heavy metals?

Health Benefits of Dark Chocolate

“Dark chocolate’s reputation as a relatively healthy treat stems mostly from the cocoa solids. These are packed with flavanols, which are antioxidants linked to improved blood vessel function, reduced inflammation, and lower cholesterol. Dark chocolate is also lower in sugar and higher in fiber than milk chocolate, and it has magnesium and potassium. Unfortunately, cocoa solids are also where the heavy metals, especially cadmium, lurk.” (5)

ConsumerLabs (independent from Consumer Reports) found amounts of flavanols among products varied widely:

  • Dark chocolate bars (40 gram serving): 136.4 mg to 560.8 mg
  • Dark chocolate chips (15 gram serving): 79.2 mg to 143.6 mg
  • Cocoa powders (1 tablespoon — 5 grams): 13.1 mg to 124.8 mg
  • Cacao nibs (30 gram serving): 364.5 mg to 677.1 mg
  • Cocoa supplements (1 serving): 0.23 mg to 753.5 mg

Dutched (alkali processed) cocoas and chocolates generally had lower flavanol concentrations, as the Dutching process reduces flavanol levels. (14) Subsequently, they also have less heavy metals.

How much cocoa or dark chocolate do I need for health benefits?

Based on ConsumerLabs the amount of flavanols needed for the following benefits are:

  • Cardiovascular health: About 200 to 900 mg per day
  • Blood sugar/insulin improvement: About 200 mg to 600 mg per day
  • Memory/cognitive function: About 500 to 900 mg per day
  • Skin elasticity/wrinkles: 320 mg per day (15)

320mg seems to be an average in nearly all categories, so we’ll use that as the standard in reviewing for heavy metal loads below.

Furthermore, flavanols ranged from 1 mg to 374 mg in cocoa powders and mixes (187mg average assumed) and 2 mg to 351 mg in dark chocolates (174.5mg average assumed). For our purposes, that would mean 2 servings a day would achieve health benefits (on average).

Consumer Report: Lead and Cadmium Could Be in Your Dark Chocolate

“Consumer Reports found dangerous heavy metals in chocolate from Hershey’s, Theo, Trader Joe’s, and other popular brands.”

Full disclosure: I’m a little irritated by this report and think it’s a bit click-baity. This is not new news. We’ve known about contamination of confectionaries since 1820 and news about heavy metals in chocolate for years! Yes, the heavy metals are dangerous, but they’re also all around us and our bodies are literally made to detox them. So, in what quantity (i.e. how great the risk) are we talking? Let’s get into all of it!

What was CR’s definition of “dangerous”?

The methodology basis for the study:

Good: “We tested 2-3 samples with at least two distinct lot codes of each model”

Good: The samples were masked, blind coded to preserve their, identities, and shipped overnight to an independent, accredited laboratory for the analyses.” Additional notes are included about preparation to avoid contamination and bias.

Where it’s not as good (IMO): “We used California’s maximum allowable dose level (MADL) for lead (0.5 micrograms) and cadmium (4.1mcg). Shown are the percentages of the MADL supplied in an ounce of each chocolate.”

The FDA limits are more than 17x what CR used for lead (2.2 micrograms (µg) per day for children and 8.8 µg per day for females of child bearing age) (3). CR’s set their “danger” at .5 µg per day. Because of this difference, I feel that the dangers are exaggerated.

the Consumer Report utilized a lower threshold than FDA or EPA for Lead and Cadmium

We can’t remove heavy metals but can reduce them:

The EPA and FDA standards are serving as effective when measured in children 1-3 yo. (3) According to the FDA, their changes implemented in the 1980’s have subsequently drastically reduced dietary lead levels by 97%.

“While it is not possible to prevent or remove lead entirely from foods, the levels in food can be reduced. By law, food manufacturers have a responsibility to implement controls as needed to significantly minimize or prevent exposure to chemical hazards—including lead.

To determine if the level of lead in a food is a potential health concern, we consider the toxicity of lead and exposure based on the level of lead measured in the food and consumption.” (3)

CR’s Risk Assessment:

“For 23 of the bars, eating just an ounce a day would put an adult over a level that public health authorities and CR’s experts say may be harmful for at least one of those heavy metals. Five of the bars were above those levels for both cadmium and lead.”

However, NONE of the chocolates would have exceeded FDA standards. California proposition 65 lead limit for supplements is 0.5 mcg per day. Meanwhile, the EPA (US Environmental Protection Agency) safe lead limit for drinking water is 15 mcg/L. To use Prop 65 standards, 2 oz (one-fourth cup) of the water considered safe by the EPA would bring you beyond the safe daily limit.

Understanding Prop 65 standards:

Proposition 65 for California serve as guidance for a consumer “warning,” for buyers to make informed choices. For example, if you live in California you can then see all of the foods you purchase that have a Prop 65 warning for Lead and determine your cumulative risk.

It does not mean that one item is banned or will lead to ill health effects at that level. From their own website, the limits were not set with that value in mind. (4)

I do take it for what it’s worth: a warning. So if we’ve been warned, what else do we need to know in order to be empowered to make a choice for ourselves?

How does Lead Get in Cacao Beans

As a result of a lawsuit against chocolate manufacturers and As You Sow, more research has been done since 2019. It was determined that the cacao plants take up cadmium from the soil, with the metal accumulating in cacao beans as the tree grows. That’s similar to how heavy metals contaminate some other foods, and not something that’s easily mitigated. And, the acceptable levels are even higher than lead (8x), which is why that’s where I’m choosing to focus my research.

However, Lead appears to enter the cacao after beans are harvested. It was found typically on the outer shell of the cocoa bean, not in the bean itself. Moreover, lead levels were low soon after beans were picked and removed from pods but increased as beans dried in the sun for days. This suggests it was the cross-contamination with the drying surface, gas emissions, or dust in the air that added lead, after it was removed from the pod.

Another reason fossil fuels are problematic! “Because of the high capacity of cocoa bean shells to adsorb lead, contamination from leaded gasoline emissions may occur during the fermentation and sun-drying of unshelled beans at cocoa farms… most contamination occurs during shipping and/or processing of the cocoa beans and the manufacture of cocoa and chocolate products.” (13)

What about in chocolate specifically?

“Although the lead content of cocoa beans is as low as or lower than those of hundreds of different foods in the United States and elsewhere, lead concentrations of manufactured cocoa are among the highest of all foods.” (13)

As a consumer, my top priority is going to be in purchasing cocoa powder that tests for heavy metals because that way I know I’m getting safe products. Even better, AsYouSow regularly tests and publishes results of chocolates here. I share a cross-reference of how to maximize getting the flavanols within FDA’s ranges of safe consumption at the end of this article. Subsequently, I’ve made a decision:

Why I’m NOT Quitting Dark Chocolate

1) There are protective nutrients in chocolate.

Often we find nature knows best. Synergistic nutrients, those that come together in a whole food source, are often the most used by our body. Which the FDA included in their website, too. They say, “The agency considers the health effects of the ‘whole food,’ which includes the potential harmful health effects of specific contaminants that may be present, as well as the food’s nutrients…” (3)

As mentioned before, dark chocolate specifically provides antioxidant and other health benefits: a rise in magnesium in tissues serves to combat the harmful effects of an increase in these heavy metals. (8).

In fact, magnesium can remove a variety of toxins and heavy metals from your body – including lead, aluminum, and mercury. In a study (way back in 1979!) we saw that urinary excretion of lead was higher in rats fed magnesium. Magnesium helped mobilize lead from the bone, thus increasing the blood lead level temporarily until subsequent urinary excretion. (17)

And guess what?

Dark chocolates are confirmed as an excellent source of magnesium (252.2 mg/100 g) and iron (10.9 mg/100 g): in chocolate containing 90% cocoa, their content corresponds to, respectively, 67.0% and 80.3 of Nutrient Reference Values (NRV) in the European Union. The chocolate containing 90% cocoa is also a good source of zinc (3.5 mg/100 g), which is important for the immune system, and selenium (0.1 mg/100 g). Three main components suitable to explain the mineral concentrations are analyzed by factor analysis. The component 1 can be interpreted as the contribution from the cocoa beans, owing to the mineral characteristics of the soil in which they have grown; the component 2 is mainly due to the manipulation and transformation of the cocoa in chocolate, while the component 3 represents the milk powder. (18)

To be clear: One dark chocolate bar (9oz) is 90% of your daily recommended magnesium. That’s how much there is!

Another study quote that gave me confidence, “Our investigations indicated that [Lead absorption] is reversible and that increased intake of Magnesium eliminates Lead via urine.” (8)

2) Incorporate other detox protectors, like probiotics.

Probiotics are incredibly helpful! I personally use a soil-based brand that doesn’t require refrigeration and has been clinically tested as effective as a powerful antioxidant for your gut.

“Some species of lactic acid bacteria (LAB) including Lactobacillus rhamnosus, L. plantarum, and Bifidobacterium longum are capable of binding heavy metals… Moreover, LAB are known to have antioxidative properties in human subjects, which may be another important characteristic for heavy metal toxicity protection.” (7)

3) The bioavailability of heavy metals in chocolate is even less than we thought!

Not only is the chocolate itself protective, and probiotics additional benefit; but, a study was done to specifically look at how much of the heavy metals are available for your body to absorb. It’s good news!

“The bioavailability of Cadmium (Cd) and Lead (Pb) from cocoa powder, liquor and butter was evaluated using a sequential enzymolysis approach. The data obtained as a function of the geographical origin of the samples indicated strong differences not only in terms of the total Cd and Pb concentrations, but also with regard to the bioavailability of these metals. The Cd concentrations in the cocoa powders varied from 94 to 1833 microg kg(-1), of which 10-50% was potentially bioavailable. The bioavailability of Pb was generally below 10% and the concentrations measured in the cocoa powders were in the 11-769 microg kg(-1) range. Virtually all the Cd and most of Pb were found in the cocoa powder after the pressing of the liquor.” (10)

Y’all, so even when you see that numbers of heavy metals are high in chocolate, only 10-50% of that is even bioavailable for you to absorb.

4) Incorporate antioxidant-rich foods to support your own detox if you enjoy dark chocolate:

Antioxidant-rich plants (fruits and vegetables) are also supportive for your body. Specifically recommended are:

  • tomatoes (rich in iron, calcium, selenium, zinc, vitamins B and C, quercetin and naringenin),
  • berries (rich in essential elements, vitamin C, anthocyanin and catechin),
  • onions (rich in selenium, quercetin and vitamins B and C),
  • garlics (rich in sulphur-containing compounds, essential elements and vitamins C and E), and
  • grapes (rich in vitamins, essential elements and anthocyanin) are of special importance as natural antagonists to Cd and Pb toxicity and should be consumed on a regular basis. (7)

Is milk chocolate safer?

For contamination, yes – but only because there is less actual cocoa. And, less nutritional benefit accordingly.

“The results indicated that dark chocolates have higher concentrations of Cd and Pb than milk and white chocolates.” (10)

As CR indicates, “People also choose dark chocolate in particular for its potential health benefits, thanks to studies that suggest its rich supply of antioxidants may improve heart health and other conditions, and for its relatively low levels of sugar… But there’s a dark side to this “healthier” chocolate. Research has found that some dark chocolate bars contain cadmium and lead—two heavy metals linked to a host of health problems in children and adults.”

“Cd and Pb were significantly correlated with percent cocoa, with correlations varying by product type and geographic origin. Geographic variation was observed for Cd, with higher Cd concentrations found in products reported as originating from Latin America than from Africa.” (9)

What is recommended?

Based on the AsYouSow test results, here is a listing of tested dark chocolates. I only looked at dark chocolate, but we have established it as the highest risk factor – which was consistent with what was on their report as well. Reminder: FDA recommended levels are 2.2 µg per day for children and 8.8 µg per day for females of childbearing age.

Product

Lead µg/
serving

Hershey’s Cocoa 100% Cacao Natural Unsweetened 0.4
M&Ms Dark Chocolate 0.2
Swiss Miss Indulgent Collection Dark Chocolate Hot Cocoa Mix 0.5
Ripple Brand Collective barkTHINS Dark Chocolate Almond with Sea Salt 1.0
Starbucks Chocolate covered Espresso Beans 0.4
Russell Stover Assorted Fine Chocolates (only darkest chocolate tested) 0.6
Ojio Organic Cacao Powder Ethically Sourced – Peru 0.7
Moonstruck Dark Chocolate – 68% cacao 1.0
Dove Silky Smooth Dark Chocolate Bar 0.4
Lily’s Sea Salt Extra Dark Chocolate 70% ~ Stevia Sweetened 1.1
Lily’s Original Dark Chocolate Stevia Sweetened 55% Cocoa Non GMO 0.7
Guittard Nocturne Organic Bittersweet Chocolate Baking Wafers 74% Cacao 0.2
Guittard Unsweetened Chocolate Gourmet Baking Bars 0.1
Guittard Grand Cacao Sweet Ground Chocolate 53% Cacao can 0.2
Godiva Chocolatier 72% Cacao Dark Chocolate 1.4
Ghirardelli Chocolate Premium Baking Bar 100% Cacao Unsweetened Chocolate 0.3
Ghirardelli Chocolate Premium Baking Bar 60% Cacao Bittersweet Chocolate 0.1
Ghirardelli Chocolate Premium Baking Cocoa 100% Unsweetened Cocoa (powder) 0.5
Ghirardelli Chocolate Intense Dark Twilight Delight 72% Cacao 0.2

Endangered Species Chocolate Strong + Velvety Dark Chocolate 88% Cocoa

1.8
Endangered Species Chocolate Bold+Silky Dark Chocolate 72% Cocoa 1.5
Equal Exchange Organic Fairly Traded Dark Chocolate Very Dark 71% Cocoa 0.3
Equal Exchange Organic Fairly Traded Extreme Dark Dark Chocolate 88% Cacao 0.4
Equal Exchange Organic Fairly Traded Dark Chocolate Panama Extra Dark 80% Cacao 0.3
365 Everyday Value Organic Dark Chocolate 57% Cacao 0.5
Whole Foods Tanzania Schoolhouse Project – 72% cacao Organic Dark Chocolate 1.0
Sprouts Farmers Market Dark Chocolate 72% Cocoa 0.5
Navitas Naturals Cacao Powder Certified Organic Mayan Superfood 0.8
Green & Black’s Organic Dark 70% Cacao Content 1.3
Divine 85% Dark Chocolate 0.5
Chocolove Dark Chocolate- 55% Cocoa Content (variety of flavors: peppermint, chilies & cherries, raspberries, ginger) 0.3
Chocolove Extreme Dark Chocolate 88% Cacao Content 0.4
Lindt Gold Bunny Dark Chocolate 0.5
Lindt Excellence Dark A Touch of Sea Salt 0.1
Lindt Dark Chocolate Truffles 0.3
Lindt Excellence 85% Cocoa Extra Dark Chocolate Bar 1.1
Alter Eco Deep Dark Super Blackout Chocolate 0.3

Les Mini Grammes De Chocolat Noir Infini 99 dark chocolate bag

1.9
Tony’s Chocoloney Dark Chocolate 70% bar 0.9
Trader Joe’s The Dark Chocolate Lover’s Chocolate Bar 85% Cacao (Tumaco) 0.6
Trader Joe’s Dark Chocolate 73% Cacao Super Dark (organic) 0.6
Trader Joe’s Swiss 72% Cacao Dark Chocolate 1.4
Trader Joe’s Pound Plus – 72% Cacao Dark Chocolate 1.1
Theo Organic Extra Dark Pure Dark 85% Dark Chocolate 0.5
TCHO Extra Dark 81% Cacao1 1.3
Taza Chocolate Toffee Almond & Sea Salt 60% Dark 0.1
Taza Chocolate Wicked Dark with Toasted Coconut 95% Dark 0.1
Ritter Sport Dark Chocolate 74% Cacao Intense with Cacao From Peru 0.8
Ritter Sport Dark Chocolate 81% Cacao Extra Intense with Cacao from Ghana 0.4
Enjoy Life Eat Freely boomCHOCOboom Bar Dairy, Nut & Soy Free; Gluten Free Dark Chocolate No Artificial Anything! 1.1
Baker’s Unsweetened Baking Chocolate Bar 0.6
Sam’s Choice Swiss Dark Chocolate 90% Cocoa 0.3
SunSpire Organic Fair Trade 44% Cacao Chocolate Chunks 0.3
Shiloh Farms Dark Chocolate Chips 0.5

*the suggested serving size average to maximize health benefits of flavanols

If you don’t see your favorite brand or style above, checkout AsYouSow’s chart. You can search by brand, as well as sort by both Lead and Cadmium levels.

How much for health benefits?

What does that mean if we want to maximize getting the flavanols within FDA’s ranges of safe consumption? For example, if your goal is to optimize the health benefits (320µg, or 2 servings), here’s how much that is with some of my favorites:

Product Lead µg/
serving
Serving
Size
total Lead
for 320 µg
flavanols
Lily’s Sea Salt Extra Dark Chocolate 70% ~ Stevia Sweetened 1.1µg 40g 2.2µg
Baker’s Unsweetened Baking Chocolate Bar 0.6µg 14g 1.2µg
Guittard Nocturne Organic Bittersweet Chocolate Baking Wafers 74% Cacao 0.2µg 15g 0.4µg
Godiva Chocolatier 72% Cacao Dark Chocolate 1.4µg 34g 2.8µg
Ghirardelli Chocolate Premium Baking Cocoa 100% Unsweetened Cocoa (powder) 0.5µg 6g 1.0µg
Equal Exchange Organic Fairly Traded Dark Chocolate Very Dark 71% Cocoa 0.3µg 37g 0.6µg
Navitas Naturals Cacao Powder Certified Organic Mayan Superfood 0.8µg 15g 1.6µg
Green & Black’s Organic Dark 70% Cacao Content 1.3µg 30g 2.6µg
Divine 85% Dark Chocolate 0.5µg 28g 1.0µg
Chocolove Dark Chocolate- 55% Cocoa Content (variety of flavors: peppermint, chilies & cherries, raspberries, ginger) 0.3µg 30g 0.6µg
Lindt Dark Chocolate Truffles 0.3µg 36g 0.6µg
Alter Eco Deep Dark Super Blackout Chocolate 0.3µg 30g 0.6µg
Tony’s Chocoloney Dark Chocolate 70% bar 0.9µg 50g 1.8µg
Trader Joe’s Dark Chocolate 73% Cacao Super Dark (organic) 0.6µg 33g 1.2µg
Enjoy Life Eat Freely boomCHOCOboom Bar Dairy, Nut & Soy Free; Gluten Free Dark Chocolate No Artificial Anything! 1.1µg 32g 2.2µg
SunSpire Organic Fair Trade 44% Cacao Chocolate Chunks 0.3µg 15g 0.6µg
Shiloh Farms Dark Chocolate Chips 0.5µg 34g 1.0µg

Specifically excluded on purpose (and why)

These items are within adult standards, but not included as recommended because they exceed children’s recommended limits per day per serving.

Products Lead µg/
serving
NOW Healthy Foods Certified Organic Cocoa Powder 100% Pure 7.5
365 Everyday Value Organic Dark Chocolate Coconut 56% Cacao 6.0
Theo Organic Fair Trade Almond Coconut 65% Dark Chocolate Limited Edition Spring Collection 4.5
Theo Organic Fair Trade Coconut 70% Dark Chocolate 3.9
Sprouts Farmers Market Dark Chocolate 72% Cocoa 3.7
Sunfood Super Foods Raw Cacao Powder- Certified Organic 3.6
Valrhona Poudre de Cacao cocoa powder 100% cacao 3.6
Endangered Species Chocolate Natural Dark Chocolate with 88% Cocoa 3.4
Chocolove Extra Strong Dark Chocolate- 77% Cocoa Content 3.3
Taza Chocolate Chocolate Mexicano Super Dark Mexican-Style Stone Ground Chocolate Organic & Direct Trade 85% Dark 3.0
Godiva Chocolatier 85% Cacao Extra Dark Santo Domingo Chocolate 3.0
Navitas Naturals Cacao Powder Certified Organic Mayan Superfood 2.9
Dagoba Organic Chocolate Eclipse Extra Strong Dark Chocolate- 87% Cacao 2.8
Lindt Excellence 85% Cocoa Extra Dark Chocolate Bar 2.8
Moonstruck Dark Chocolate Chile Variado – 68% Cacao 2.5
Gelson’s Finest 72% Cocoa Dark Chocolate 2.2
Hershey’s Special Dark Mildly Sweet Chocolate Bar 2.4

I’m not the only one

What’s our guru say? Lindsay Dahl is an expert on all things non-toxic living with a balanced, scientific perspective. I loved her take on this topic:

from Lindsay Dahl, love her takeaways:

Heavy metals are nearly impossible to avoid, but are also deemed some of the most toxic substances on earth, what are we to do?

1. Be wary of “heavy metal free” products because brands making claims like this are making false promises.

2. The federal government needs to establish health protective limits such as they just did in infant formula.

3. Brands need to test their finished goods and carefully source naturally derived raw materials.

4. Be mindful if you’re consuming a high volume of products like rice milk, teas, or agricultural products coming from areas that have higher risk for heavy metals from the soil (byproduct of manufacturing, legacy pollution etc).

The goal is to stay informed and push brands and our government to do better without going down a rabbit hole of control.

Stay in touch!

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References:

  1. Lead and Cadmium Could Be in Your Dark Chocolate, Consumer Reports, 2022
  2. Test Methodology for Heavy Metals in Chocolate Bars, Consumer Reports, 2022
  3. Lead in Food, Foodwares, and Dietary Supplements, FDA.gov
  4. Lead and Lead Compounds, Proposition 65 Warnings updated 2018, CA.gov
  5. Impact of cocoa flavanols on human health, 2021, PMID: 33722594
  6. Toxins in Chocolate, AsYouSow.org
  7. Dietary Strategies for the Treatment of Cadmium and Lead Toxicity, 2015, PMCID: PMC4303853
    PMID: 25594439
  8. Contribution to interaction between magnesium and toxic metals: the effect of prolonged cadmium intoxication on magnesium metabolism in rabbits, 1998, PMID: 9884986
  9. Cadmium and lead in cocoa powder and chocolate products in the US Market, 2018, PMID: 29310543
  10. Cadmium and lead in chocolates commercialized in Brazil, 2014, PMID: 25123980
  11. Concentrations and bioavailability of cadmium and lead in cocoa powder and related products, 2003, PMID: 12775476
  12. Toxic Metal levels in cocoa powder and chocolate by ICP-MS method after microwave-assisted digestion, 2018, PMID: 29287336
  13. Lead Contamination in Cocoa and Cocoa Products: Isotopic Evidence of Global Contamination, 2005,PMCID: PMC1281277; PMID: 16203244
  14. We Found the Best Dark Chocolates and Cocoas With the Least Contamination, 2020, ConsumerLabs.com
  15. Dark Chocolates, Cocoa & Cacao Powders, Nibs, and Supplements Review, 2023, ConsumerLabs.com
  16. Toxins in Chocolate, AsYouSow.org
  17. Intake of magnesium and toxicity of lead: an experimental model, 1979, PMID: 453925
  18. Mineral essential elements for nutrition in different chocolate products, 2016, PMID: 27346251

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