As a nutrition psychiatrist and self-proclaimed chocoholic, I regularly promote dark chocolate to my patients for its health benefits, especially around Valentine’s Day. Recently, Consumer Reports and Consumer Labs, which are both third-party testing agencies, separately found that eating just one ounce of some of the most popular dark chocolate bars could expose one to harmful levels of cadmium and/or lead. After reading both studies I was deeply curious to get to the bottom of these findings and figure out how to choose optimal products for myself and my patients.
The cocoa bean has been sought after for over 5000 years. Cocoa beans were first cultivated by the Mayan people. Millenia later the Aztecs believed cocoa pods were an elixir because of their fortifying, nourishing, and aphrodisiac qualities. In modern times, researchers have found that the cocoa bean itself contains a healthy dose of antioxidants known as polyphenols, which enhance nitric oxide in the brain as well as in our nether regions, and hypothesized that cocoa works as nature’s Viagra (though current evidence doesn’t show direct sexual effects). The subcomponents of polyphenols (polyphenic acid, resveratrol, flavonol, anthocyanins, flavan-3-ols) confer incredible health benefits – namely improved blood sugar regulation, a decrease in LDL cholesterol, improved arterial function and increased levels of dopamine, which can lower depression and prevent neurocognitive decline with just 500mg to 1g of daily dark chocolate consumption
While the health benefits and allure of chocolate is as old as time, the heavy metals found in our modern chocolate varieties are new and concerning. Recent studies from Consumer Reports tested 28 types of chocolate bars for cadmium and lead levels. It found only 5 varieties were deemed safe for daily consumption. Consumer Labs tested a variety of cocoa powders, nibs, and cocoa supplements with high market popularity from 2019 to 2022 for both heavy metals as well as the potency of flavanols. Consumer Labs found that in general chocolate products with cocoa beans sourced from Latin America were the highest in cadmium compared to beans sourced from Africa. Cocoa powder had more cadmium than dark chocolate and dark chocolate had more than milk chocolate. Paradoxically, organic chocolate had higher cadmium than non-organic brands.
For context, the U.S. government does not regulate cadmium in food or supplements. California Proposition 65 allows for a daily cadmium limit of 4.1 mcg/day, while European regulations limit cadmium to 0.6 mcg/gram of cocoa powder. Even so, most cocoa powders tested had far more cadmium than European regulations would allow. To learn more, watch my interview about chocolate with Furthermore Ventures.
How concerned should I be about heavy metal exposure in chocolates?
Heavy metals are ubiquitous, occurring in nature across a wide variety of foods.
Cadmium is an essential trace mineral, found in fruits, vegetables, wheat, and shellfish. Typical consumption in the US is 25-60 mcg per day. Higher concentrations are absorbed in produce primarily due to soil contamination from the use of pesticides, which is worrying because high consumption of cadmium can accumulate in various tissues and organs, particularly in the kidneys. The main risks are lower IQ in children and in adults, renal damage and infertility.
Lead is found widely distributed in nature in soil, dust, air, water, and food. Elevated levels are neurotoxic and well-established as causing low IQ in children. While trace amounts of lead are found in chocolate, no chocolate products outside of pre-mixed hot cocoa powders were found to have excess amounts of lead. If you have children, buy a low-cadmium pure cocoa powder and make your own.
What chocolate products can I continue to enjoy?
365 Whole Food Organic Unsweetened Cocoa Powder
Good & Gather (Target) Unsweetened Cocoa
Ghirardelli Premium Baking Cocoa 100%
Ghiradelli Baking Chips 60% Bittersweet
Ghirardelli 72% Intense Dark Cacao Chocolate
Trader Joe’s Pound Plus 72%
Montezuma’s Absolute Black 100%
Choc Zero, Sugar-Free
Endangered Species Strong + Velvety 88%
Lily’s Sea Salt Extra Dark 70%
Baker’s Semi-Sweet 56%
Hu Salty 70%
Which chocolate products had the most cadmium?
Trader Joe’s Organic Fair Trade Powder
Navita’s Organic Cocoa Powder
Hershey’s Cocoa Special Dark
Alter Eco Deep Dark Blackout
Evolved Midnight Coconut
Trader Joe’s Midnight Uganda 85%
Green & Blacks Organic Dark Chocolate 85%
Theo Sea Salt 70%
Tips for mitigating heavy metals found in chocolate:
Making sure you have adequate amounts of iron, zinc, magnesium, and calcium in your diet will reduce the absorption of heavy metals.
For most of us, our liver and kidneys are generally able to rid the body of excess metals. Sweating through exercise or sauna use can also aid in the detoxification process.
In short, if you are not consuming excessive amounts of chocolate, there should be little to worry about with periodic exposure. If, like me, you are an avid consumer of dark chocolate, it may be time to restock your pantry with the varieties with the least amounts of cadmium.