Dark chocolate has long been touted as a healthier choice for people looking to satisfy their sweet tooth without spiking their blood-sugar.
But what the millions of people may not know is that they may also contain heavy metals linked to cancer.
Multiple tests performed by consumer watchdogs have discovered high levels of cadmium and lead in chocolate products, which have been associated with kidney and bone disease, brain damage, miscarriages and tumor growth.
Now Brian Johnson, a 46-year-old biohacker who has claimed to have reversed his biological age by a decade, has analyzed 10 popular dark chocolate bars to find the worst offenders.
All 10 dark chocolate bars contained detectable metals (though Johnson does not specify which metals he tested for) and two products made by Alter Eco were given the worst scores because they had triple the levels of some rival brands.
The scale ranged from zero to 100, with higher scores indicating better products
As well as metal levels, Johnson also tested for flavanols – plant compounds that can improve heart and brain health, help fight cell damage and infection and protect the body from toxins and inflammation.
Based on the amount of flavanols and heavy metals each chocolate bar had, the biohacker, who spends a reported $2million a year on his anti-aging lifestyle, assigned each product a score.
The scale ranged from zero to 100, with lower scores indicating a worse health profile.
Mr Johnson tested 10 popular dark chocolate bars, including Lindt Excellence, Ritter Sport, Beyond Good, Alter Eco, Hu and Tony’s Chocolonely.
They ranged from 70 percent cocoa to 100 percent cacao, with some claiming they were sustainably sourced, good for the environment and free of processed additives.
Of the 10 products, Alter Eco’s 85 percent cacao classic blackout dark chocolate scored the lowest, at 13.
While it had higher levels of flavanols (140.5 mg), it contained 10.6 micrograms of heavy metals.
A second Alter Eco product scored similarly: 100 percent cacao total blackout chocolate, with 210.5 mg of flavanols and 14.7 mcg of heavy metals – giving it a score of 14.
Brian Johnson is a biohacker who claims to have reversed his biological age from 46 years old to 37 years old
The highest-scoring product Mr Johnson tested was Vosges’ 72 percent cacao black salt caramel exotic chocolate bar, which had 159 mg of flavanols and just 2.0 mcg of heavy metals, giving it a score of 78.
Mr Johnson said: ‘What we’ve learned today is several things. One: marketing and packaging mean nothing. It does not matter what they say. It doesn’t matter what words they use, how pretty their pictures are. It does not matter.
‘Second: Not knowing is very dangerous… This is why it’s so important to know what you’re eating and to have quantified data on the cleanliness and on the positive benefits.
‘Transparency in our food supply chain is a good thing for everybody. Nobody wins when our food supply is dirty. Nobody wins when we’re unhealthy. It’s time we change the world from a “die economy” to a “don’t die economy.”‘
There is no federal level set nationwide for exposure to lead and cadmium, but 2017 research determined 62 micrograms (mcg) of cadmium is the highest tolerable level for a 154lb person per day when it comes to kidney health.
While the FDA lists the cadmium tolerability level at 0.21 to 0.36 micrograms of cadmium a day per about 2lbs of body weight – or about 25 micrograms for a 154lb person.
There is no safe level of exposure to lead, but the FDA’s acceptable daily intake of lead in food is 2.2 micrograms for children and about 8.8 micrograms for adults.
California has even stricter safe level recommendations – at no more than 0.5 mcg of lead per day and no more than 4.1mcg of cadmium.
Chocolate may be exposed to heavy metals through cocoa powder, which is used to give bars their velvet chocolate flavor.
Lead may become mixed with cocoa when the beans are laid out by the side of roads to dry and then get covered in car fumes.
Cadmium can be inside the beans when they are picked, because the cacao tree may have drawn it from the soil.
A Tony Chocolonely product scored 37 out of 100
Separate research published in July from George Washington University analyzed 72 commercial cocoa products over eight years, testing them for heavy metals like lead, cadmium, and arsenic.
Researchers found all products contained traces of toxic metals, and almost half had up to 20 percent more than the maximum allowed dose of lead.
More than a third exceeded allowed levels of cadmium, which has been linked to cancer and kidney damage.
The researchers did not disclose which chocolates were tested.
And 2023 research found 16 of 48 chocolates tested — a third — had high levels of lead or cadmium, and every single one contained detectable levels of the metals.
This included Hershey’s milk chocolate bars and hot cocoa mixes from Trader Joe’s, Starbucks and Ghirardelli.
