Healthy Ingredients
The truth about dark chocolate and heavy metals
Our founder, Liz Earle, reveals some of the surprising health benefits of chocolate – and explains what she thinks about recent research linking dark chocolate and heavy metals…
Did you know that dark chocolate is actually the richest plant source of health-giving polyphenols?
These plant chemicals protect our cells from inflammation, improve brain function and support our immune and cardiovascular health. It’s positively medicinal!
Chocolate (or, more specifically, cacao, the pod that’s ground into powder) contains theobromine, similar to caffeine in that it gives us a lift, enhances mood and makes us feel more alert.
A meta-analysis published in the American Journal of Clinical Nutrition shows chocolate and cacao can help to improve heart health, lower blood pressure and improve insulin regulation, with researchers concluding: ‘We found consistent acute and chronic benefits of chocolate or cocoa […] with no suggestion of negative effects.’
Chocolate and longevity
As well as being a healthy, sweet snack, evidence is emerging that we should eat chocolate for pro-ageing and longevity too. Studies published in 2022 show that cacao assists apoptosis (the recycling of old cells), improves mitochondrial activity and rejuvenates senescent cells.
Cacao has also been shown to help regulate gene expression, downregulating troublesome genetic ‘snips’ or variances. One study even found it effective at reducing presbycusis, or age-related hearing loss (which currently has no effective treatment).
Cacao also contains epicatechin, a compound linked to angiogenesis, the body’s process of stem-cell regeneration. A study by researchers in California demonstrated that epicatechin-rich cocoa significantly increased capillary density (in rats, but, these studies can be relevant to humans) after just two weeks.
This increase was due to a rise in stem-cell production, enabling tissues to repair themselves more quickly and effectively. So taking dark chocolate on hospital visits post-surgery is clinically a very good idea.
Not just for repair work, though – the process of angiogenesis is critical throughout our lifespan, especially when it comes to ageing. By increasing blood-vessel growth, nutrients can be delivered more effectively around the body, and waste matter and toxic cell debris more easily removed. This, in turn, improves overall cell functioning, reduces inflammation and can help with pain management too.
Raw cacao beans also contain powerful antioxidant phenolic compounds (notably procyanidins) that reduce the oxidative stress that damages cells, leading to ageing and degenerative diseases, such as Alzheimer’s.
A better quality of life
Cacao also stimulates endorphins, those happy chemicals in the brain that are also analgesic, so help lower pain and can even improve our quality of sleep (just don’t eat dark chocolate close to bedtime as its caffeine content can keep you awake).
So, there’s nothing intrinsically ‘bad’ about chocolate, it’s more the extra ingredients we find in it that are troublesome. I buy plain cacao nibs and keep a stash of these in my kitchen for when I feel like grabbing something sweet – they’re high in fibre and give us a healthy shot of antioxidants as well as satisfying a craving for something sweet.
I eat a few of these plain, sprinkled into yoghurt or with a teaspoonful of nut butter for an instant Snickers bar-style bite.
How to choose the best chocolate
Of course, you can also choose a chocolate bar and, here, the key is to look for the percentage of cocoa solids it contains. The higher the percentage, the less room there is for added sugars and other ingredients, including fats such as palm oil.
I used to not like dark chocolate, having been brought up with the traditional milk chocolate bars and the kind of ‘junk’ bars we find in brightly coloured plastic wrappers to tempt us at the supermarket checkout or petrol station. However, it is possible to wean yourself off the sweeter stuff in stages.
If you’re a chocoholic who doesn’t like dark varieties, try scaling up the percentage of cocoa each time you buy, gradually getting used to a slightly more bitter taste. I now find milk chocolate far too sweet and will always choose a darker option out of preference, buying some of the more niche brands that can be over 90 per cent cocoa, or even 100 per cent pure chocolate.
A side benefit of these darker blends is that it’s almost impossible to overeat, as one or two squares are all it takes to satisfy the sweetest tooth. Just keep in mind that all chocolate, especially the darker kinds, are high in caffeine. For this reason, I tend not to eat any after mid-afternoon and never after dinner.
Before buying any chocolate, it’s worth checking the amount of sugar listed on the label. A simple switch can make a big difference in terms of reducing our sugar load. Alas, sugar levels in confectionery have sharply risen over the years, increasing on average by 23% between 1992 and 2017.
What’s the deal with heavy metals?
Set against all the good news and health benefits, a darker cloud has loomed large over some chocolate brands. Worrying studies surfaced in 2022 reporting traces of heavy metals, notably cadmium and lead, in dark chocolate, so how concerned should we be?
Researchers from Consumer Reports, a US non-profit consumer organisation, measured heavy metals in 28 popular dark chocolate bars – and found cadmium and lead in all of them, including Godiva, Hershey’s, Green & Black’s, Lily’s and Lindt. Even organic, ethical, vegan and sustainably sourced brands were not exempt from their findings.
The only brands readily available in the UK found to contain below California’s maximum acceptable dosage levels were Ghirardelli and Valrhona. Dark chocolate fared worse than milk chocolate simply because it has a higher content of pure cocoa solids.
Before ditching dark chocolate altogether, it’s important to firstly remember that all plant foods tend to contain traces of heavy metals, depending on the soil they’ve been grown in.
Chocolate is no exception. Cacao plants take up cadmium from the soil with the metal building up as the pod grows. Lead enters the food chain another way and seems to get into the cacao after the beans have been harvested, indicating it is more to do with the harvesting, drying and storage practices (and so is less linked to increased percentages in the cacao).
Liz’s verdict
So do I still eat dark chocolate? Yes I do, especially for its pro-ageing and cell-protecting benefits, but I limit myself to just a few squares a day – and I check online for updated information from my favourite brands.
Until we’re clearer on the action taken by manufacturers to reduce heavy metals, I suggest this is the most prudent action for chocolate-lovers – enjoy modest amounts (although children and pregnant women should probably limit their intake).
Don’t forget that cacao has been shown to be cellularly protective and we can also compensate by making sure our diets include other nutrients that protect us against heavy-metal harm, such as calcium, iron, selenium, glutathione, vitamin C and zinc.
Extracted from A Better Second Half, by Liz Earle
