Let’s face it, I’m a chocoholic. So, when it came to exploring the science of cocoa products, I was bound to be a bit biased. But as I fought my urge to cherry pick research supporting the health benefits of cocoa, I came to see that it really is highly nutritious. However, there’s also a dark side to cocoa (pun intended) that has implications for which cocoa products you should pick. In the next couple of blogs, I’m going to highlight the science of cocoa, beginning with how cocoa affects brain health and the best ways to consume cocoa for maximum benefits.
If you struggle to focus at work, find it hard to remember where you put your keys, or feel tongue tied as you struggle to find the right word, I think you'll find today's post helpful!
Before we get going, I just want to clarify something: When I refer to cocoa, I’m referring to what some would call cocoa and others would call cacao. Both come from the cocoa plant, Theobroma cacao. And although cocoa is technically cacao processed into a powder, most people use cocoa and cacao interchangeably. So, let’s not get our knickers in a terminology twist. Onwards!
- Cocoa contains many bioactive substances and is particularly rich in methylxanthines (theobromine, theophylline, caffeine) and flavanols (of which epicatechin is the most important).
- Regular cocoa flavanol intake boosts the formation of new blood vessels and bloodflow in brain regions involved in learning and memory.
- 250 to 1,000 mg cocoa flavanols per day can improve certain aspects of mood and cognition (e.g., attention and working memory). Doses in the upper end of this range tend to have larger effects.
- Cocoa from Latin America tends to be high in cadmium, a toxic metal that accumulates in the body, so it’s generally best to opt for cocoa from Africa.
- Alkalisation (“Dutching”) improves several sensory characteristics of cocoa but reduces some health-promoting substances in it (e.g., flavanols). Choose natural or lightly-alkalised cocoa powders (pH up to 7.2).
- Due to their methylxanthine contents, cocoa-rich products are quite stimulatory, so it’s best to have them in the first half of your waking day.
The composition of cocoa
Cocoa beans contain many bioactive substances, each of which likely contributes to certain effects on health. Cocoa is rougly 40 to 50% fat by weight, most of which is saturated and monounsaturated. This fat is sometimes made into cocoa butter and helps give chocolate its structural integrity and killer mouthfeel.
Cocoa also contains nitrogenous substances, including protein and “methylxanthines”. Caffeine is the most exalted methylxanthine, but cocoa has more theophylline than caffeine, and yet more theobromine than theophylline. These methylxanthines contribute to cocoa’s bitter taste and stimulating effects – more on this later.
Then there’s the carbohydrate in cocoa. Cocoa is very high in fibre, nondigestible carbohydrate that contributes to feelings of fullness and cocoa’s effects on gut health.
And while cocoa contains small amounts of some vitamins (e.g., B vitamins) and is quite rich in several minerals (especially iron and magnesium), it’s cocoa’s polyphenols that steal the show. More specifically, cocoa contains about the highest flavanol content of any plant per unit dry mass, and some of these flavanols (epicatechin, in particular) potently affect key aspects of health, including brain function.
Regular cocoa intake bolsters brain health in elderly people
I first became interested in the science of cocoa when I noticed that eating dark chocolate or drinking cocoa seemed to sharpen my mind and lift my mood. It turns out there’s something to this.
There have now been many studies assessing the effects of consuming cocoa flavanols on brain structure and function. Much of this work has included elderly participants, for cognitive decline can be hugely debilitating, and it’s easier to identify effects on brain function when a person’s cognition is past its best. This research has shown that regularly consuming doses of 250 to 993 mg cocoa flavanols per day enhances various dimensions of cognition, including attention and processing speed during visual tasks, working memory, and verbal fluency (how easy it is to bring words to mind).
These actions of long-term flavonol intake are in part due to flavanols and their metabolites aiding the formation of new blood vessels (angiogenesis) in brain regions involved in learning and memory (e.g., the hippocampus). Going by the effects of flavanol intake on brain bloodflow, it seems likely that cocoa’s brain-boosting benefits are most prominent in people with suboptimal brain bloodflow. Given the current state of our population’s cardiovascular health, this means lots of us stand to benefit from cocoa’s effects on the brain!
Single doses of cocoa sharpen the minds of youngsters too
You don’t have to consume cocoa every day or be over 65 to get a cerebral advantage from cocoa. When given single doses of 250 to 994 mg cocoa flavanols, young adults experience a similar range of positive cognitive consequences (e.g., improved alertness and working memory).
As is true of many so-called “nootropics” (substances that enhance brain health and function in both the short and long term), there are reasons to think that cocoa is especially helpful when the brain is working hard - when doing tasks that are very cognitively demanding, for instance. Related to this, one of the more interesting relevant studies had participants eat either a low-flavanol chocolate bar (89 mg cocoa flavanols) or a high-flavanol one (520 mg cocoa flavanols) after a night without any sleep, a condition that compromises brain state. Eating the high-flavanol chocolate offset the blood-pressure raising and bloodflow-impairing effects of sleep deprivation, and by normalising bloodflow, flavanols helped preserve memory, at least in women. So, cocoa seems like a good choice if you’re short on shuteye.
More recent research has shown that eating a bar of flavanol-rich chocolate sharpens some aspects of vision too, which is helpful if you’re even a quarter as blind as I am.
Overall, these studies of brain function tend to show that dose does matter, with higher doses having greater positive effects. It seems that a dose of 250 to 1,000 mg cocoa flavanols per day can boost brain health, and if you want to maximise this response, I’d favour the upper end of this range.
How cocoa affects brain health: it’s not all about bloodflow
While we don’t fully understand what cocoa flavanols are doing in the brain, changes in bloodflow are probably not the whole story. Within the brain, flavanols also appear to have neuroprotective effects, stimulating pathways involved in the survival of neurons and the formation of memories. This could be transformative for the ageing brain.
One thing to note is that some of these studies assessed effects of isolated cocoa flavanols, but other cocoa products (e.g., cocoa powder) are rich in additional chemicals that affect brain function, such as caffeine and theobromine. This is important, for some research has shown that cocoa’s caffeine and theobromine contents might underlie cocoa’s immediate effects on brain function.
I’ve previously written at length about caffeine (see this post), so I won’t retread that ground. You might not be so familiar with theobromine though. Chemically, theobromine is just caffeine with an additional methyl group, so it shares some of caffeine’s properties – both, for example, block the interaction of a sleep-promoting chemical (adenosine) with its receptors. However, theobromine is roughly a fifth as stimulatory as caffeine and is absorbed and metabolised more slowly. Its stimulatory effects are also a little different from caffeine in that theobromine seems to increase heart rate more than caffeine, whereas caffeine is more stimulatory in the brain. And unlike caffeine, theobromine promotes blood vessel dilation and hence slightly reduces blood pressure. It therefore seems likely that caffeine and theobromine have some complementary stimulatory effects.
And then there are the other phytochemicals in cocoa that might influence the brain. As there are certain lipids in cocoa that are similar to chemicals in cannabis, some speculate that these lipids might bind to cannabinoid receptors in the brain and thereby influence mood and more. While I’m not convinced the concentrations of these substances are sufficient to have any discernible actions, there is certainly evidence that polyphenol-rich cocoa can boost mood. And when you do consume cocoa products, be sure to do so mindfully, for it seems that how mindfully you consume cocoa products determines how much they raise your spirits!
Considerations when sourcing cocoa products: pay attention to cadmium!
As is true of other plants, cocoa’s composition depends on its genetics and environmental exposures. As just one example of this, African cocoa tends to contain more theobromine than Latin American cocoa. While this particular difference isn’t hugely important, where you get your cocoa from might meaningfully influence how cocoa affects your health. The reason is that some cocoa has worrying amounts of aluminium, cadmium, and lead. And if I were you, I’d pay particular attention to cadmium, for cocoa powder can be very high in cadmium relative to other foods.
Our bodies are rubbish at getting rid of cadmium we consume (its half life is probably between 10 to 30 years), meaning that we tend to accumulate this metal in our tissues. Over time, this can lead to very serious health problems, including brittle bones, kidney toxicity, and cancer. Not cool.
The good news is that the EU enforced new cadmium regulations in 2019, limiting products to 0.6 mcg per g cocoa powder. Outside of Europe, however, you might want to be more cognizant of where your cocoa is from. As a rule of thumb, pick cocoa products from Africa. Some cocoa snobs consider Latin American cocoa the pick of the gastronomic bunch, but it tends to contain much more cadmium than African cocoa. Needless to say, at Resilient Nutrition, we only use West African cocoa in our chocolate-flavour products.
There are other things you can do to reduce your cadmium intake from cocoa. As cadmium competes with fellow minerals for uptake, combining cocoa with foods or drinks high in minerals (e.g., calcium, zinc, iron) can help reduce cadmium uptake, so mixing cocoa products with dairy does make some sense.
One for cocoa powder lovers: shall we go Dutch?
One other consideration that might be on your mind is whether to pick alkalised (“Dutched”) cocoa products. This is itself a subject that could span many blogs, so I’ll give you the brief lowdown.
Alkalisation involves mixing cocoa with an alkali solution (e.g., sodium hydroxide) and heating and pressurising the mix. This makes cocoa less acidic, darkens it, and improves how it dissolves in water. So, natural cocoa is slightly acidic and light brown, strongly alkalised cocoa is almost black and slightly alkali (Oreos contain heavily alkalised cocoa), and slightly alkalised cocoas have the enticing sensory combination of a deep brown colour and rich, chocolatey taste.
The key tradeoff, however, is that alkalisation reduces methylaxanthine and flavanol contents and tends to transform (“isomerise”) epicatechin, the most bioavailable flavanol, to catechin. There are also other changes that take place during alkalisation, some good (e.g., reduced mycotoxins, which are toxic metabolites produced by moulds), some bad (e.g., increased Maillard reaction products, which can be toxic at high doses).
So, if you’re trying to sharpen your mind by increasing your flavanol and methylxanthine intake, pick a natural or lightly alkalised cocoa powder (pH up to 7.2, perhaps).
Which cocoa products are best?
By now, you might want some cocoa product recommendations, so here are some of my favourites:
- Chocolate: My favourite is Montezuma’s Absolute Black, made from 100% cocoa (the mint one and orange one rock). Going by an independent analysis by ConsumerLab, this product has about 350 mg cocoa flavanols per 25 g (that’s a HUGE amount for chocolate) and is very low in cadmium. This is a much better profile than the other chocolates ConsumerLab tested. Please note that it’s high in caffeine and theobromine too (85 mg caffeine and 605 mg theobromine per 25 g). If Absolute Black is too bitter for you, I also love Green & Black’s Velvet Edition bars, which contain 70% cocoa chocolate. They’re made with Ghanaian cocoa and are phenomenally tasty, at least to my tastebuds.
- Cocoa powder: Barry Callebaut produces a range of delicious cocoa powders. My favourites include Acticoa, a natural cocoa that is exceptionally flavanol rich (8.3% flavanols, on average). It’s been well studied, but it’s hard to track down and is not the best tasting product. Plein Arôme is also a great product. It’s West African and is slightly alkalised, so it's delicious but still retains many of its flavanols and methylxanthines.
- Flavanol supplements: CocoaVia products are terrific, if you can get your hands on them. Unfortunately they’re very hard to source in the UK.
What is the best time of day to consume cocoa?
Finally, high methylxanthine concentrations make many cocoa products much more stimulating than most people realise. The implication is that it’s probably best to have cocoa products in the first half of your waking day – ideally at least 8 h before bed.
Stimulant content aside, eating chocolate in the morning seems to be better for metabolic health than chocolate in the evening, although please note that participants were given sugar-laden milk chocolate. There's also some fascinating research showing that feeding rats a piece of chocolate at breakfast helps the animals adjust faster to conditions mimicking jet lag and shift work. Could it be that when your body clock is out of sync with the world around you, starting your day with cocoa could help you get back on time? We'll have to wait and see!
That’s all for now. In the meantime, keep your eyes for the next blog, which will explore how cocoa can improve your cardiovascular health, digestion, and more!