The hidden health benefits of dark chocolate – fact or fiction?

Is dark chocolate good for you? And could snacking on a square or two actually be OK for your health? 

We delve deeper to find out more about dark chocolate benefits and the new research behind the chemical theobromine, a natural cocoa compound, that could potentially have pro-ageing properties.

While chocolate is known for being high in fat and sugar, the higher cocoa content of dark chocolate means it could also have some health benefits. 

We spoke to Which? nutrition expert Shefalee Loth about dark chocolate health claims and asked her to separate fact from fiction. Keep reading to find out which claims are worth paying attention to, plus how to choose lower-sugar options.

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Dark chocolate health benefits

Dark chocolate typically contains cocoa, sugar and added flavourings, for example vanilla. 

In the UK, the minimum required cocoa content for dark chocolate to be labelled as such is 35%, but most dark chocolate contains a much higher proportion of cocoa – 70% cocoa bars are one of the most widely available options. 

While it's considered to have some health benefits, dark chocolate is still high in calories and fat, so it's best eaten in moderation.

Benefits include:

Source of antioxidants

Cocoa is rich in polyphenols, a type of antioxidant that's been linked to a range of cardiovascular, brain and gut health benefits.

However, bear in mind that dark chocolate may only contain small amounts of antioxidants, as most are removed in the manufacturing process.

Eating plenty of fruit and vegetables is a better way to boost antioxidants in your diet.

Source of minerals 

As well as polyphenols, dark chocolate is also rich in essential minerals, including magnesium, iron and zinc.  

These play an important role in supporting your overall health, and can help to boost immunity and aid energy production, bone health and more. 

However, as with antioxidants, chocolate shouldn't be your main source of minerals. You'll also find them in cereals, bread, meat, fish, milk, nuts, fruit and veg.

Lower in sugar

Dark chocolate with a high cocoa percentage is often highlighted as a good low-sugar option for satisfying sweet treat cravings. 

A standard 20g serving (around two squares) typically contains around 5-6g of sugar, which is less than some other sugary snack alternatives. It's worth checking the label though, as many bars are still classed as high in sugar (more than 22.5g of total sugars per 100g).

Is dark chocolate high in fibre?

A diet that's rich in fibre has been associated with a number of health benefits, including a lower risk of heart disease and stroke.

Fibre content is often touted as a benefit of dark chocolate, but again the actual amount in one serving is relatively small (sorry!).

A standard 20g serving (around two squares) of 70% dark chocolate usually has around 2g of fibre, which works out at only 7% of the daily recommended amount (30g). Bars with a higher percentage of cocoa solids will usually have a higher fibre content.

Every little helps, but if you're trying to get more fibre in your diet then eating more wholegrains, pulses, fruit and vegetables is a better bet.

Dark vs milk chocolate: what's the difference?

Dark chocolate can be a healthier option compared to milk chocolate, especially if you're trying to cut down your sugar consumption.

The table below shows how the calories, fat and sugar content per 100g compares for Lindt dark chocolate with 70% cocoa and a Lindt milk chocolate bar.

While the calorie and fat content is similar, Lindt's dark chocolate bar is much lower in sugar (29g) compared to the milk chocolate bar (50g). Some of this sugar will be from milk (in the form of lactose). However, both still get a red traffic light rating overall for sugar.

Could a key chemical in dark chocolate slow down ageing?

Another benefit of dark chocolate has recently been in the news, as a result of new research published from King's College London. It suggests that the chemical theobromine, a natural cocoa compound, could potentially have anti-ageing properties.

So could eating dark chocolate help us stay younger for longer? 

The people who took part in the research who had higher theobromine circulating in their blood had a biological age that was lower than their actual age. However, those involved in the study stress that you also have to remember dark chocolate contains sugar, fat and other compounds, and more research must be done. 

Professor Jordana Bell, senior author of the paper and a Professor in Epigenomics at King’s College London said: 'Our study finds links between a key component of dark chocolate and staying younger for longer. While we’re not saying that people should eat more dark chocolate, this research can help us understand how everyday foods may hold clues to healthier, longer lives.'

How to buy more sustainable chocolate – we unpack the ethical and sustainability issues associated with cocoa production, and tell you which certifications to look for

How to choose healthier chocolate

Here are some key things to consider if you're looking for a healthier bar of chocolate:

• Cocoa percentage The amount of cocoa in dark chocolate can range from 35% all the way up to 100%. Choosing a higher percentage bar with more cocoa solids is likely to be higher in fibre and minerals, and lower in sugar.
• Sugar content Although less sugary than milk chocolate, some dark chocolate bars are still high in sugar, so it's worth checking the label carefully and avoiding those with a red traffic light.
• Added ingredients Bars often have extra flavourings and ingredients, which can dramatically increase the fat and sugar content. Try to stick with minimally processed and high quality chocolate where possible.

What is raw chocolate? And is raw chocolate better for you?

Raw chocolate has often been referred to as a 'superfood' as it can contain more nutrients such as iron, zinc, magnesium and vitamin C. When cocoa is usually roasted and exposed to high oven temperatures, you lose some of these nutrients. However, the raw chocolate version is a type of chocolate that has been made from unroasted cacao beans, meaning the beans have not been heated to high temperatures. 

Founder at JOYÀ and chef, Ruth Elnekave, explains: 'Many argue that chocolate cannot truly be considered 'raw' (labelling it as such can be misleading), because key steps in chocolate processing—fermenting cacao beans, grinding them into a paste, and tempering—exceed the generally accepted 'raw' food temperature of 40–48°C (104–118°F). For this reason, many experts and manufacturers prefer the term 'unroasted,' as chocolate can be made without roasting the beans.

All chocolate loses some nutrients during manufacturing, but more remain intact in unroasted chocolate than in chocolate that has been roasted.

It's good to note though, regarding sugar (including coconut sugar): unroasted chocolate does not necessarily contain less sugar than roasted chocolate. Sugar levels vary by manufacturer to achieve the desired flavour, so check the nutrition label if sugar is a concern.'

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Shefalee Loth is a public health nutritionist with 20 years' experience working at Which?, the NHS and in research at The London School of Hygiene & Tropical Medicine and World Cancer Research Fund. At Which? Shefalee is a principal researcher, researching and writing food and nutrition content for our magazine and website and is a media spokesperson. She is a trustee at Sustain, the food and farming alliance.