The popular treat has a host of impressive health benefits, but not all bars are created equal
By Sue Quinn
The ancient people of what is now Peru knew a good thing when they tasted it. More than 5,000 years ago they were sipping cacao, the purest form of chocolate – centuries before it found its way across the oceans to sweeten life in Europe. Today, chocolate is one of the most popular treats on the planet: in the UK alone, it’s thought that, as a nation, we now chomp through at least 4.5kg per person each year.
And, although it still accounts for a relatively small slice of the UK’s £6.4 billion chocolate market (seven per cent), dark chocolate’s popularity, in particular, is soaring. Sales reportedly jumped 21.5 per cent over the past year, according to NielsenIQ, which is more than double the growth rate of the market as a whole.
Public-health messaging urging us to curb sugar intake partly explains this shift to darker, less sweet bars. Nutrition experts have also been pointing to dark chocolate’s fibre content and beneficial plant compounds.
The problem is that not all dark chocolate is created equal. “The biggest issue is that dark chocolate is frequently discussed as a single, uniform product, when in fact it varies enormously depending on cocoa content and, crucially, how it has been processed,” says Sarah Berry, a professor of nutritional sciences at King’s College London and chief scientist at nutrition company Zoe.
What is dark chocolate?
In the UK, dark chocolate refers to bars containing more than 35 per cent cocoa solids – the figure usually displayed on the wrapper. This percentage tells you how much of the bar comes from cocoa beans, including any extra cocoa butter the maker has added.
A 70 per cent bar, for example, means 70 per cent of its weight comes from cocoa solids and cocoa butter (cocoa being the roasted, processed form of cacao). The remaining 30 per cent is typically sugar, plus small quantities of other ingredients such as vanilla or emulsifiers. Dark chocolate can also contain a small amount of milk powder, meaning it is not always suitable for vegans.
Generally, the higher the cocoa content, the less sugar a bar contains, and the more bitter it tastes. At the same time, higher cocoa levels can also mean more cocoa butter and therefore more saturated fat.
The health benefits of dark chocolate
In the UK, chocolate containing more than 35 per cent cocoa solids is classed as dark
Rich in antioxidants
Dark chocolate is often grouped with foods like green tea and red wine because of its polyphenol content – plant compounds that can help protect against chronic diseases. A subgroup of these, called flavanols, is thought to be especially beneficial.
They act as antioxidants, helping to protect cells from damage, and have anti-inflammatory effects. In cocoa, they have also been associated with improvements in insulin sensitivity, which, in turn, can help with weight management and energy levels.
Boosts brain health
Prof Berry says some of the strongest evidence links cocoa flavanols to improved blood-vessel function, as they help blood vessels relax and widen, which helps deliver nutrients to the brain. “This combination has been linked to modest improvements in blood flow, blood pressure and, in some cases, even memory,” she says.
Many studies have linked the cocao flavanols with improved brain function, while a 2021 clinical trial found that cocoa supplements may improve performance on a specific memory task for older adults.
Helps protect the heart
Despite its saturated fat content, dark chocolate has been linked to improved heart health. A 2019 meta-analysis found that eating 45g of dark chocolate per week reduced the risk of heart and circulatory diseases, though noted that eating large amounts negated any health benefits.
As Prof Berry notes, this is likely a result of their flavanol content, which helps improve blood flow and pressure, thus relieving stress on the heart.Good for your gut
Many people are surprised to learn that dark chocolate contains fibre, a nutrient that increases good bacteria in the gut and helps lower the risk of inflammation and heart disease.
“Around two to three squares of good-quality dark chocolate – 20g to 30g – may provide [up to] 3.5g of fibre,” says Alex Ruani, a doctoral researcher at University College London and chief science educator at The Health Sciences Academy. “While dark chocolate isn’t a major source, it can still make a modest contribution towards the recommended 30g a day.”
Meanwhile, the cacao flavonols in dark chocolate also act as prebiotics – beneficial compounds that help boost good bacterias in the gut.
