Last Updated on August 19, 2021 by Nick Baskett

Research conducted by University of Birmingham, working with experts at the University of Illinois at Urbana-Champaign (Illinois), published in Scientific Reports suggests drinking cocoa increases mental acuity, at least for a time!

Cocoa contains flavonals, a sub-group of plant flavonoids and when consumption is increased, can increase mental agility, according to new research.

A team of researchers at the University of Birmingham found that people who consumed a cocoa drink which contains high levels of flavonols were able to complete assigned cognitive tasks more efficiently than subjects drinking a non-flavanol enriched drink.

The subjects also underwent non-invasive brain imaging to measure blood oxygenation levels in the brain.

Working with experts at the University of Illinois at Urbana-Champaign (Illinois), the researchers showed that participants who had consumed the flavanol-rich drink produced a faster and greater increase in blood oxygenation levels in response to artificially elevated levels of CO2 (hypercapnia).

Lead author, Dr Catarina Rendeiro, of the University of Birmingham’s School of Sport, Exercise and Rehabilitation Sciences, explains:

We used cocoa in our experiment, but flavanols are extremely common in a wide range of fruit and vegetables. By better understanding the cognitive benefits of eating these food groups, as well as the wider cardiovascular benefits, we can offer improved guidance to people about how to make the most of their dietary choices.


18 healthy male participants aged between 18 and 40 took part in a standard procedure, and observed the brains’ response when it was put under pressure.

They achieved this by inhibiting the blood circulation to the brain by getting the test subjects to breath a mixture with 5% carbon dioxide – a number about 100 times the regular concentration.

This creates a condition or effect, called hypercapnia. Non-invasive near-infrared spectroscopy – basically shining a special light through the skin to capture changes in blood oxygenation levels, was used to track the increases in brain oxygenation in the frontal cortex in response to this carbon dioxide challenge. This sounds similar to technology some smart watches used to identify oxygen levels when worn on your wrists.

Each participant took the test before and after drinking a cocoa drink on two occasions and on one of those occasions, the drink was further enriched with flavanols. Following the carbon dioxide test, the participants were asked to complete a number of progressively complex cognitive tests.


Researchers found that the participants who had taken the flavanol-enriched drink had the highest levels of blood oxygenation in response to hypercapnia, reaching levels up to 3 times higher than participants drinking the non-flavanol-enriched drink. They also achieved these elevated levels 1 minute faster than participants who drank the non-enriched cocoa.

In the cognitive tests, the researchers found significant differences in the speed and accuracy with which volunteers completed the higher complexity tasks, with volunteers who had taken the flavanol-enriched drink performing the tasks 11% faster on average.

Dr Rendeiro explains,

Our results showed a clear benefit for the participants taking the flavanol-enriched drink – but only when the task became sufficiently complicated.

We can link this with our results on improved blood oxygenation – if you’re being challenged more, your brain needs improved blood oxygen levels to manage that challenge. It also further suggests that flavanols might be particularly beneficial during cognitively demanding tasks.

The researchers also noted a further outcome. Within the study cohort, there was a small group who did not benefit at all from the flavanol-enriched drink in terms of blood oxygenation levels, and who also did not derive any cognitive benefit.

This group evidently had existing high levels of brain oxygenation responses to start with that were not increased further by drinking the enriched cocoa.

Dr. Rendeiro concluded,

This may indicate that some individuals, that perhaps are already very fit, have little room for further improvement.

The small group of participants who did not react to the flavanol gives us additional evidence to confirm the link between increased brain blood oxygenation and cognitive ability,

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