Could cocoa improve cognitive function?

By Sarah MooreReviewed by Emily Henderson, B.Sc.Nov 24 2020

New findings suggest that the flavanols found in cocoa and other food and drink may enhance cognitive functioning.

Image Credit: Fascinadora/Shutterstock.com

While the health benefits of flavanols on cardiovascular health have been long understood, the new study, conducted at Birmingham University, UK, is the first to demonstrate a link between flavanols consumption and increased mental agility in healthy, young participants.

The numerous health benefits of flavanols

For several decades, scientists have been interested in the potential health benefits offered by the consumption of food and beverages containing flavonoids. The findings of various research projects have suggested the preventative role of flavonoids, with studies demonstrating their potential function in the prevention of heart disease, stroke, and dementia.

Flavanols, which represent a sub-group of flavonoids, are molecules that naturally occur in foods such as apples, berries, cocoa, grapes, and tea. While a wide body of research has established their role in promoting cardiovascular health, little evidence has been obtained to demonstrate the impact of flavanol consumption on brain function.

This month, a research team at the University of Birmingham published the results of their new study in the journal Scientific Reports which furthers our understanding of the health benefits of consuming foods with high levels of flavanols.

The impact of flavonols on cognitive function

The study's researchers recruited 18 men of ages ranging from 18 to 40 years to participate in the research. The research team used two measures of cognitive functioning. They measured blood oxygenation in the brain's frontal cortex, as well as performance on complex cognitive tests.

All participants were asked to breathe in air that contained a concentration of 5% carbon dioxide,  a standard procedure to induce hypercapnia where the brain's blood circulation is challenged. Researchers used non-invasive near-infrared spectroscopy to measure the changes in blood oxygenation levels, allowing them to monitor changes in oxygenation in the blood of the frontal cortex following the induction of hypercapnia.

Following breathing in the carbon dioxide-rich air, the participants were asked to complete a range of cognitive tasks that became increasingly complex. Participants completed cognitive tests on four occasions. Before and after drinking a cocoa drink that was enriched with flavanols, and before and after drinking a regular cocoa drink.

The study's results showed that following the consumption of the flavonol-enriched cocoa drink, participants' blood oxygenation in response to hypercapnia was roughly three times the levels observed following consumption of the non-flavonol-enriched cocoa drink. These heightened levels following consumption of the enriched drink were also reached up to one minute faster than the peaks seen in those who drank the non-enriched drink.

The results of the cognitive tests demonstrated that after drinking the enriched drink, participants were able to complete tasks with greater speed and accuracy, with the men completing the tasks an average of 11% faster.

Increased brain blood oxygenation and cognitive ability

The study's results show that consumption of flavonols can improve cognitive function when the brain is required to complete sufficiently complicated tasks.

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".

Dr. Catarina Rendeiro

Interestingly, the researchers observed that for a small portion of the participants, no benefit from drinking the flavanol-enriched drink was obtained.

Data collected via non-invasive near-infrared spectroscopy revealed that this group already had high levels of brain oxygenation responses, therefore, were unlikely to benefit from increasing these further. This additional evidence helps support the link demonstrated between increased brain blood oxygenation and cognitive ability.