Drinking cocoa may give your brain a major boost of speed and accuracy, according to new research from the University of Birmingham. Study participants who drank cocoa with high levels of flavanols were able to complete complex cognitive tasks much more efficiently.
Flavanols are plant nutrients that are found in tea, grapes, tomatoes, and many other foods, but they are particularly concentrated in the cacao beans that are used to make cocoa. Previous studies have shown that cocoa flavanols can help lower blood pressure, improve blood circulation, and fight cell damage.
The Birmingham team set out to investigate the cognitive effects of cocoa flavanols in young, healthy individuals while focusing on a link between blood oxygenation and cognitive benefits. The researchers used non-invasive brain imaging to measure blood oxygenation levels among individuals who consumed cocoa that contained either high levels of flavanols or no flavanols.
In collaboration with scientists at the University of Illinois, the experts showed that participants who consumed a flavanol-rich drink produced a faster and greater increase in blood oxygenation levels in response to artificially elevated levels of CO2.
Approximately two hours after drinking the cocoa, the volunteers were exposed to air with 5 percent carbon dioxide, which is about 100 times the normal concentration. This is a standard method for challenging brain vasculature to determine how well it responds, said study co-author Professor Gabriele Gratton. He explained that the body typically reacts by increasing blood flow to the brain. “This brings in more oxygen and also allows the brain to eliminate more carbon dioxide.”
The researchers found that most of the individuals had a stronger and faster brain oxygenation response after the consumption of cocoa flavanols. “The levels of maximal oxygenation were more than three times higher in the high-flavanol cocoa versus the low-flavanol cocoa, and the oxygenation response was about one minute faster,” said study lead author Dr. Catarina Rendeiro.
After the carbon dioxide test, the participants were assigned progressively complex cognitive tests, which often required them to manage contradictory or competing demands. During the tests, the researchers found that volunteers who consumed flavanols executed tasks with significantly higher speed and accuracy.
“Our results showed a clear benefit for the participants taking the flavanol-enriched drink – but only when the task became sufficiently complicated,” said Dr. Rendeiro. “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 experts discovered that a small group of four volunteers did not benefit from the flavanol-enriched drink in terms of blood oxygenation levels, and also did not experience any cognitive benefits. These individuals had high levels of brain oxygenation responses at the beginning of the trial that were not influenced by the enriched cocoa.
“Because these four participants already had the highest oxygenation responses at baseline, this may indicate that those who are already quite fit have little room for improvement,” said Dr. Rendeiro. “Overall, the findings suggest that the improvements in vascular activity after exposure to flavanols are connected to the improvement in cognitive function.”
“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.”
The study is published in the journal Scientific Reports.