Dietary Flavanols Improve Cognitive Performance with Complicated Tasks

Increased consumption of flavanols can increase your mental agility, according to research published today in Scientific Reports in which people given a cocoa drink containing high levels of flavanols were able to complete certain cognitive tasks more efficiently than when drinking a non-flavanol enriched-drink.

Flavanols, a sub-group of plant flavonoids, are present in cocoa, grapes, apples, tea, berries and other foods. They are known to have a beneficial effect on cardiovascular health, but their effects on brain health are not well understood.

In the new study, 18 healthy male participants aged between 18 and 40 underwent a standard procedure to challenge the brain's blood circulation that involves breathing 5% carbon dioxide—about 100 times the normal concentration in air, producing an effect called hypercapnia. Non-invasive near-infrared spectroscopy was used to track the increases in brain oxygenation in the frontal cortex in response to this carbon dioxide challenge.

Each participant underwent the test before and after drinking a cocoa drink on two occasions and on one of those occasions, the drink was enriched with flavanols. Following the carbon dioxide test, the participants were asked to complete a number of progressively complex cognitive tests. The 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 three times higher than participants drinking the non-flavanol-enriched drink. They also achieved these elevated levels one 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.

"Our results showed a clear benefit for the participants taking the flavanol-enriched drink—but only when the task became sufficiently complicated," explains lead author Catarina 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."