Researchers have revealed that increased consumption of flavanols - a group of molecules which occur naturally in fruit and vegetables - can increase your mental agility.
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.
The study, published in the journal Scientific Reports, Sciences found that 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.
"We used cocoa in our experiment, but flavanols are extremely common in a wide range of fruit and vegetables," said study lead author Catarina Rendeiro from the University of Birmingham in the UK.
"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," Rendeiro added.
In the study, 18 healthy male participants aged between 18 and 40 underwent a standard procedure to challenge the brain's blood circulation that involves breathing five per cent carbon dioxide - about 100 times the normal concentration in air, producing an effect called hypercapnia.
Non-invasive near-infrared spectroscopy, a technique that uses light 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.
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.
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 per cent 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," Rendeiro noted.