The foods can even restore memory in older people.
Flavanols, which naturally occur in fruit and vegetables, can make you smarter, new research finds.
People who consumed a cocoa drink laced with flavanols performed 11 percent faster on complex cognitive tests than those given a placebo.
Flavanols work by increasing blood oxygenation.
Flavanols are present in grapes, cocoa, apples, berries, tea and many other foods.
Dark chocolate is a particularly rich source of cocoa flavanols.
Dr Catarina Rendeiro, study co-author, said:
“Flavanols are small molecules found in many fruits and vegetables, and cocoa, too.
They give fruits and vegetables their bright colors, and they are known to benefit vascular function.
We wanted to know whether flavanols also benefit the brain vasculature, and whether that could have a positive impact on cognitive function.”
The small study included 18 people given either a flavanol-rich drink or a placebo.
Two hours later, brain scans showed that those who had consumed flavanols had blood oxygenation three times higher in response to hypercapnia.
Hypercapnia means the elevation of carbon dioxide in the bloodstream.
Dr Rendeiro explained the results:
“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.”
Long-term flavanol consumption
Taking cocoa flavanols over the long term has also been linked to a variety of mental benefits.
In elderly people, they have been shown to improve cognitive performance, attention, processing speed and verbal fluency.
These effects are particularly strong among elderly people starting to see age-related mental decline.
One study, published in Nature Neuroscience, found a high-flavanol diet could restore aspects of older people’s memory back to that of a typical 30- or 40-year-old.
The study was published in the journal Scientific Reports (Gratton et al., 2020).
