Mounting evidence demonstrates improved cognitive function from cocoa flavanol consumption

A study just published in the American Journal of Clinical Nutrition (AJCN) adds to the growing body of evidence demonstrating that cognitive function is improved with a diet high in cocoa flavanols

A study just published in the American Journal of Clinical Nutrition (AJCN) adds to the growing body of evidence demonstrating that cognitive function is improved with a diet high in cocoa flavanols — a group of naturally occurring bioactives found in fresh cocoa beans.

It is normal for cognitive function to slightly deteriorate with age. Memory capacity begins to worsen, along with processing speed and the ability to form long-term memories. Finding a way to defer the onset of these issues becomes increasingly important as life expectancy gets longer and global populations age.

This study, conducted by researchers from Italy’s University of L’Aquila and Mars, Incorporated, reinforces the results of several recent cognitive studies — throwing more light on the important role diet plays in maintaining cognitive health. Dr Giovambattista Desideri, lead author on the paper, said: 'The results of this study are encouraging — they support the idea that diet, and specifically a diet rich in cocoa flavanols, can play an important role in maintaining cognitive health as we age.'

This study was the second installment in a two-part investigation by this team into the effects cocoa flavanols have on the brain. The first study, published in the journal Hypertension in 2012, found cognitive and cardiometabolic benefits of habitual cocoa flavanol consumption in older adults who had been diagnosed with mild cognitive impairment (MCI). Despite these findings, the question of the benefits of cocoa flavanols on cognitive function among individuals without MCI remained uncertain.

This second study looked to address this question. Enrolling men and women aged 61-85 years with no evidence of cognitive dysfunction, the participants in this controlled, randomised, double-blind study were assigned to one of three flavanol groups, consuming a drink containing either high (993mg), intermediate (520mg) or low (48mg) amounts of cocoa flavanols every day for 8 weeks. The nutritionally matched drinks were specially prepared. The high- and intermediate-flavanol cocoa drinks were produced using Mars’ patented Cocoapro process, while the low-flavanol drink was made with a highly processed, alkalised cocoa powder. Other than the inclusion of the test drink, normal diets and regular lifestyle were maintained throughout the study.

At the start of the study and after 8 weeks, cognitive function was assessed using a battery of tests that examined memory, retention and recall, as well as executive function. Among those individuals who regularly consumed either the high- or intermediate-flavanol drinks, there were significant improvements in overall cognitive function after only 8 weeks. As cognitive function was normal for this aged population, this study shows that even cognitively healthy individuals can quickly benefit from the regular inclusion of cocoa flavanols in their diets.

It is not yet fully understood how cocoa flavanols bring about improvements in cognitive function, but the study’s authors suggest that the improvements in insulin resistance and blood pressure could be revealing. 'Earlier studies suggest a central role for insulin resistance in brain ageing,' said Desideri. 'These results could therefore provide some insight into a possible mechanism of action for the cognitive improvements we have observed.' In addition to evaluating cognitive function, the researchers also monitored insulin resistance, blood pressure and other metabolic markers.

Excitingly, there was also evidence of improvements in these cardiometabolic outcomes. In the high- and intermediate-flavanol groups, both systolic and diastolic blood pressures were reduced and insulin resistance was significantly improved. In contrast, only a modest improvement in diastolic blood pressure was observed in the low-flavanol group, with no significant improvements in either systolic blood pressure or insulin resistance among the consumers of the low-flavanol drink.

During the past decade, there has been significant evidence indicating that consuming cocoa flavanols improves vascular function. Dr Catherine Kwik-Uribe, human health and nutrition director at Mars, Incorporated, and co-author on this latest study, said: 'As the brain is a heavily vascularised tissue, we might also be looking at vascular improvements as underlying the observed improvements in cognitive function.'

Dr Kwik-Uribe went on to speak about Mars’ flavanol research programme that has spanned more than two decades: 'The amount of research showing the beneficial effects of cocoa flavanol consumption is growing and Mars is proud to be a partner in important research like this that highlights the positive role cocoa flavanols may play in supporting healthy ageing.'