The Role of Diet on Cognitive Health
New study is the second installment in a two-part investigation of the effects cocoa flavanols may have on the brain
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 just published in the AJCN looked to address this question. Enrolling men and women aged 61-85 years with no evidence of cognitive dysfunction, the participants in this controlled, randomized, double-blind study were assigned to one of three flavanol groups, consuming a drink containing either high (993 mg), intermediate (520 mg) or low (48 mg) amounts of cocoa flavanols every day for eight 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, alkalized 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 again after eight weeks, cognitive function was assessed using a battery of tests that examined memory, retention, 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 eight 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.
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.
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 aging," said Desideri. "These results could therefore provide some insight into a possible mechanism of action for the cognitive improvements we have observed."
Over 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, "Since the brain is a heavily vascularized 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 program that has spanned over 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 aging."
Dr. Desideri and his team are already thinking about the next steps: "It is clear from our latest research and other recent studies that cocoa flavanols have profound effects on the body, and specifically the brain," said Desideri. "Now we'd like to know how they work and how long the effects last. If these further studies confirm the findings that brain health can be improved by consuming dietary flavanols, it may have the potential to affect the daily lives of millions of people world-wide."