Cocoa can reverse age-related memory decline in healthy older adults by improving brain function, according to a new study.
Researchers led by Columbia University Medical Center (CUMC) found that dietary cocoa flavanols - naturally occurring bioactives found in cocoa - reversed age-related memory decline.
The study provides the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and that this form of memory decline can be improved by a dietary intervention.
As people age, they typically show some decline in cognitive abilities, including learning and remembering such things as the names of new acquaintances or where one parked the car or placed one's keys.
Age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer's, in which a disease process damages and destroys neurons in various parts of the brain, including the memory circuits.
Previous work, including by the laboratory of senior author Scott A Small, had shown that changes in a specific part of the brain - the dentate gyrus - are associated with age-related memory decline.
To see if the dentate gyrus is the source of age-related memory decline in humans, Small and his colleagues tested whether compounds called cocoa flavanols can improve the function of this brain region and improve memory.
Flavanols extracted from cocoa beans have been found to improve neuronal connections in the dentate gyrus of mice.
A cocoa flavanol-containing test drink prepared specifically for research purposes was produced by the food company Mars, Incorporated.
In the study, 37 healthy volunteers, ages 50 to 69, were randomised to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. Brain imaging and memory tests were administered to each participant before and after the study.
The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.
"When we imaged our research subjects' brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink," said lead author Adam M Brickman, associate professor of neuropsychology at the Taub Institute at CUMC.
The high-flavanol group also performed significantly better on the memory test.
"If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old," said Small.
The study is published in the journal Nature Neuroscience.