A new study has found that dietary cocoa flavanols — naturally occurring bioactives found in cocoa — reversed age-related memory decline in healthy older adults.
The study shows that a component of age-related memory decline 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, according to researchers at Columbia University Medical Center (CUMC).
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 they parked their car or left their keys.
This normal age-related memory decline starts in early adulthood, but usually does not have any noticeable impact on quality of life until people reach their 50s or 60s, according to the researchers.
They note that age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer’s, in which the disease 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, MD, had shown that changes in a specific part of the brain — the dentate gyrus — are associated with age-related memory decline. Until now, however, the evidence in humans showed only a correlational link, not a causal one, according to the researchers.
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 had previously been found to improve neuronal connections in the dentate gyrus of mice, the researcher noted.
For the study, a cocoa flavanol-containing test drink was produced by the food company Mars, Incorporated, which also partly supported the research, using a proprietary process to extract flavanols from cocoa beans, according to the research team.
Most methods of processing cocoa remove many of the flavanols found in the raw plant, the researchers noted.
The researchers then recruited 37 healthy volunteers, between the ages of 50 and 69, who were randomly assigned 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.
The memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus, the researches explained.
“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, PhD, associate professor of neuropsychology at the Taub Institute.
The high-flavanol group also performed significantly better on the memory test, the study found.
“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.
He cautioned, however, that the findings need to be replicated in a larger study, which he and his team plan to do.
The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to improve memory.
The study was published in Nature Neuroscience.