An unfortunate side effect of aging is often decreased memory function. Age-related memory decline is linked to the dentate gyrus region of the hippocampus, which is a different part of the brain than the one affecting people with early Alzheimer’s or other neurodegenerative disease. A team of researchers have found that increasing dietary cocoa flavanols can improve brain function in this region, and even lead to better scores in memory tests. Adam Brickman of Columbia University’s Taub Institute for Research on Alzheimer's Disease and the Aging Brain was the lead author on the paper, which was published in Nature Neuroscience.
The dentate gyrus has been implicated in previous memory-related studies, though the link seemed to be more correlative than causal. In order to establish a relationship between the two, the researchers wanted to boost activity in that region of the brain, and see if it would affect memory. Flavanols are chemicals found in raw, unprocessed cocoa beans as well as some other plant material. They were chosen for this study, as prior research uncovered that flavanol is able to act on the dentate gyrus, boosting the number of neuronal connections, and thus, function.
The hippocampus is shown in yellow. The dentate gyrus, which affects age-related memory loss is shown in green, while the entorhinal cortex, affected by Alzheimer's, is shown in purple. Image credit: Lab of Scott A. Small
This was a relatively small study, using 37 healthy participants ranging in age from 50 to 69. Over the course of three months, one group drank a specially-formulated, high-flavanol beverage with 900 mg of flavanols per day, while the other group consumed a low-flavanol 10 mg drink each day. Each participant underwent a pattern-recognition memory test and brain imaging before and after the three months of drinking flavanols.
"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,” Brickman said in a press release.
In addition to the boost in neuronal connections in the dentate gyrus, memory test scores also improved for those receiving a high level of dietary flavanols, finally showing a causal link between the two. After the three month study, those drinking high levels of flavanols had the working memory of someone decades younger than themselves.
“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,” added principal investigator Scott Small.
Though age-related memory decline and Alzheimer's both affect the hippocampus, they do not act on the same regions. Image credit: Columbia University Medical Center
The team’s next step is to replicate this experiment with a larger group of test subjects in order to better understand the relationship between flavanols, the hippocampus, and memory.
Apologies to anyone with a sweet tooth: this study does not give free reign to pig out on chocolate this Halloween weekend. Chocolate is not a great source of these flavonoids. While fine dark chocolate will comprise anywhere from 45 to 80% cocoa, the chocolate found in the average candy bar has only 5 to 7%. Additionally, chocolate also has added sugar and fat, which may negate any benefits that come from eating the cocoa.
[Header image by Everjean via flickr]