Can a chocolate bar a day really stave off age-related memory loss?
Not exactly, but new research suggests that a high dosage of flavanols, a group of substances found in cocoa and tea may reverse age-related memory decline.
“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 Dr. Scott Small, a neurology professor at Columbia University in New York, in a statement. He is the senior author of a paper describing the effects of flavanols on cognitive skills.
Cognitive abilities naturally decline with age and can have, by the 50s or 60s, an impact on remembering names of new people or where a person might have left their keys
For the study, researchers gave volunteers aged between 50 and 69 a high-flavanol drink derived from cocoa beans or a low-flavanol drink. The drink was made by Mars, Inc., a global chocolate manufacturer, which partly supported the research.
Some subjects got a high dose of flavanol, 900 milligrams a day for three months, while others got a low-grade flavanol drink containing only 10 milligrams.
Brain imaging and memory tests were administered to each participant before and after the study and focused on the blood volume in a part of the brain called the dentate gyrus. The dentate gyrus is a part of the hippocampus responsible for creating new memories.
The subjects also took a 20-minute memory test involving pattern recognition “to evaluate a type of memory controlled by the dentate gyrus.”
Flavanols extracted from cocoa beans had previously been found to improve neuronal connections in the dentate gyrus of mice.
On humans, the researchers say they “found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink.” Those who had the high doses also performed better on the memory test, researchers said.
Craig Stark, a neurobiologist at the University of California, Irvine, who was not involved in the research, told the New York Times that the results of the study were "exciting."
But before you go out and buy a bunch of chocolate, Small says many chocolate makers filter out the flavanols, but even if you got a bar that still had them, you’d have to eat 25 per day to get the levels given to the test subjects, he said.
“That’s not something I’d recommend as a physician,” he said. “It would counter any of the benefits.”
Still, we may not be far from cocoa-based flavanol extracts, but Small says future, larger studies will determine what’s the minimal amount of flavanols that could be administered to achieve results.
Interestingly, the participants who also exercised four times a week during the study showed that exercise had no effects on memory improvement.
Since we didn’t reach the intended VO2max (maximal oxygen uptake) target,” said Small, “we couldn’t evaluate whether exercise was beneficial in this context. This is not to say that exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects.”
Flavanols have also been shown to improve cardiovascular health, and Brigham and Women’s Hospital in Boston recently announced an NIH-funded study of 18,000 men and women to see if they could prevent heart attacks and strokes.
The study was published in the online issue of Nature Neuroscience.
Here's a short interview with Dr. Small: