Thanks for the Memories, Cocoa
Memories are an integral part of who we are. You might even say they’re an important part of what makes us human. Memories inform everything we do. Without them we could not learn, grow, develop, change or even explore the implications of past actions.
It’s thought that all animals possess the ability to remember. Some, like elephants, are reputed to have remarkably detailed, long-term memories that allow them to recall a long-lost friend, or the gravesite of a departed loved one, across decades. Others, like goldfish, are thought to have memories, and attention spans, that are limited to a few months, at best. Even honey bees are able to remember complex information and convey it later to the hive.
Of course, as humans we form memories in early childhood and beyond that can last an entire lifetime. Or not, depending on how we age.
Some older individuals gradually lose the ability to remember events with the clarity they once managed. Of course, we’re all aware of the cruel disease, Alzheimer’s, which gradually robs the afflicted of their memories and abilities to think, learn and remember. But many older folks without the disease also succumb to failing memory. This form of memory loss, which is not associated with any particular disease process, is a common hallmark of advanced age. Known as age-related memory decline, this erosion of memories is thought to take place within a brain structure called the dentate gyrus.
Until recently, however, no one had documented that the dentate gyrus is involved in this process in humans. Using sophisticated brain imaging studies and simple tests of memorization, investigators were able to explore the workings of this structure among older test subjects. Some subjects received a special drink containing high amounts of compounds from cocoa—the source of chocolate—called flavanols. Flavanols are potent antioxidant compounds found in foods such as green tea leaves, cocoa, and certain fruits and vegetables.
For the study, subjects consumed an enriched high-flavanol drink, or an extremely low-flavanol substitute, for three months. Brain imaging and tests of memory were performed before and after the dietary intervention. "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. Memory also improved noticeably. "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 Scott A. Small, MD.
Previous studies have indicated that this high-flavanol formula is also protective against cardiovascular disease. It is not, however, presently available for purchase. Nor would it be simple to consume an equivalent amount of flavanols by eating high-quality chocolate.
For now, we’ll have to settle for an ounce or two of extremely-high-cocoa-content dark chocolate. And give thanks for the memories.
Adam M Brickman, Usman A Khan, Frank A Provenzano, Lok-Kin Yeung, Wendy Suzuki, Hagen Schroeter, Melanie Wall, Richard P Sloan, Scott A Small. Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults. Nature Neuroscience, 2014; DOI: 10.1038/nn.3850