I bet as mid-February rolls around you have one thing on your mind – chocolate. Or, maybe love? Nope. Chocolate! Ah, what is it about that perfect piece of chocolate that makes you want to purr with delight? And, since this is a neuroscience blog, what is the scoop on chocolate and the brain? Why do some people crave chocolate so much that nothing else will do?
Scientists have studied cocoa and chocolate for years in search of answers. I imagine that involved eating a lot of chocolate! They have identified over 300 chemicals in cocoa products, some of which have the potential to be neuro-active. However, these compounds are present in tiny amounts and once eaten, it is difficult to know how much of each reaches the brain. Compounds studied include tryptophan and serotonin - associated with feelings of relaxation; caffeine and theobromine which act as neural stimulants to increase alertness; phenylethylamine which promotes brain release of dopamine which is associated with pleasure. As always, there is that contingent of scientists that find cannabinoids hold the key to everything. They theorize that either cannabinoid-mimics or agents boosting release of brain-produced cannabinoids produce the pleasurable effects of chocolate. In related studies, eating chocolate prompts brain production of natural opiates which dull pain and increase feelings of well-being.
Sounds good, but the truth is that many fruits and vegetables contain compounds similar to those in chocolate. You won’t find people giving out broccoli or onion hearts as a treat to their special someone, though! So, it may be unique chemical combinations that give chocolate its special edge even over sweet treats like caramels, suggesting it is not just sugar, fats and dairy in some chocolates that make them crave-worthy.
Setting aside the feel-good aspect, does cocoa or chocolate actually benefit human brain function? Several studies have focused on potent antioxidant and anti-inflammatory agents (flavanols) in cocoa products. These have known benefits for cardiovascular health. However, their effects on cognition and behavior are unproven. When you eat chocolate, flavanols accumulate in brain regions involved in learning and memory, especially the hippocampus. Their neurobiological actions are thought to occur via increased expression of proteins which enhance neurogenesis, neuronal function and connectivity, and via improved brain blood flow. Protective effects of long-term flavanol intake on cognition, behavior, and age- or disease-related cognitive decline are seen in animal models of aging, dementia, and stroke.
Unfortunately, few human studies can corroborate these findings. A 2017 review of multiple studies on the subject found some showing better memory performance in people taking high flavanol cocoa supplements for 3 months. Other studies demonstrated improved blood flow, oxygenation, and neuronal function in the brain after consumption of cocoa drinks, but the changes were often not associated with improved performance on cognitive tasks. The authors concluded that studies so far have been small, sometimes show contradictory results, and do not control adequately for other variables that may affect outcomes.
So, it will take more than the evidence we have now to establish that chocolate can truly preserve or improve brain function. How disappointing for those of us who are anxious to accept any suggestion that eating more chocolate is healthy for the brain! Oh well then, it is back to exercise, healthy diet, good sleep and not stressing out. Hmm, where did i put that chocolate bar?
Post by: Nadia Fike
Read more: 1. Brain Cannabinoids in Chocolate, Nature, August 22, 1996, pp. 677-678 by diTomaso, E et al. 2. Enhancing Human Cognition with Cocoa Flavonoids, Frontiers in Nutrition, 2017; 4: 19. by Socci, V et al.