I have a confession to make: I have been in a long, enduring love affair with chocolate. And I must say, it was love at first bite. Though I am usually able to justify my excessive chocolate consumption with the saying, “if it’s not good for the body, it’s good for the soul,” I am always looking out for any news about the benefits of consuming this wonderful treat.
So when I read earlier this week that a country’s chocolate consumption per capita is strongly correlated with the number of Nobel laureates (per 10 million population) from that country, I was pretty enthused. A win for chocolate!
Before I could get too excited about these findings, that little voice in my head started nagging me, “but correlation does not imply causality!” And that little voice was, as usual, right: knowing that these two things–chocolate consumption and number of Nobel laureates–are associated does not mean one causes the other. But could there be a real link here?
Short answer: It’s possible. Several studies (Nurk et al., Desideri et al., and Field et al., to name a few) have linked consumption of cocoa-containing products with increased performance on cognitive tasks.
But what is it about chocolate (other than its dreamy texture and magically rich taste) that gives it these beneficial effects? Scientists give credit to flavonoids, a class of compounds important to plant functioning. Flavanols are the primary type of flavonoid found in the cacao tree’s beans, which are used to make cocoa and chocolate products. Although the processing of the cacao plant to create chocolate removes much of this flavanol content, what does remain is still substantial, especially in the darker, more bitter chocolates. When consumed, these cocoa flavanols enhance blood flow in the body. One of the more scientifically-supported explanations for this is that cocoa flavanols stimulate the activity of nitric oxide, which helps blood vessels to “relax” (i.e. dilate) and also reduces adhesion and aggregation of blood platelets.
So might this increased blood flow contribute to enhanced cognitive performance? Though most studies have just looked at the relationship between consumption of cocoa flavanols and cognitive performance, one study of healthy young people took it a step further and actually measured brain activity and blood flow in response to chocolate consumption. Those who consumed flavanol-rich cocoas for five days straight prior to a cognitive task had higher-intensity brain activity during the task than those who didn’t consume cocoas prior to the task. Further, it appears as though blood flow (not simply direct neural stimulation) was, in part, responsible for this brain surge: scientists observed that a single dose of cocoa rich in flavanols increased blood flow to the brain, particularly to the gray matter within the brain, thought to play a role in muscle control, sensory perception, and even memory.
Because of this blood-flow-enhancing effect, cocoa flavanols not only improve circulation to important organs like the brain, but also have been shown to lower blood pressure and promote heart and cardiovascular health, more generally. A meta-analytic review looking at chocolate consumption and cardiometabolic disorders (such as heart attack and stroke, as well as diabetes) revealed that, of the seven studies reviewed, five found a correlation between higher chocolate consumption and reduced risk for cardiometabolic disorders. And the body of research continues to grow–earlier this year a study was published revealing a link between moderate chocolate consumption and reduced risk of stroke in males.
Some researchers go as far as to claim that high-flavanol chocolate is a cost-effective treatment strategy for those at high risk for heart disease or those with cognitive impairments. Others say chocolate still can’t hold a candle to modern medications. What most would agree on is that, like many things, chocolate probably has health benefits, as long as it’s consumed in moderation.
But with Halloween right around the corner, and all that good stuff for sale in the convenience stores, my fellow chocoholics and I might have to casually ignore that “in moderation” part…at least for a couple of weeks!
Sources (in order of reference):
Messerli FH. (2012). Chocolate consumption, cognitive function, and Nobel laureates. The New England Journal of Medicine, 367, 1562-1564.
Nurk E, Refsum H, Drevon CA, et al. (2011). Intake of flavonoid-rich wine, tea, and chocolate by elderly men and women is associated with better cognitive test performance1-3. Journal of Nutrition, 139(1):120–127.
Desideri G, Kwik-Uribe C, Grassi D, et al. (2012). Benefits in cognitive function, blood pressure, and insulin resistance through cocoa flavanol consumption in elderly subjects with mild cognitive impairment: the Cocoa, Cognition, and Aging (CoCoA) study. Hypertension, 60(3), 794-801.
Field DT, Williams CM, & Butler LT. (2011). Consumption of cocoa flavanols results in an acute improvement in visual and cognitive functions. Physiology and Behavior, 103(3-4), 255–260.
Corti AJ, Hollenberg NK, & Luscher, TF. (2009). Cocoa and cardiovascular health. Circulation, 119, 1433-1441.
Francis ST, Head K, Morris PG, et al. (2006). The effect of flavanol-rich cocoa on the fMRI response to a cognitive task in healthy young people. Journal of Cardiovascular Pharmacology, 47 (Suppl 2):S215-20–S215-S220.
Desch S, Schmidt J, Kobler D, et al. (2009). Effect of cocoa products on blood pressure: Systematic review and meta-analysis. American Journal of Hypertension, 23(1), 97-103.
Buitrago-Lopez A, Sanderson J, Johnson L, et al. (2011). Chocolate consumption and cardiometabolic disorders: Systematic review and meta-analysis. BMJ, 343,d4488.
Larsson SC, Vitarmo J, & Wolk A. (2012). Chocolate consumption and risk of stroke: a prospective cohort of men and meta-analysis. Neurology, 79(12), 1223-1229.