Add life (and cognition) to your pleasure . . .

Chocolate Can Make You Smarter
Make sure you get your daily quota

By Will Block

Stay away from my xocolātl.

Y ou can’t take it with you! Or so you’ve heard. Yet chemical analyses of residues collected from ancient vessels found in an Early Classic Mayan tomb beg to differ. The composition of the remains? Theobromine and caffeine, indicating that chocolate was so well loved that it was taken to the grave, at least in the culture that gave birth to it.1 But given what we are learning about chocolate, it may be much more important to have it in this world.

Chocolate consists of numerous raw and processed foods that utilize the seed of the tropical Theobroma cacao tree. Cultivated for at least three thousand years in Mexico, and Central and South America—with its earliest documented use around 1100 BC—most Mesoamerican peoples produced chocolate beverages, including the fearsome Aztecs, whose beverage was known as xocolātl, a word meaning “bitter water.” Indeed the seeds of the cacao tree have an intense bitter taste, so they must be fermented to develop the flavor. And what flavor!

Why Chocolate is Revered . . .

On into the 21st Century, the development of allegedly penultimate chocolate beverages and foods continues, and for good, but generally unidentified, reasons. But now, a new study provides a piece of the puzzle to why cocoa may have been so revered. Cocoa flavonols, a primary ingredient of chocolate, have been found to positively influence physiological processes in ways suggesting that their consumption may improve cognitive function. In a new study,2 researchers from several English universities, under the leadership of Professor Andrew Scholey of Swinburne University’s Centre for the Study of Natural Medicines and Neurocognition, Brain Sciences Institute, Melbourne, Australia, investigated the cognitive and subjective effects of cocoa flavanols consumption during times of sustained mental demand, and what they found was especially exciting, because chocolate tastes so good and is its own motivator for compliance.

Faster Processing and Less Fatigue

Employing the format of a randomized, controlled, double-blinded, balanced, three period crossover trial, scientists measured the results of 30 healthy adults who drank cocoa flavanol beverages. Containing either 520 mg or 994 mg of these flavonols, beverage consumption was compared to matched controls, with a three-day washout between drinks. Measurements included anxiety factors and repetitive short cycles of a series of tests designed to measure cognition. Positive results were found for both doses, including speeded Rapid Visual Information Processing responses for the higher dose and improved “mental fatigue” for the lower dose. This is the first time that acute cognitive improvements have been reported for the consumption of cocoa flavonols in healthy adults. While the mechanisms underlying the effects are not clear, it is thought that improved endothelial function and blood flow may be responsible.

Flavanols are found within the class of flavonoids, natural compounds that are ever-present in plants. In our diets, flavanols can be found especially in common foods such as red wine, apples, grapes, teas, and cocoa and cocoa-containing products. In this last category, cocoa, they are particularly plentiful, and are found as simple monomeric flavanols—principally (–)-epicatechin and to a much lesser extent, (+)-catechin—as well as the dimeric and oligomeric flavanols known as procyanidins.

Improved Cardiovascular Function, Insulin Sensitivity, and Blood Pressure

Cacao pod
As reported by Scholey et al., research into flavanols has recently increased, as has interest in the potential health benefits associated with the consumption of flavanol-containing foods. Among the benefits attributed to flavanols are improvements in cardiovascular as well as cognitive functions. Specifically, dietary intervention trials have found that eating more flavanol-containing cocoa products can reduce platelet aggregation, enhance insulin sensitivity, and blood pressure. Moreover, other evidence is compiling that can improve peripheral and central blood flow. Although researchers are not clear on the mechanisms, it is thought that the effects are probably related to increased nitric oxide synthesis within blood vessels.

Cocoa Flavanols Can Produce Acute Neurocognitive Effects

Other evidence finds that unhealthy variations in blood flow are improved following ingestion of cocoa. Honing in on the underlying science that led to the cognitive hypothesis, there are findings that eating cocoa flavanols is connected to increased cerebral blood flow and brain activation. In an earlier study,3 a scientific team administered 150 mg/day of cocoa flavanols in drink form for 5 days to 16 healthy young subjects and then examined the effects on brain activation during a cognitive task. Employing cognitive testing and functional magnetic resonance imaging, when compared to controls, the cocoa flavanol drink was associated with greater activation of three task-relevant brain areas. In the final analysis, the results suggest that cocoa flavanols can produce acute neurocognitive effects. Noteworthy, the study used an executive/attentional switching task with relatively heavy task demands.


This is the first time that acute
cognitive improvements have been
reported for the consumption of
cocoa flavonols in healthy adults.


Eliminating Ceiling Effects

More recently, researchers from Virginia Polytechnic Institute and State University evaluated the cognitive effects of cocoa. In this study, 101 cognitively intact elderly subjects (>60 years old) were administered 37 g dark chocolate (containing 397 mg of cocoa procyanidins) along with a 273-ml cocoa drink (total 357 mg of cocoa procyanidins) or matching placebo products every day for six weeks. Although there were no treatment-related changes in cognitive function, the authors thought that the results may have been confounded. The possibility that participants were approaching ceiling performance, abrogating any cocoa effects on cognition, could not be ruled out. From their thinking, Sholey et al. concluded that a study would need to eliminate ceiling effects, to find the true effects, and that this could be done by subjecting the participants to sustained effortful processing that leads to a progressive performance decline, even in healthy young adults. They believe this has been borne out by other studies.

On Combining Cocoa with Other Beneficial Ingredients

The problem with chocolate is that cocoa is often combined with other ingredients such as sugar, fat, and carbohydrates that are not good for your health. Yet there are a few formulations of chocolate products that preserve all the natural goodness, while avoiding all the bad things. So if you want to make the most of the chocolate experience, you might avoid the “death by chocolate” desserts, which might just as well be called deserts (one “s”) because they make a wasteland out of you.

Given cocoa’s effects on vascular function and blood flow, Sholey and colleagues hypothesized that cocoa flavanols should show positively on mentally demanding tasks while lowering mental fatigue associated with performing such tasks. Using this insight, the researchers demonstrated that their approach was correct and that the benefits for cocoa flavanols consumption was buried by ceiling effects. Both cocoa flavanols-rich drinks in their study influenced the same performance measures, but the higher (994 mg) drink did not do as well with reducing mental fatigue. This was perhaps owing to the possibity that anxiety may have been influenced by the caffeine contained within the drinks. The effects of lower levels of cocoa flavanols may merit further exploration because the lowest psychoactive dose should always be established. Another consideration that may play a role is the potential adaptogenic (or resistance-building) properties of cocoa flavanols. This could be further explored by monitoring performance during psychological stress following cocoa flavanols ingestion.

Neuroprotection Too

Certainly, there is epidemiological evidence to suggest that long-term flavanol intake has neurocognitive benefits including neuroprotection. On the other hand, seemingly compelling epidemiological data are often not translated into positive findings in clinical trials. Nonetheless, future studies might examine the habitual consumption of caffeine, and other drink components, which may have been responsible for fluctuations in acute levels that could influence aspects of cognitive performance. The exact mechanisms of cocoa that influence cognition are not fully understood.


Dietary intervention trials have found
that eating more flavanol-containing
cocoa products can reduce platelet
aggregation, enhance insulin
sensitivity, and blood pressure.


Other research has focused on the anti-oxidant properties of cocoa flavanols, yet this value has recently been challenged. This is so because of the extensive biotransformation that occurs following ingestion, reducing the anti-oxidant capacity. Furthermore, what typically gets absorbed from cocoa flavanols are not the components with anti-oxidant properties. Also, the rudimentary level of antioxidants in cocoa flavanols may have been overstated. Prior studies indicate that acute consumption (200–500 mg) of cocoa flavanols is able to increase blood vessel dilation and this benefit may be owing to metabolic substrates, also possible factors for enhanced performance of cognitively demanding tasks. Altogether, the results of Scholey et al. bolster earlier findings showing that those natural nutrients which increase cerebral blood flow and/or metabolic activity also shine brightly in improving cognitive processing during prolonged mental effort.

Chocolate Is Loved

At the end of the day, Scholey and colleagues remain solid on their findings. The consumption of cocoa flavanols may produce enhanced performance and elevated mood during cognitive processing that is highly effortful. And the public remains solid on chocolate’s effects, albeit for the gratification of extraordinary taste, pleasure, and the happiness factor (attributed to cocoa’s beta-phenylethylamine, the “love molecule”).* There can be little objection that further exploration is merited, into cocoa flavanols’ effects in other populations, over longer time periods, and at different doses. Why wait?


*See “Phenylalanine May Cheer You Up” in the August 2008 issue.


References

  1. Hall GD, Tarka SM, Hurst WJ,. Stuart D, Adams REW. Cacao residues in ancient Maya vessels. from Rio Azul, Guatemala. Ameri Antiq 1990 55(1):138–43.
  2. Scholey AB, French SJ, Morris PJ, Kennedy DO, Milne AL, Haskell CF. Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort. J Psychopharmacol 2009 Nov 26. [Epub ahead of print]
  3. Francis S, Head K, Morris PG, Macdonald IA. The effect of flavanol-rich cocoa on the fMRI response to a cognitive task in healthy young people. J Cardiovasc Pharmacol 2006;47:S215–20.


Will Block is the publisher and editorial director of Life Enhancement magazine.

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