Cocoa benefits for brain and heart

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The ancient Mayans considered cocoa―or cacao―the seed of the tree Theobroma cacao from which chocolate is derived, to be a gift of the gods. Rich in polyphenolic compounds, including flavanols, the use of cocoa for culinary and ritualistic purposes can be traced back thousands of years. It was also used medicinally, and these uses spread to European cultures by the mid-1500s.¹

In recent times, the use of chocolate as a sweet or confection has far outpaced its therapeutic use. However, as recent research is rediscovering, cocoa contains compounds that have significant anti-inflammatory and antioxidant potential. Scientists are now beginning to tout chocolate―specifically dark chocolate rich in polyphenols―as a health food. Several studies in recent years highlighted here show that chocolate’s potential benefits extend to cardiovascular function and brain wellness.

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Healthy Endothelium, Flexible Arteries

Telmo Pereira and colleagues from the Polytechnic Institute of Coimbra (Coimbra, Portugal) recently conducted a randomized study to assess the effects of long-term dark chocolate intake on several measures of heart and vascular function.²

Thirty healthy young adults between 18 and 27 years of age were asked to take 20 g of cocoa-enriched chocolate (with differing amounts of epicatechin, a powerful cocoa-derived flavanol) daily for 30 days. One group consumed low-cocoa chocolate (containing an average of 12.61 mg of epicatechin/g) while the other consumed a high-cocoa chocolate (average of 18.19 mg of epicatechin/g). Heart ultrasound imaging, carotid-femoral pulse wave velocity, carotid pulse wave analysis, flow mediated slowing (all measures of endothelial health), and an analysis of the ventricular-arterial coupling (a measure of the interaction between the left ventricle of the heart and the arterial system, which indicates cardiovascular efficiency) were measured at baseline and at study completion.

The results showed that high-cocoa chocolate led to statistically significant improvements in brachial and central systolic pulse pressure and measurements of ventricular-arterial coupling, indicating vascular benefits and increased cardiovascular efficiency. In addition, the high-cocoa chocolate group showed a trend towards improvement in measures of endothelial health, specifically in flow-mediated slowing and the augmentation index, which is a measure of arterial stiffness. These findings indicate systemic heart health benefits in those taking chocolate with a higher epicatechin content.

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 Elevated Executive Function

Aerobic exercise is known to acutely enhance executive function and memory. Hayato Tsukamoto and colleagues from Ritsumeikan University (Shiga, Japan) aimed to evaluate the additive effects of cocoa flavanol consumption on further enhancing the cognitive benefits of exercise in healthy adults.³

In the study, 10 young men received either a high-cocoa flavanol-containing beverage (563 mg of cocoa flavanol) or a low-flavanol beverage (38 mg cocoa flavanols) 70 minutes prior to performing a moderate-intensity cycling task. Each participant then performed a color-word Stroop task and face-name matching task to assess executive function and memory at six time points throughout the session.

The high-flavanol beverage enhanced executive function prior to the exercise task, and this effect carried through on post-exercise measures. While executive function also improved in the low-flavanol beverage group, it failed to reach the levels associated with high-flavanol consumption. Memory function, however, did not improve.

The results of the study suggest that consuming a beverage high in cocoa flavanols prior to exercise has an additional benefit on the executive function improvements associated with physical activity.

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Cerebral Blood Flow Booster

Channa Marsh and colleagues from the University of Western Australia (Crawley, Western Australia, Australia) recently sought to investigate the acute vascular and cognitive effects of cocoa consumption in postmenopausal women.⁴

In the study, 12 healthy postmenopausal women with an average age of 57 were included in a round of three experiments, each separated by one week. After a familiarization session during which the study protocol and assessments were explained, participants consumed an 85-g serving of white chocolate (0% cocoa, 35 mg polyphenols), milk chocolate (35% cocoa, 200 mg polyphenols), or dark chocolate (80% cocoa, 395 mg polyphenols) on one of three occasions.

At the end of the study, significant decreases in cerebral blood flow velocity were seen after consumption of milk chocolate and dark chocolate whereas no changes were observed with white chocolate. This finding suggests an increase in cerebrovascular efficiency. Furthermore, a significant increase in flow-mediated dilation, a measure of endothelial function that is mediated by nitric oxide, was notable after dark chocolate consumption, but not following milk or white chocolate consumption.

While no changes were seen on the cognitive function tests employed, these findings suggest important benefits of acute dark chocolate consumption on endothelial function and brain blood flow parameters.

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Enhanced Blood Cell Flexibility

While cocoa flavanols are known to affect blood flow properties, their mechanism of action remains unclear. To assess this, Jana Radosinska and colleagues from Comenius University in Bratislava (Bratislava, Slovak Republic) aimed to determine the impact of acute dark chocolate (85% cocoa) or milk chocolate (30% cocoa) intake on erythrocyte deformability, which is the ability of red blood cells to change shape as they move through blood vessels without rupturing. Higher erythrocyte deformability is advantageous for blood flow and circulation.

In the study⁵, 68 healthy adults with an average age of 21 were assigned to the milk chocolate or dark chocolate group and asked to consume a standardized breakfast including their specified chocolate in an amount of 1 g/kg of body weight. Blood was drawn at baseline and two hours after ingestion of the meal.

Erythrocyte deformability significantly increased in the group consuming dark chocolate, but not in those consuming milk chocolate. Total antioxidant capacity of plasma showed no change in either group. Researchers also noted that production of nitric oxide, a compound important for endothelial health, decreased significantly from baseline levels in the milk chocolate group while it remained steady in those consuming dark chocolate.

These results suggest that dark chocolate intake improves erythrocyte deformability and maintains nitric oxide levels, potentially leading to improved blood flow and better tissue oxygenation.

References:

1. Mellor D et al. “Cocoa and chocolate their clinical benefits: Insights in study design.” CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, vol. 12, no. 18 (2017): 1-7
2. Pereira T et al. “Randomized study of the effects of cocoa-rich chocolate on the vascular function and the ventricular-arterial coupling of young and healthy adults.” Journal of Hypertension. Published online June 1, 2018.
3. Tsukamoto H et al. “Flavanol-rich cocoa consumption enhances exercise-induced executive function improvements in humans.” Nutrition. Published online September 28, 2017.
4. Marsh CE et al. “Brachial and cerebrovascular functions are enhanced in postmenopausal women after ingestion of chocolate with a high concentration of cocoa.” The Journal of Nutrition, vol. 147, no. 9 (September 2017):1686-1692
5. Radosinska J et al. “Acute dark chocolate ingestion is beneficial for hemodynamics via enhancement of erythrocyte deformability in healthy humans.” Nutrition Research. Published online March 7, 2017.