Clinical Studies on the Benefits of Chocolate

Boosting brain power -- with chocolate
Professor Ian Macdonald
School of Biomedical Sciences, University of Nottingham.

ABSTRACT: Eating chocolate could help to sharpen up the mind and give a short-term boost to cognitive skills, a University of Nottingham expert has found.

A study led by Professor Ian Macdonald found that consumption of a cocoa drink rich in flavanols -- a key ingredient of dark chocolate -- boosts blood flow to key areas of the brain for two to three hours.

Increased blood flow to these areas of the brain may help to increase performance in specific tasks and boost general alertness over a short period.

The findings, unveiled at one of the biggest scientific conferences in America, also raise the prospect of ingredients in chocolate being used to treat vascular impairment, including dementia and strokes, and thus for maintaining cardiovascular health.

The study also suggests that the cocoa flavanols found in chocolate could be useful in enhancing brain function for people fighting fatigue, sleep deprivation, and even the effects of ageing.

Ian Macdonald, professor of metabolic physiology at The University of Nottingham, used magnetic resonance imaging (MRI) to detect increased activity in specific areas of the brain in individuals who had consumed a single drink of flavanol-rich cocoa. The effect is linked to dilation of cerebral blood vessels, allowing more blood -- and therefore more oxygen -- to reach key areas of the brain.

Flavanols are not only found in chocolate with a high cocoa content -- they are also present in other substances such as red wine, green tea and blueberries.

He presented his research at the annual meeting of the American Association for the Advancement of Science (AAAS), one of the biggest annual gatherings of scientists from all over the world.

Professor Macdonald said: "Acute consumption of this particular flavanol-rich cocoa beverage was associated with increased grey matter flow for two to three hours."

"The demonstration of an effect of consuming this particular beverage on cerebral blood flow raises the possibility that certain food ingredients may be beneficial in increasing brain blood flow and enhancing brain function, in situations where individuals are cognitively impaired such as fatigue, sleep deprivation, or possibly ageing."

He emphasised that the level of cocoa flavanol used in the study is not available commercially. The cocoa-rich flavanol beverage was specially formulated for the purpose of the study.

Co-authors on the research were Dr Susan Francis, research associate Kay Head, and Professor Peter Morris, all from The University of Nottingham’s School of Physics and Astronomy.

Professor Macdonald is a member of the Food Standards Agency’s Scientific Advisory Committee on Nutrition, and is President-Elect of the UK Nutrition Society. His main research interests are concerned with the functional consequences of metabolic and nutritional disturbances in health and disease, with specific interests in obesity, diabetes, cardiovascular disease and exercise.

The AAAS, founded in 1848, is the world’s largest general scientific society and publisher of the prestigious international journal Science. Its annual conference draws up to 10,000 attendees.





The emerging role of flavonoid-rich cocoa and chocolate in cardiovascular health and disease
Engler MB, Engler MM.
Department of Physiological Nursing, Laboratory of Cardiovascular Physiology, University of California, San Francisco, California.

ABSTRACT: Cocoa and chocolate have recently been found to be rich plant-derived sources of antioxidant flavonoids with beneficial cardiovascular properties. These favorable physiological effects include: antioxidant activity, vasodilation and blood pressure reduction, inhibition of platelet activity, and decreased inflammation. Increasing evidence from experimental and clinical studies using cocoa-derived products and chocolate suggest an important role for these high-flavanol-containing foods in heart and vascular protection.

Nutrition Reviews;64(3):109-118.





Effect of dark chocolate on arterial function in healthy individuals
Vlachopoulos C, Alexopoulos N, Stefanadis C.
Hypertension Unit and Peripheral Vessels Unit, 1st Cardiology Department, Athens Medical School, Athens, Greece.

ABSTRACT: Cocoa has been consumed for at least 2500 years, and for a long time it has been regarded as a medicine. Arterial function is of paramount importance for the proper function and integrity of the cardiovascular system. Dark chocolate and flavonoid-rich cocoa have beneficial acute and short-term effects on endothelial function and wave reflections in normal individuals, in adults with cardiovascular risk factors, and in patients with coronary artery disease. Furthermore, dark chocolate and flavonoid-rich cocoa may have a blood pressure-lowering effect. These effects can be attributed to flavonoids and are mainly mediated through increased nitric oxide bioavailability. Further research is needed to demonstrate whether these effects of chocolate on arterial function are translated into clinical benefit.

Current Hypertension Reports;8(3):205-11.



Cocoa and chocolate flavonoids: implications for cardiovascular health
Steinberg FM, Bearden MM, Keen CL
Didactic Program in Dietetics, Department of Nutrition, University of California, Davis, California.

ABSTRACT: This paper offers a review of current scientific research regarding the potential cardiovascular health benefits of flavonoids found in cocoa and chocolate. Recent reports indicate that the main flavonoids found in cocoa, flavan-3-ols and their oligomeric derivatives, procyanidins, have a variety of beneficial actions, including antioxidant protection and modulation of vascular homeostasis [balance between blood clot formation and prevention]. These findings are supported by similar research on other flavonoid-rich foods. Other constituents in cocoa and chocolate that may also influence cardiovascular health are briefly reviewed. The lipid content of chocolate is relatively high; however, one third of the lipid in cocoa butter is composed of the fat stearic acid, which exerts a neutral cholesterolemic response in humans. Cocoa and chocolate contribute to trace mineral intake, which is necessary for optimum functioning of all biologic systems and for vascular tone. Thus, multiple components in chocolate, particularly flavonoids, can contribute to the complex interplay of nutrition and health. Applications of this knowledge include recommendations by health professionals to encourage individuals to consume a wide range of phytochemical-rich foods, which can include dark chocolate in moderate amounts.

Journal of the American Dietetic Association;103(2):215-23.