Endurance health: the power of cocoa!

Around the turn of the century, scientists began to take a keen interest in the potential health benefits of cocoa products such as dark chocolate (defined as containing 70% or more cocoa solids) and cocoa beverages. This was because they had identified that the humble cocoa bean is a very rich source of source of polyphenol and flavanol antioxidants, which are known in other foods to help reduce the incidence of various degenerative diseases, especially cardiovascular disease⁽¹⁾. In particular, it emerged consuming higher levels of flavanols in cocoa products seemed to result in lower (and healthier) blood pressure levels⁽²⁾. These findings were also supported by real world observations in communities known to consume large quantities of flavanol-rich cocoa, and where cardiovascular disease is almost absent⁽³⁾.

Cocoa, dark chocolate & longevity

As research has progressed, the benefits of cocoa products have now been observed more widely across different populations. In a 2022 study on cocoa consumption and health/mortality, researchers found a highly protective effect from cocoa⁽⁴⁾. Many of the cardiovascular benefits (and potential performance benefits) arising from cocoa product consumption are believed to occur via improved blood flow - particularly through the micro-capillaries of muscle tissue - thanks to the flavanols present^(5-8). Cocoa flavanols achieve this by stimulating an enzyme call ‘NO synthase’, which leads to high levels of nitric oxide (NO) synthesis. NO is a powerful blood vessel relaxant, enabling blood vessels to dilate (vasodilation), resulting in improved blood flow and reduced blood pressure.

In an SPB article last year, we looked at research on how already healthy sportsmen and women might experience further health gains from consuming dark chocolate. In summary, this research on soccer players showed that consuming 30 grams of dark chocolate per day produced the following benefits⁽⁹⁾:

·        A decrease in total blood cholesterol.

·        A drop in LDL cholesterol (the kind associated with increased risk of cardiovascular disease) of 18.5mg/dl and an increase in ‘cardio protective’ HDL cholesterol of 3.3mg/dl.

·        A drop in blood triglycerides of 6.3mg/dl (high blood triglycerides are associated with increased cardiovascular risk).

·        A very large and positive impact on a key determinant of omega-3 index – the arachidonic to eicosapentaenoic acid (AA:EPA) ratio.

·        A more stable gut flora balance throughout the 30-day intervention, with fewer fluctuations than were seen in the control group (indicating more robust gut health).

Endurance athletes and dark chocolate

Endurance capacity is directly related to the ability of the circulatory and vascular systems to support prolonged physical activity such as running⁽¹⁰⁾. In addition, recent research has established that cocoa/dark chocolate can reduce ‘arterial stiffness’⁽¹¹⁾. The arteries are the large vessels that deliver oxygenated blood all around the body.

Healthy young arteries have elastic properties, which helps accommodate and reduce the blood pressure peaks produced by each heartbeat. As arteries age and as a result of poor diet and lifestyle, arteries tend to stiffen as the years pass by. The stiffer and harder the blood vessel walls, the more the heart has to work to pump blood into the arteries; in those with stiffer arterial walls only a small fraction of each cardiac stroke volume can be utilized for blood circulation without increasing the blood pressure.

Given that we now know cocoa/dark chocolate can not only enhance vascular function, but also lower arterial stiffness – both of which are key factors during endurance exercise - can consumption of these products enhance endurance performance in athletes such as runners? To date, there’s been very research into this topic but new research by a team of Greek researchers has attempted to find some answers.