Dark chocolate is rich in a group of compounds called flavanols. Originally discovered because of their potent antioxidant activity, these flavanols have been found to have many health benefits. While the cocoa in dark chocolate is rich in flavanols, fruits, vegetables, red wine and tea all contain significant amounts of these too.

The interest in flavanols stems from more than their antioxidant effect. Flavanols can improve blood flow, regulate blood pressure, improve insulin sensitivity and immune responsiveness. Flavanols have even been linked to memory and cognition.

The mechanism for how flavanols have so many diverse effects on the vascular system is likely through increased bioavailability and bioactivity of nitric oxide.

Nitric oxide is an important cellular signalling molecule involved in many physiological processes.

Exercise is a potent stimulator of nitric oxide, but age and the presence of chronic health conditions can prevent many people from engaging in sufficient exercise to derive a health benefit. Researchers are now looking more closely at natural supplements, such as dark chocolate, that could potentially mimic some of the physiologic effects of exercise.

Researchers looked at the exercise capacity and molecular skeletal muscle changes in a group of 20 healthy, sedentary volunteers. The study involved consuming either 20 grams of dark chocolate or a placebo chocolate that was very low in cocoa flavanols each day for three months.

Even though there was no active exercise program involved as part of the study, those taking the dark chocolate saw a rise in VO2 max (a measure of maximum oxygen intake into the lungs) of 17 percent (just marginally below statistical significance) and an increase in their peak muscle power output. No such changes were seen in the placebo group.

The dark chocolate consumers also saw favourable changes in their HDL-cholesterol and triglyceride levels. At the molecular level of the muscle, there were also favourable changes in a range of controller proteins that are known to change with exercise and modulate changes in VO2 max and mitochondrial efficiency.

Implications

This research adds to the growing evidence base for the use of naturally occurring compounds found in many fruits and vegetables to help combat the ill effects of chronic disease and physical inactivity.

In the future, a daily ‘dose’ of dark chocolate a day may be what helps keep the doctor away.

Last Reviewed: 07/11/2019

© Norman Swan Medical Communications.



References

Taub PR at al. Beneficial effects of dark chocolate on exercise capacity in sedentary subjects: underlying mechanisms. A double blind, randomized, placebo controlled trial. Food & Function Epub online July 31, 2016. doi: 10.1039/c6fo00611f.