Consuming dark chocolate improves athletic performance. It was found that when consuming 40 g of dark chocolate daily, amateur cyclists were found to use less oxygen when when riding at a moderate pace for 20 minutes. These cyclists also traveled a longer distance in a two minute timed trial, during which they went rode as hard as they could.(1)
This was a small trial with nine cyclists, but it had a crossover design and one group ate white chocolate and did not get the same results. It is believed that these results from eating dark chocolate were because dark chocolate contains flavonols, including epichatecin, which has been shown to raise nitric oxide levels. Some athletes now consume beet juice because it has nitrates that raise nitric oxide levels in the body and this has been demonstrated in studies to dilate blood vessels and to improve glucose uptake and regulate muscular contraction.(2,3) But beet juice is not exactly great tasting. Dark chocolate seems to have some of the same properties as beet juice and is much more palatable.
Dark chocolate has been studied previously for its effects in reducing blood pressure in hypertensive subjects and for reducing the risk of coronary heart disease and stroke.(4,5) Dark chocolate, unique to other dietary nitrate supplements is hypothesised to mediate nitric oxide production through endothelium-dependent effects; related to flavanols’ ability to supress vascular arginase enzyme activity, thus increasing the production of nitric oxide.
References:
1. Patel RK, Brouner J, Spendiff O. Dark chocolate supplementation reduces the oxygen cost of moderate intensity cycling. Journal of the International Society of Sports Nutrition, 2015; 12 (1) DOI: 10.1186/s12970-015-0106-7.
2. Bailey SJ, Wilkerson DP, DiMenna FJ, Jones AM. Influence of repeated sprint training on pulmonary O2 uptake and muscle deoxygenation kinetics in humans. J Appl Physiol. 2009;106:1875-87.
3. Lansley KE, Winyard PG, Fulford J, Vanhatalo A, Bailey SJ, Blackwell JR, et al. Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study. J Appl Physiol. 2011;110:591-600.
4. Taubert D, Roesen R, Lehmann C, Jung N, Schomig E. Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial. JAMA. 2007;298:49-60.
5. Corti R, Flammer AJ, Hollenberg NK, Luscher TF. Cocoa and cardiovascular health. Circulation. 2009;119(10):1433-41.
