Daily consumption of 40 grams of dark chocolate was associated with significant improvements in gas exchange threshold (GET), a measure of cardiorespiratory fitness and endurance capacity, and time trial performance, compared to both baseline values and white chocolate.
The study is said to be the first study to investigate the effects of dark chocolate on these measures, wrote scientists from Kingston University in England in the Journal of the International Society of Sports Nutrition.
“The primary outcome observed was dark chocolate consumption increased the work rate achieved at GET by 11% compared to white chocolate and 21% compared to baseline. Time trial distances following dark chocolate consumption were higher compared to baseline and white chocolate,” they wrote.
“Consequently, it can be concluded that ingestion of dark chocolate for 14 days reduced the oxygen cost of moderate intensity exercise and may be an effective ergogenic aid for short-duration moderate intensity exercise.”
Cocoa’s benefits
The health benefits of polyphenols from cocoa have been gathering increasing column inches in the national media. To date studies have reported potential benefits for cardiovascular health, skin health, and even brain health.
The majority of science into the potential benefits of cocoa have revolved around cardiovascular benefits of the flavanols (also known as flavan-3-ols or catechins), and particularly the monomeric flavanol (-)epicatechin.
Swiss choc giant Barry Callebaut recently enjoyed success in Europe with its EFSA-approved cocoa flavanol health claim being written into EU law by the European Commission last year. The claim says that eating 200 mg of cocoa flavanols daily either from cocoa beverages or dark chocolate contributes to normal blood flow.
Study details
The new study indicates that dark chocolate may also have potential for sports nutrition applications. Led by Rishikesh Patel, the researchers recruited nine moderately-trained men to participate in their study. The men underwent a series of fitness tests at the start of the study and were then randomly assigned to receive 40 grams per day of dark or white chocolate for two weeks. At the end of this time they underwent the same tests as at the start. The men were also crossed over to the other intervention for a further two weeks.
Results showed that GET increased by 11% compared to white chocolate and 21% compared to baseline. In addition, results from the time trial indicated that the dark chocolate intervention was associated with a 17% increase in total distance covered compared to baseline values, and a 13% increase compared to white chocolate.
While VO2max increased by 6% following the dark chocolate intervention compared to baseline, no statistically significant difference was observed compared to white chocolate.
Commenting on the potential mechanism(s) of action, Patel and co-workers proposed that endothelium-dependent effects related to the flavanol content of cark chocolate, and (-)-epicatechin in particular, may boost the production of nitric oxide (NO), a potent vasodilator.
“A caveat of the present study was that flavanol and NO were not directly measured thus the causation of the observed effects is speculated around flavanol and NO,” they wrote.
Source: Journal of the International Society of Sports Nutrition
2015, 12:47 doi:10.1186/s12970-015-0106-7
“Dark chocolate supplementation reduces the oxygen cost of moderate intensity cycling”
Authors: R.K. Patel, J. Brouner, . Spendiff