Data published in Food and Function indicated that concomitant ingestion of 150 mg of the cocoa flavanol (−)-epicatechin with a high fat meal 1.5 hours before a mental stress task led to improvements in flow-mediated dilation (FMD), a measure of a blood vessel’s healthy ability to relax, 90 minutes after the stress test. FMD was impaired in the low-dose flavanol comparison group.
“To our knowledge, this is the first study to show that high-flavanol cocoa can attenuate the stress-induced decline in brachial FMD following a high-fat meal,” wrote the authors, from the University of Birmingham’s School of Sport, Exercise and Rehabilitation Sciences.
“Given the prognostic value of FMD for future risk of CVD [cardiovascular disease], these findings are clinically relevant, particularly given the documented prevalence of stress and the trend towards increased consumption of high-fat foods during periods of heightened stress,” they added.
“This work has relevance for application in everyday diet, as the administered dose of flavanols could be achieved through consumption of, for instance, 2 cups of green tea, 5.5 tbsp of unprocessed cocoa or 300 g of berries.”
Cocoa’s benefits
The study adds to the growing body of science around the potential health benefits of cocoa. To date, most of this has revolved around potential cardiovascular benefits of the flavanols (also known as flavan-3-ols or catechins), and particularly the monomeric flavanol (-)epicatechin. Additional studies have reported potential benefits for skin and brain health.
There are also reports in the literature that cocoa-rich chocolate can improve measures of stress. For example, a 2009 study published in the Journal of Proteome Research indicated that consuming 40 g of dark chocolate per day for two weeks led to reductions in the stress hormone cortisol and catecholamines.
Barry Callebaut has also funded studies in this area, with results of a 2013 randomized, double-blind study by scientists from the Swinburne University of Technology in Australia indicating that cocoa flavanols may keep you calmer and content without affecting cognitive performance (Journal of Psychopharmacology, Vol. 27, pp. 451-458).
Study details
Twenty-three young healthy adults (aged 18-45) were recruited to participate in the randomized, counterbalanced, double-blinded, crossover, postprandial intervention study.
The participants were all given a high fat meal with (56.5 g of fat) with a low- (5.6 mg of (−)-epicatechin) or high-flavanol (150 mg (−)-epicatechin and 695 mg total flavanols per serving) cocoa drink. This occurred 90 minutes before an 8-minute mental stress task (a mental arithmetic test which increased in speed for eight minutes).
Results showed that mental stress after the fatty meal and low-flavanol drink was associated with a 1.3% reduction in FMD, but the high-flavanol drink prevented the declines in vascular function.
The data also showed that high-fat food consumption plus stress led to an attenuation in cerebral oxygenation in the pre-frontal cortex. However, cocoa flavanols did not improve cerebral oxygenation or impact mood.
“In summary, flavanols can counteract declines in endothelial function induced by consuming fat in the context of stress but do not impact cerebral oxygenation,” the researchers wrote. “These findings can have important implications for flavanol-rich dietary choices to protect the vasculature from stress.”
Source: Food and Function
2024,15, 11472-11490, doi: 10.1039/D4FO03834G
“Cocoa flavanols rescue stress-induced declines in endothelial function after a high-fat meal, but do not affect cerebral oxygenation during stress in young, healthy adults”
Authors: R. Baynham et al.
