A March 2021 study by University of Birmingham said,
"We found that drinking flavanol-rich cocoa can be an effective dietary strategy to reduce temporary impairments in endothelial function following mental stress and also improve blood flow during stressful episodes”.
"Flavanols are extremely common in a wide range of fruit and vegetables. By utilizing the known cardiovascular benefits of these compounds during periods of acute vascular vulnerability (such as stress) we can offer improved guidance to people about how to make the most of their dietary choices during stressful periods."
"Our findings are significant for everyday diet, given that the daily dosage administered could be achieved by consuming a variety of foods rich in flavanols - particularly apples, black grapes, blackberries, cherries, raspberries, pears, pulses, green tea and unprocessed cocoa. This has important implications for measures to protect the blood vessels of those individuals who are more vulnerable to the effects of mental stress,"