Sipping a cup of unsweetened hot cocoa may be a good idea this winter as a new study has revealed that the flavanol-rich cocoa drink can protect the body's vascular system from the ill effects of stress, even after having high-fat foods.

Flavanols that naturally occur in different fruits, vegetables, tea, and nuts like berries and unprocessed cocoa are packed with several health benefits, specifically for managing blood pressure and protecting heart health .

The research published in the Journal Food and Function shows that drinking high-flavanol cocoa along with a fatty meal can reduce some of the harmful effects of fatty foods and stress on the vascular system.

Dr. Catarina Rendeiro, Assistant Professor in Nutritional Sciences at the University of Birmingham , and leading author said: “We know that when people are stressed, they tend to gravitate towards high-fat foods. We have previously shown that fatty food can impair the body’s vascular recovery from stress. In this study, we wanted to see if adding a high-flavanol food to the fatty meal would alleviate the negative impact of stress in the body.”

A previous research from the University of Birmingham showed that high-fat foods can impair vascular function and reduce oxygen delivery to the brain. However, flavanols—abundant foods like cocoa and green tea can support vascular health during stressful times.

A study was conducted involving healthy young adults to investigate the effects of high-flavanol cocoa on cardiovascular and cognitive stress responses . Participants were given a breakfast of butter croissants, cheddar cheese, and whole milk, followed by either a high-flavanol or low-flavanol cocoa beverage. The high-flavanol drink contained 695 mg of flavanols from non-alkalized cocoa, while the low-flavanol version, made from alkalized cocoa, had just 5.6 mg of flavanols.

After a rest period, participants completed an eight-minute mental math test designed to raise stress levels, during which forearm blood flow, heart rate, blood pressure, and oxygenation in the brain’s prefrontal cortex were measured. Vascular function was also assessed using Brachial Flow-Mediated Dilation (FMD), a marker for cardiovascular health. The findings highlighted that stress from the test triggered significant cardiovascular responses, akin to real-life stress.

The team found out that having fatty foods with the low-flavanol drink when stressed can reduce vascular function, the effects of which could last up to 90 minutes after the stressful event was over.

The cocoa drink high in flavanols could effectively prevent decline in vascular function following stress and fatty diet consumption.

The team had also found in their previous work, that eating high-fat foods attenuated cerebral oxygenation in the pre-frontal cortex, during stress. However, cocoa flavanols did not improve cerebral oxygenation or impact mood.

Eating or drinking foods rich in flavanols can thus reduce impact of some faulty diet choices on the vascular system and reduce risk of blood pressure and heart disease.

Flavanol-rich foods include dark chocolate, cocoa, green tea, and berries. These foods may support cardiovascular health and improve blood flow.