Drinking cocoa or green tea may mitigate stress-induced heart risks from fatty foods, study finds

A recent study published in the journal Food & Function found that consuming cocoa or green tea rich in flavanols can mitigate the negative effects of stress and fatty foods on vascular health. Conducted by researchers at the University of Birmingham, the study revealed that drinking flavanol-rich cocoa alongside a fatty meal helps maintain blood vessel function during periods of stress, effectively counteracting some of the harmful impacts of poor dietary choices.

"We know that when people are stressed, they tend to gravitate towards high-fat foods," said Dr. Catarina Rendeiro, assistant professor in nutritional sciences at the University of Birmingham. "This study shows that drinking or eating food high in flavanols can be used as a strategy to mitigate some of the effects of poor dietary choices on the vascular system."

The Sun, The Independent, Sky News, and Science Daily were among the websites that reported on the study.

Flavanols are naturally occurring compounds found in various fruits, vegetables, teas, and nuts, including berries and unprocessed cocoa. They are known for their health benefits, particularly in regulating blood pressure and protecting cardiovascular health.

In the study, 23 healthy adults were given a high-fat breakfast consisting of two butter croissants with 10 grams of salted butter, one and a half slices of cheddar cheese, and 250 milliliters of whole milk. After the meal, participants were randomly assigned to consume either a high-flavanol cocoa drink containing 695 milligrams of flavanols or a low-flavanol cocoa drink containing 5.6 milligrams of flavanols.

Following an eight-minute rest period, participants underwent a mental math test designed to induce stress. The test increased in difficulty, and an alarm sounded when incorrect answers were given. "Each time the participants got a wrong answer, they were notified," according to the release. During the rest and stress phases, scientists measured participants' blood flow in the forearm, cardiovascular activity, and prefrontal cortex oxygen saturation.

The stress task led to significant increases in heart rate and blood pressure, similar to the stress encountered in daily life. "This stress task induced significant increases in heart rate and blood pressure, similar to the stress you may encounter in daily life," noted Rosalind Baynham, another author on the study.

Results showed that participants who consumed the low-flavanol cocoa experienced a significant decline in vascular efficiency, with reduced blood vessel function lasting up to 90 minutes after the stressful event. In contrast, those who consumed the flavanol-rich cocoa maintained vascular function even under stress, with significant improvements in blood flow observed at 30 and 90 minutes after the stressful period.

"The high-flavanol drink prevented a similar decline in blood vessel function," reported the researchers. "This can help us make more informed decisions about what we eat and drink during stressful periods," added Dr. Rendeiro.

Jet Veldhuijzen van Zanten, Professor of Biological Psychology at the University of Birmingham, emphasized the importance of these findings: "Modern life is stressful, and the impact of stress on our health and the economy has been well documented, so any changes we can make to protect ourselves from some of the symptoms of stress is positive."

While the study used cocoa drinks as the source of flavanols, these beneficial compounds are abundant in other foods and beverages as well. "Flavanols are compounds found in various fruits, vegetables, teas, and nuts, including berries and unprocessed cocoa," explained Baynham. For those who prefer alternatives to cocoa, Dr. Rendeiro suggests consuming green tea, black tea, or berries to achieve a higher dose of flavanols.

Experts recommend a daily intake of 400 to 600 milligrams of flavanols, which can be achieved by drinking two cups of black or green tea or by combining berries, apples, and high-quality, minimally processed cocoa. "For those who tend to reach for a treat when stressed or depend on convenient food because they work high-pressure jobs or are time-poor, incorporating some of these small changes could make a real difference," suggested van Zanten.

The findings highlight the potential of flavanol-rich foods and beverages to counteract some of the negative effects of stress and fatty foods on cardiovascular health. By making informed dietary choices, individuals may be able to protect their vascular function during stressful periods.

"This can help us make more informed decisions about what we eat and drink during stressful periods," said Dr. Rendeiro. "Incorporating flavanol-rich foods into the diet can be used as a strategy to mitigate some of the impact of poorer food choices on blood vessels."

This article was written in collaboration with generative AI company Alchemiq