Consuming a cocoa drink rich in flavanols can mitigate the negative effects of high-fat foods on the vascular system during stress.
This research emphasizes the potential of high-flavanol cocoa to enhance vascular function and maintain cardiovascular health during stressful periods, offering a dietary strategy to combat the impacts of stress and poor nutrition.
Flavanol-Rich Cocoa and Cardiovascular Protection
New research reveals that a flavanol-rich cocoa drink can help protect the body’s vascular system from the effects of stress, even after consuming high-fat foods.
The food choices we make during stressful times can significantly impact cardiovascular health. A study from the University of Birmingham previously showed that high-fat foods can impair vascular function and reduce oxygen delivery to the brain. However, flavanols—natural compounds abundant in cocoa and green tea—can support vascular health during periods of everyday stress.
Combating Stress With Cocoa
Building on these findings, the same research team has now demonstrated that drinking high-flavanol cocoa alongside a fatty meal can mitigate some of the harmful effects of fatty foods and stress on the vascular system.
The research was published today (November 18th) in the journal Food and Function.
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.”
Understanding Flavanols and Their Health Benefits
Rosalind Baynham, first author on the paper, explained: “Flavanols are a type of compound that occur in different fruits, vegetables, tea, and nuts including berries and unprocessed cocoa. Flavanols are known to have health benefits, particularly for regulating blood pressure and protecting cardiovascular health.
“We took a group of young healthy adults and gave them two butter croissants with 10 g salted butter, 1.5 slices of cheddar cheese, and 250 ml whole milk as breakfast, and either a high-flavanol cocoa or a low-flavanol cocoa drink. Following a rest period, we asked the participants to complete a mental maths test which increased in speed for eight minutes, alerting them when they got an answer wrong. During the 8-minute rest period and 8-minute mental maths test, we measured forearm blood flow, cardiovascular activity, and prefrontal cortex (PFC) tissue oxygenation. We also measured vascular function using Brachial Flow-mediated dilatation (FMD), which is a prognostic measure for future risk of cardiovascular disease. This stress task-induced significant increases in heart rate and blood pressure, similar to the stress you may encounter in daily life.”
The cocoa beverages were prepared by dissolving 12 g cocoa powder into 250 ml of whole milk. The low-flavanol powder was an alkalized cocoa powder that was processed to reduce total flavanols to 5.6 mg per serving; and the high-flavanol cocoa powder was a non-alkalized powder, delivering 695.0 mg total flavanols per serving. Alkalization is a process typically used in chocolate making to enhance flavor, but unfortunately it reduces the amount of flavanols.
Key Findings: Flavanols and Vascular Protection
The team confirmed that consuming fatty foods with the low-flavanol drink when mentally stressed reduced vascular function (by 1.29% FMD) and lasted up to 90 minutes after the stressful event was over.
The findings also showed that the cocoa drink high in flavanols was effective at preventing the decline in vascular function following stress and fat consumption. Brachial flow-mediated dilatation was significantly higher following high-flavanol cocoa compared to low-flavanol cocoa 30 and 90 minutes after the stressful period.
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.
Practical Applications and Flavanol Intake Recommendations
Dr. Catarina Rendeiro, Assistant Professor in Nutritional Sciences at the University of Birmingham, added: “This research shows that drinking or eating a food high in flavanols can be used as a strategy to mitigate some of the impact of poorer food choices on the vascular system. This can help us make more informed decisions about what we eat and drink during stressful periods.”
In the supermarket look for a minimally processed cocoa powder, and if cocoa isn’t quite your beverage of choice, there are other ways you can get a higher dose of flavanols, such as green tea, black tea, and berries. Recent published guidelines for flavanol intake recommend between 400 to 600 mg/day, which can be achieved for example, by consuming two cups of black or green tea, or a combination of berries, apples, and high-quality cocoa.
Stress, Modern Life, and Small Lifestyle Changes
Jet Veldhuijzen van Zanten, Professor of Biological Psychology at the University of Birmingham, and author of this paper added: “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. 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.”
Reference: “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” by Rosalind Baynham, Jet J. C. S. Veldhuijzen van Zanten and Catarina Rendeiro, 18 November 2024, Food & Function.
DOI: 10.1039/D4FO03834G
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4 Comments
I’m normally very critical, and I will try hard to be, but this was good. It’s a small study of 23 people, with a reasonably simple hypothesis. I liked to see the quantitative difference between the alkalized dutched cocoa and their high-flavanol cocoa, when I had previously seen claims that alkalizing only reduces flavanols by about half (“Antioxidant Activity and Polyphenol and Procyanidin Contents of Selected Commercially Available Cocoa-Containing and Chocolate Products in the United States”, Journal of Agricultural and Food Chemistry, May 2006, Hershey-funded), while in this case it was actually a couple orders of magnitude. I liked that it showed different observable physical reactions in participants very quickly, within an hour. Cocoa is a commodity, and eating it is a change or intervention anyone can make easily and deliciously, without patents or marketing or prescriptions. Studies like this should attract further research. But mainly it was fun, and I’m interested.
The study lacked a control group, so it isn’t especially scientific, but oddly a great deal of work still went into it. Barry Callebaut provided the cocoa powders, so it could read as a commercial for their high-flavanol cococa, but the provider is only mentioned twice in the study and not even once in this article. The study was funded by the British government, which has conflicts of interest, but the cocoa was Swiss and the UK doesn’t re-export much cocoa, so maybe they only wanted to know because they eat a lot of chocolate. High levels of heavy metals have been found in cocoa, and that wasn’t tested for, but I don’t know how quickly ingesting them will affect a person. The headline is absolutely terrible; nothing here was cured, and the high flavanols only had a temporary effect on one small risk of a high-fat diet. But yeah, fun little yet in-depth study. Thanks University of Birmingham, and to the researchers, and even thanks to Callebaut for not pushing this like an advertisement so I might even buy some undutched high-flavanol cocoa.
It’s difficult to tell if the work was done well. It is predicated on a lot of previous results, with only the one referring to the fat study mentioned. Several questions exist about that study, and other conditions regarding carbohydrates, proteins, etc remain. Doesn’t mean this study is wrong, but the reporting makes it difficult to know.
And further questions remain about the effect of compounds like caffeine, usually found in cocoa, green tea, etc. Was that accounted for?
So I don’t think the reporting here was grand (although I’ve seen far worse) I just am not fully comfortable with the either experimental design or conclusions based on lack of critical foundational details.
I completely agree. I don’t think the study was done especially well. A study without a control is silly. Just means the design is fundamentally flawed. A control group could have helped eliminate a lot of variables. That said, they still did do a great deal of work, and it was still interesting.
The study did note the carbohydrates, proteins, and caffeine variations in the high-flavanol cocoa versus the low-flavanol cocoa. The undutched cocoa had more fiber, half the carbohydrates, and very slightly less caffeine and fat and calories. For a flavanol study, those variables would have to be eliminated by providing some kind of pure-flavanol supplement, but this was a cocoa study.
Correction: It was the dutched/alkalized cocoa that had twice the fiber, half the carbohydrates, slightly less caffeine and fat and calories.