A recent study published in June 2022 in the journal Frontiers in Nutrition suggests that Cocoa consumption could be as effective at reducing arterial stiffness and lowering blood pressure as some blood pressure medications.

Specifically, it is the flavanols found in Cocoa that provide the reported health benefits. Flavanols are an antioxidant and are commonly found in red wine, some berries, kale and tomatoes. Previous studies conducted in laboratory conditions have shown a link between consumption of Cocoa flavanols and blood pressure improvements. However, studies performed in airtight clinical conditions are not necessarily reflective of real-world results.

Scientists at the University of Surrey in England sought to test Cocoa’s impact on blood pressure and heart in a real-world setting, testing 11 healthy participants.

High blood pressure and arterial stiffness can increase a person’s risk of heart disease and strokes, so it is crucial that we investigate innovative ways to treat such conditions. Before we even consider introducing Cocoa into clinical practices, we need to test if the results previously reported in laboratory settings safely translate into real-world settings, with people going about their everyday lives.

Christian Heiss, Cardiovascular Medicine Professor, University of Surrey

The Study

Eleven participants were asked to consume six Cocoa flavanol capsules on Day One, followed by six placebo capsules on Day Two at the research facility, and alternately in this fashion for the remaining six days. They tracked their own blood pressure using a monitor on their upper arm, and arterial stiffness was tracked using a biometric pulse wave velocity (PWV) finger clip.

Measurements were taken:
• Before pill consumption
• Every 30 minutes for 3 hours post-consumption
• Every 60 minutes for the 9 hours following

The results of the 8-day study showed that consumption of Cocoa flavanols had a positive effect on reducing blood pressure and arterial stiffness. The researchers also noted that there were a couple of interesting points. Firstly, the cardiovascular health improvements were still visible eight hours post-Cocoa consumption. This second wave of benefits (appearing after the first benefits were noted three hours post-consumption) is speculated to be because of the delayed metabolism of the Cocoa flavanols by ‘good’ gut bacteria.

Secondly, the flavanols only reduced blood pressure readings in the participants who had high readings to begin with. Those with normal or low readings in the morning prior to taking the pill saw no change. 

The positive impact Cocoa flavanols have on our cardiovascular system, in particular, blood vessel function and blood pressure, is undeniable. Doctors often fear that some blood pressure tablets can decrease the blood pressure too much on some days.

What we have found indicates that Cocoa flavanols only decrease blood pressure if it is elevated. Working with participants’ personal health technologies showed us how variable blood pressure and arterial stiffness can be from day to day and shows the role of personal health monitors in developing and implementing effective personalised care.

Christian Heiss, Cardiovascular Medicine Professor, University of Surrey

While the study is short and was limited in its participants, the suggested benefits to heart health are promising and show potential for Cocoa to be the first course of treatment for those with mild hypertension. Much larger studies with more participants over a longer period of time are still required to confirm the findings.

It is important to note that the health benefits reported in the study result from the consumption of Cocoa flavanols in the form of pills, not sugary chocolate snacks. To consume Cocoa for its reported benefits to the heart, opt for pure Cocoa or dark chocolate with a high Cocoa content. A sugary chocolate bar is unlikely to improve one’s cardiovascular health.

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