Cocoa only lowers blood pressure and blood stiffness when it’s high, according to a new study from the University of Surrey.
Cocoa flavanols have previously been found to reduce blood pressure and blood stiffness as much as some blood pressure medications. However, the effectiveness of flavanols in everyday life to lower blood pressure has remained unknown, as previous studies in this area have been conducted in tightly controlled experimental settings.
New research from Surrey eases concerns that cocoa as a treatment for high blood pressure may pose health risks by lowering blood pressure when it is not elevated, paving the way for its use in clinical practice
In the first study of its kind, the researchers set out to investigate the use of flavanols, a compound found in cocoa, to reduce blood pressure and blood stiffness in people outside of the clinical setting.
High blood pressure and stiff arteries increase the risk of heart disease and stroke, so it is crucial that we investigate innovative ways to treat these conditions.
Before we even consider introducing cocoa into clinical practice, we need to test whether the results previously reported in laboratory settings translate safely into real-world settings, with people going about their daily lives.”
Christian Heiss, Professor of Cardiovascular Medicine, University of Surrey
Over several days, eleven healthy participants consumed, on alternate days, either six cocoa flavanol capsules or six placebo capsules containing brown sugar. Participants were given an upper arm blood pressure monitor and a finger clip that measured pulse wave velocity (PWV) which measures levels of arterial stiffness.
Blood pressure and PWV measurements were taken before consumption of the capsules and every 30 minutes after ingestion for the first three hours, and then every hour for the remaining nine hours. The researchers found that blood pressure and blood stiffness were only reduced in participants if it was high, and there was no effect when blood pressure was low in the morning.
Significantly, the effects were also identified, for the first time, eight hours after consuming the cocoa. The researchers believe that this second peak may be due to how bacteria in the gut metabolize the flavanols in cocoa.
Professor Heiss added:
“The positive impact that cocoa flavanols have on our cardiovascular system, in particular blood vessel function and blood pressure, is undeniable. Doctors often fear that some blood pressure pills may lower blood pressure too much arterial some days.
“What we found indicates that cocoa flavanols only lower blood pressure if it is elevated. Working with participants’ personal health technologies showed us how variable blood pressure and blood stiffness can be from day to day and shows the role of personal health monitors in development. and implement effective personalized care.”
Source:
Journal reference:
Bapir, M., et al. (2022) Assessing the variability of vascular response to cocoa with personal devices: a series of n-of-1 randomized double-blind trials. Frontiers in nutrition. doi.org/10.3389/fnut.2022.886597.