You may have heard people say cacao "opens the heart." For some, that's a spiritual expression. For others, it raises an interesting question: could cacao also support the physical heart and circulatory system?
Over the past few decades, researchers have been exploring how the natural compounds found in cacao affect blood vessel function and circulation. Their findings suggest that cacao may support healthy circulation through well understood biological pathways, offering a scientific perspective on why cacao has been valued for centuries.
So what is it about cacao that has scientists so interested?
It comes down to a group of naturally occurring plant compounds called flavanols. Among commonly eaten foods, cacao is one of the richest natural sources of flavanols. One flavanol in particular, epicatechin, has been studied extensively for its effects on blood vessel function.
Once absorbed into the bloodstream, epicatechin appears to encourage the lining of our blood vessels, known as the endothelium, to produce more nitric oxide (NO).
Nitric oxide acts like a messenger. It tells the muscles in our blood vessel walls to relax.
When blood vessels are more relaxed and flexible, blood can flow through them way more easily. This reduces resistance within the circulatory system and helps explain why cacao flavanols have been associated with improvements in blood vessel function and modest reductions in blood pressure. (1)
What Does the Research Say?
Improved Blood Vessel Function
The Flaviola Health Study found that healthy adults who consumed cocoa flavanols daily for one month showed improved blood vessel function, modest reductions in blood pressure, and improvements in cholesterol markers. (2)
Lower Blood Pressure
A 2017 Cochrane review of 18 clinical trials concluded that flavanol-rich cocoa can produce modest reductions in blood pressure, particularly in people who already have elevated blood pressure. (1)
Supporting Healthy Circulation During Stress
Mental stress can temporarily reduce blood vessel function. In one clinical trial, the participants who consumed cocoa flavanols maintained healthier vascular function after acute mental stress, with benefits still evident 90 minutes later. (3)
Long Term Heart Health
The largest study to date, the COSMOS trial, followed more than 21,000 older adults for 3.6 years. While the reduction in cardiovascular events did not reach statistical significance, cardiovascular deaths were 27% lower among participants taking cocoa flavanols, with stronger effects among those who took them consistently. The researchers described these findings as promising, but not yet conclusive. (4)
Healthy Ageing and Brain Health
Researchers are also investigating whether the vascular benefits of cocoa flavanols may extend to healthy brain ageing. As healthy circulation is essential for delivering oxygen and nutrients to the brain, maintaining healthy blood vessel function may become increasingly important as we age, although more research is needed to confirm these effects. (6,7)
Why Processing Method Actually Matters
Whether it's dark chocolate, cocoa powder or ceremonial cacao, they all begin with the same cacao bean, Theobroma cacao. The biggest difference is how that bean is processed.
Flavanols are naturally delicate compounds. Heavy roasting and alkalising (Dutch processing) can substantially reduce the amount that remains in the finished product. As a result, minimally processed cacao is generally expected to retain more of its naturally occurring flavanols.
So, Why Choose Minimally Processed Cacao?
Current research suggests that the naturally occurring flavanols in cacao may support healthy blood vessel function and circulation. Clinical studies have shown modest improvements in blood pressure and vascular function, while research into long term cardiovascular protection is promising, however, not yet conclusive.
Since processing influences flavanol content, choosing a minimally processed cacao may help preserve more of these naturally occurring plant compounds.
Cacao's reputation as a "heart opener" turns out to have some real chemistry behind it. While it's not a cure or a substitute for medical care, it may be one small way to support your cardiovascular health as part of an overall healthy lifestyle.
References
1. Effect of cocoa on blood pressure
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD008893.pub3/full
2. Cocoa flavanol intake improves endothelial function and Framingham Risk Score in healthy men and women: a randomised, controlled, double-masked trial: the Flaviola Health Study
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594054
3. Cocoa Flavanols Improve Vascular Responses to Acute Mental Stress in Young Healthy Adults
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065749
4. Effect of cocoa flavanol supplementation for the prevention of cardiovascular disease events: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9170467
5. COSMOS Trial Results. Brigham and Women's Hospital / Mass General Brigham. https://cosmostrial.org/results
6. Cocoa flavanols and brain perfusion
https://pubmed.ncbi.nlm.nih.gov/16794460
7. Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans
https://pubmed.ncbi.nlm.nih.gov/18728792
This article is for informational purposes only and is not medical advice. Speak with a healthcare provider before making changes related to a cardiovascular condition or medication regimen.