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Cardiovascular & heart health effects of cocoa flavanols

Flavanol intake in the diet has been shown by multiple studies to improve cardiovascular function

3D illustration of heart inside male body

Cardiovascular health and the prevention, or delayed onset, of cardiovascular diseases and related deaths are major global health challenges. While often positioned as an age-related concern, healthy blood vessel function and a healthy heart are critical for people of all ages. Today, we know cardiovascular health impacts our physical and mental performance, as well as our fitness and sense of well-being. There's ample evidence we can preserve and improve cardiovascular health throughout all life stages with life-style choices, like physical exercise, weight management, stress management, and a healthy diet.

Cocoa flavanols’ impact on cardiovascular heath

Various physiological changes can be used as markers of the impact of aging on the body, including the cardiovascular system. To date, multiple studies have demonstrated a beneficial effect of cocoa flavanol intake on several of these markers. For example, blood pressure often increases with age. Controlling blood pressure is also a well-established way to reduce the risks associated with cardiovascular disease, for example by eating a healthy diet rich in fruit and vegetables and low in salt. Flavanol intake in the diet has been shown by multiple studies to lower blood pressure by a significant amount and could therefore have a protective effect on the cardiovascular system.

Cocoa flavanols also have a beneficial effect on the elasticity of the blood vessels. As we age, blood vessels tend to stiffen, they damage more easily and delivery of oxygen to the tissues is compromised. Cocoa flavanol intake improves performance in these markers increasing the dilation of blood vessels in response to blood flow and improving blood supply and oxygen delivery to tissue.

Several cardiovascular diseases involve a process called atherosclerosis, which causes fatty plaques to narrow the arteries to organs like the heart and brain. Not only can cocoa flavanols help maintain healthy cholesterol in the blood that leads to these fatty build-ups over time, some studies have shown that it may improve the body’s ability to repair damaged vessels (by influencing the activity of endothelial progenitor cells/circulating angiogenic cells). A diet high in flavanols also reduces the reactivity of platelets, reducing their capacity to form blood clots. These can form as a result of atherosclerosis and can block critical arteries, causing heart attacks and strokes. 

Since the 1990s, we've published over 50 peer-reviewed research papers that show various beneficial effects of flavanol intake on health. While we're still investigating the specific molecular mechanisms behind these phenomena, we know flavanols are pleiotropic, meaning they exert a range of distinct physiological effects.

Our research on cardiovascular health

It's important to know whether people who consume a diet high in flavanols are less likely to develop cardiovascular disease over time. A large clinical dietary intervention is currently underway to investigate this. The study, called COSMOS, is based at Brigham and Women's Hospital (an affiliate of Harvard Medical School) and the Fred Hutchinson Cancer Research Center. Over 21,000 healthy men and women across the U.S. take a daily supplement of cocoa flavanols (600 mg/day). Results of the study will be available in 2021.

There have already been promising results. Research from an international team from the University of Reading, Cambridge University, the University of California Davis, and Mars Edge found that consuming a diet including flavanol-rich foods and drinks, including tea, apples or berries, was linked to lower blood pressure.

The COSMOS trial builds on a key milestone in our cardiovascular research program—a pan-European research project called FLAVIOLA. Amongst other things, the FLAVIOLA group looked at the effects of cocoa flavanol intake on cardiovascular risk scores and markers such as blood pressure, blood cholesterol and flow-mediated vasodilation.

The COSMOS trial
Cocoa flavanols and chocolate