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A new study offers evidence that a daily cocoa extract supplement may offer protection against age-related heart disease.
Data from nearly 600 older adults found that participants who took this kind of supplement had significantly lower levels of an inflammation biomarker tied to age-related heart disease — suggesting cocoa has anti-inflammatory properties that may translate into heart-protective benefits, researchers say.
Cocoa Supplements May Combat Inflammation Tied to Aging
In a large initial investigation called COSMOS (the Cocoa Supplement and Multivitamin Outcomes Study), researchers randomly assigned more than 20,000 adults to receive either 500 milligrams (mg) of cocoa extract or a placebo (a dummy pill).
The study was supported in part by the supplement manufacturer Mars Edge and the pharmaceutical company Pfizer; each contributed materials and funding but weren’t involved in the trial design or analysis.
After an average follow-up of about 3.5 years, the results showed that participants who took cocoa supplements had a 27 percent lower rate of heart disease deaths. But there wasn’t a significant reduction in overall cardiovascular crises like heart attack and stroke — prompting the researchers to dig deeper.
For the current study, the team looked at a subset of data from nearly 600 older adults to see whether the cocoa supplements would have any effect on five age-related biomarkers of inflammation.
They found that a marker tied to greater heart disease risk — called high-sensitivity C-reactive protein, or hsCRP — significantly decreased in participants who took a daily cocoa extract supplement.
The findings suggest cocoa supplements may encourage a decrease in “inflammaging,” or inflammation linked to aging, says the corresponding study author Howard Sesso, ScD, MPH, an associate director of preventive medicine and an associate epidemiologist at Brigham and Women’s Hospital in Boston.
Antioxidants Called Flavanols May Benefit Heart Health
The results add to a growing body of evidence suggesting that flavanols — antioxidants found naturally in foods and beverages like tea, berries, red wine, nuts, spices, and yes, cocoa — may offer meaningful anti-inflammatory benefits, including for the heart.
Previous research has indicated that dark chocolate may decrease the risk of high blood pressure and a blood clot condition known as venous thromboembolism in people of European ancestry, though the finding wouldn’t necessarily be generalizable to a broader population.
As another example, one analysis found that participants who ate dark chocolate or took cocoa supplements for at least four weeks had lower blood pressure, cholesterol, and fasting blood glucose levels.
Should You Try Cocoa Extract Supplements at Home?
The 500 mg cocoa flavanol supplement used in the COSMOS trial aligns with the daily suggested amount (400 to 600 mg) recommended by the Academy of Nutrition and Dietetics to support cardiometabolic health — though that recommendation is based on food sources of flavanols rather than supplements.
Unfortunately, it’s not easy to get that much flavanol from standard chocolate or cocoa products on the market, Dr. Sesso says, because processing cocoa beans strips much of their flavanol content.
“Cocoa flavanol content is not found on food labels, but cocoa powder may be more likely to have modest amounts,” he says. “There are some cocoa extract supplements on the market, but they are not mainstream, so I would recommend initially focusing on flavanols as part of a broad plant-based healthy diet.”
People with a known allergy to cocoa shouldn’t take cocoa extract supplements. They also wouldn’t be appropriate for someone who is particularly sensitive to caffeine, because cocoa contains modest amounts of the similar mild stimulant called theobromine, Sesso explains.
What Does the Study Reveal About Cocoa Flavanols and Age-Related Disease?
The study design offers strengths in that it pulls from the COSMOS trial, which was large-scale, randomized, and double-blind — meaning the participants didn’t know which supplement they were taking. But as the researchers underscore, the findings were limited to older adults who remained healthy during the trial, and did not investigate changes in inflammation markers that might have led to heart disease.
Overall, there’s not enough conclusive evidence yet to determine exactly how cocoa extract products affect heart health, and there’s more investigation to be done, says Douglas Vaughan, MD, a professor of medicine in cardiology and the director of the Potocsnak Longevity Institute, which focuses on studying the biological changes associated with aging, at the Northwestern University Feinberg School of Medicine in Chicago.
“The research looks at biomarkers mostly related to inflammation, so that’s a limitation,” Dr. Vaughan says. “You can’t draw conclusions that this has an effect on aging, as they didn’t actually measure changes in aging of the vascular or other organ systems that might be reflective of a change in biological age, so it’s a limited perspective.”
For Longevity, Focus on Overall Diet, Exercise, and Stress Reduction
The study suggests that a nutritious and flavanol-rich diet may support the heart and healthy aging.
“It is most important to focus on a healthy dietary pattern first, along with other known lifestyle and clinical risk factors for cardiovascular disease,” says Sesso. “We already have many tools to help prevent cardiovascular disease. No single food is most important; cocoa flavanols should be part of a broader healthy pattern of diet and other lifestyle factors.”
At the Human Longevity Lab at Northwestern, Vaughan says recommendations for extending lifespan and healthspan focus on evidence-based strategies: “One, exercise regularly. Two, get your weight to an optimal level, whatever that takes. And three, try to reduce stress in your life.”
EDITORIAL SOURCES
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Resources
Li S et al. Effects of 2-year Cocoa Extract Supplementation on Inflammaging Biomarkers in Older US Adults: Findings From the COcoa Supplement and Multivitamin Outcomes Study Randomised Clinical Trial. Age and Ageing. September 2025.
Sesso HD et al. Effect of Cocoa Flavanol Supplementation for the Prevention of Cardiovascular Disease Events: The COcoa Supplement and Multivitamin Outcomes Study (COSMOS) Randomized Clinical Trial. American Journal of Clinical Nutrition. June 2022.
Ciumărnean L et al. The Effects of Flavonoids in Cardiovascular Diseases. Molecules. September 2020.
Yang J et al. Dark Chocolate Intake and Cardiovascular Diseases: A Mendelian Randomization Study. Science Reports. January 2024.
Arisi TOP et al. Effects of cocoa consumption on cardiometabolic risk markers: meta-analysis of randomized controlled trials. Nutrients. June 2024.
Crowe-White KM et al. Flavan-3-ols and Cardiometabolic Health: First Ever Dietary Bioactive Guideline. Advances in Nutrition. November 2022.
Emily Kay Votruba has copyedited and fact-checked for national magazines, websites, and books since 1997, including Self, GQ, Gourmet, Golf Magazine,Outside, Cornell University Press, Penguin Random House, and Harper's Magazine. Her projects have included cookbooks (Padma Lakshmi's Tangy Tart Hot & Sweet), self-help and advice titles (Mika Brzezinski's Know Your Value: Women, Money, and Getting What You're Worth), memoirs (Larry King's My Remarkable Journey), and science (Now You See It: How the Brain Science of Attention Will Transform How We Live, Work, and Learn, by Cathy Davidson). She started freelancing for Everyday Health in 2016.
Cristina Mutchler is an award-winning journalist with more than a decade of experience covering health and wellness content for national outlets. She previous worked at CNN, Newsy, and the American Academy of Dermatology. A multilingual Latina and published bilingual author, Cristina has a master's degree in Journalism from the E.W. Scripps School of Journalism at Ohio University.
