Cocoa flavanols

THURSDAY, Aug. 28, 2025 -- Long-term cocoa extract supplementation does not reduce the risk for incident hypertension but does reduce hypertension incidence among those with normal systolic blood pressure (BP) at baseline, according to a study published online Aug. 20 in Hypertension . Rikuta Hamaya, M.D., from Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues examined the role of cocoa flavonols on incident hypertension in a large-scale, long-term randomized clinical trial. A total of 21,442 women aged 65 years and older and men aged 60 years and older were randomly assigned to receive cocoa extract and a multivitamin or placebos, which did not include any bioactive compounds. The effect of cocoa extract on incident hypertension was examined in 8,905 participants free from baseline hypertension. The researchers found that cocoa extract supplementation had no significant effect on incident hypertension in an intention-to-treat analysis during a median follow-up of 3.4 years, with incidence rates of 7.1 and 7.4 per 100 person-years in the cocoa and placebo groups, respectively (hazard ratio [HR], 0.96; 95 percent confidence interval [CI], 0.88 to 1.05). In subgroup analyses, the incidence of hypertension was reduced with cocoa extract supplementation among individuals with baseline systolic BP <120 mm Hg but not among those with systolic BP of 120 to 139 mm Hg (HR, 0.76 [95 percent CI, 0.64 to 0.90]; HR, 1.05 [95 percent CI, 0.93 to 1.18]). At year 2 after random assignment, the effect among those with baseline systolic BP <120 mm Hg became evident. "This finding raises the hypothesis that cocoa flavanols may be more effective in preserving vascular health and preventing early blood pressure elevation, rather than lowering already-elevated blood pressure," the authors write. Two authors disclosed ties to Mars Edge and Pfizer. Abstract/Full Text (subscription or payment may be required)

Researchers are reporting new evidence on the effectiveness of cocoa flavanol supplements for cognition. In a randomized controlled clinical trial of 573 people, the researchers found that older adults who had unhealthy diets and took daily cocoa extract supplements containing 500 mg/day of cocoa flavanols experienced cognitive benefits. Cognitive benefits however were not seen in participants who already had healthy dietary patterns. Cocoa extract has shown a potential protective effect on cognition but randomized clinical trials in older adults have had inconsistent results. A new study of cognition in a randomized trial, known as the Cocoa Supplement and Multivitamin Outcomes Study (COSMOS), suggests that taking cocoa extract supplements containing 500 mg per day of cocoa flavanols had cognitive benefits for older adults who had lower habitual diet quality at the time of enrollment in the study. However, cognitive benefits were not found among participants who already had healthy dietary patterns at the start of the study. The study, conducted by researchers at Mass General Brigham, included 573 older adults who underwent detailed, in-person cognitive testing and is published online in The American Journal of Clinical Nutrition. Results from detailed neuropsychological assessments given over two years showed that daily cocoa extract supplementation, compared to placebo, had no overall benefits for global or domain-specific cognitive function. However, secondary analyses showed that participants with poor diet quality had cognitive benefits from taking the cocoa extract supplement. The findings from this study -- which was done among COSMOS participants who presented in-person for detailed cognitive testing -- are consistent with the results from an earlier study that used a web-based cognitive assessment given over the internet to a separately recruited set of COSMOS participants. COSMOS is an investigator-initiated large-scale, long-term clinical trial led by Brigham and Women's Hospital. More than 21,000 older women and men were enrolled across the United States to participate in this randomized, double-blinded, placebo-controlled study to test whether taking daily supplements of a cocoa extract or a common multivitamin reduces the risk for developing heart disease, stroke, cancer, and other important health outcomes. Analyses of the data from COSMOS continue to yield insights about the connections between supplements and human health. Funding statement: The COcoa Supplement and Multivitamin Outcomes Study (COSMOS) is supported by an investigator-initiated grant from Mars Edge, a segment of Mars dedicated to nutrition research and products, which included infrastructure support and the donation of study pills and packaging. Pfizer Consumer Healthcare (now Haleon) provided support through the partial provision of study pills and packaging. COSMOS is also supported in part by grants AG050657, AG071611, EY025623, and HL157665 from the National Institutes of Health, Bethesda, MD. The Women's Health Initiative (WHI) program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, U.S. Department of Health and Human Services through contracts 75N92021D00001, 75N92021D00002, 75N92021D00003, 75N92021D00004, 75N92021D00005. Neither Mars Edge nor Pfizer Consumer Healthcare provided input regarding data analyses, interpretation of results, or manuscript development.