COCOA flavanol supplements have been shown to lower levels of inflammation linked to ageing and cardiovascular disease, according to an ancillary study of the large COSMOS trial. Researchers found that daily cocoa extract reduced hsCRP, a key inflammatory biomarker, by 8.4% each year.
The findings add to growing evidence that plant-based compounds can play a role in managing age-related chronic inflammation, known as inflammaging. Previous studies have suggested that flavanol-rich foods such as cocoa, tea, grapes, and berries may support cardiovascular health, but this is the largest trial to link cocoa extract supplementation with reductions in specific inflammatory markers.
Investigators at Mass General Brigham and Augusta University analysed blood samples from 598 participants in the COSMOS study, which originally enrolled over 21,000 older adults between 2014 and 2020. The mean age of participants was 70 years, with roughly half being female. Results showed that individuals receiving cocoa extract supplements experienced an annual reduction of 8.4% in hsCRP levels compared to placebo, while other inflammatory markers remained largely stable. An unexpected increase of 6.8% in interferon-γ, an immune-related cytokine, was also observed. Importantly, the parent COSMOS trial previously reported a 27% reduction in cardiovascular death among those taking cocoa extract, raising the likelihood that these anti-inflammatory effects contribute to its heart-protective benefits.
For clinical practice, these results highlight a potential role for targeted nutritional strategies in reducing systemic inflammation associated with cardiovascular risk. Cocoa flavanol supplementation is not a substitute for diet or lifestyle modification, but it may be a useful adjunct to conventional prevention approaches in older adults. Longer-term trials and mechanistic studies are now required to clarify how flavanols interact with immune regulation and to determine whether supplementation can prevent other chronic conditions associated with ageing. These findings also reinforce the value of plant-based foods in supporting healthy ageing and cardiovascular care.
Reference
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. 2025;54(9):afaf269.
