Key chemical in dark chocolate may slow down ageing

11th December 2025 – By King’s College London

A common plant compound found in dark chocolate may help slow biological ageing, according to new research that includes data from TwinsUK.

The study, published today in Aging, compared levels of theobromine in people’s blood, with blood-based markers of biological ageing.

Biological age markers indicate how old your body seems based on its health and function, as opposed to the years you have lived. These markers are based on patterns of small ‘bookmarks’ on our DNA, called methylation, that change over the course of our lives.

Across two European cohorts, which included 509 individuals from TwinsUK and 1,160 from KORA, the research found that those who had higher theobromine circulating in their blood had a biological age that was lower than their actual age.

Using data from 509 individuals in the TwinsUK registry and 1,160 participants from the KORA cohort in Germany, the team compared blood levels of theobromine with biological ageing markers. They found that people with higher circulating theobromine tended to have a biological age younger than their actual age.

“Our study finds links between a key component of dark chocolate and staying younger for longer. While we’re not saying that people should eat more dark chocolate, this research can help us understand how everyday foods may hold clues to healthier, longer lives.”
— Professor Jordana Bell, senior author and Professor of Epigenomics

The team also tested whether other metabolites in cocoa and coffee showed a similar link. However, they found that the effect seemed to be specific to theobromine.

The researchers used two tests to assess the biological age of people in the study. One looked at chemical changes in DNA to estimate how quickly someone is ageing. Another estimated the length of telomeres, the protective caps on the ends of your chromosomes. Shorter telomeres are associated with ageing and age-related diseases.

Plant compounds in our diet may affect how our bodies age by changing the way our genes are switched on or off. Some of these compounds, called alkaloids, can interact with the cellular machinery that controls gene activity and helps shape health and longevity.

Theobromine, an alkaloid most commonly known as being poisonous to dogs, has been linked to health benefits in humans, such as a lower risk of heart disease. However, it has otherwise not been intensely investigated.

“This is a very exciting finding, and the next important questions are what is behind this association and how can we explore the interactions between dietary metabolites and our epigenome further? This approach could lead us to important discoveries towards ageing, and beyond, in common and rare diseases.”
— Dr Ramy Saad, lead researcher

The research team, including Professor Ana Rodriguez-Mateos who is a Professor of Human Nutrition at King’s College London, are exploring avenues for future work to dissect these results. One open question is whether the effect is unique to theobromine alone, or whether theobromine may interact with other compounds in dark chocolate, such as polyphenols, which are known to have beneficial effects on human health.

“This study identifies another molecular mechanism through which naturally occurring compounds in cocoa may support health. While more research is needed, the findings from this study highlight the value of population-level analyses in aging and genetics.”
— Dr Ricardo Costeira, Postdoctoral Research Associate

However, despite these promising findings the researchers are keen to stress that eating more dark chocolate isn’t automatically beneficial as it also contains sugar, fat and other compounds, and further research is needed to understand this association in more detail.