• Researchers at King's College London compared levels of theobromine, a cocoa compound, with biological age markers.
• It emerged that those with higher levels of theobromine had a biological age lower than their actual age.
• The study is useful for exploring how diet can influence the epigenome.

Theobromine, a plant compound found in cacao, may have anti-ageing properties: this is the hypothesis put forward by research from King's College London, published in Aging.

Using data from more than 1,600 people across two European cohort studies, the researchers compared blood levels of theobromine with biological age markers — indicators of the body's apparent age based on its health status and functions, as opposed to years lived. Two tests were used to assess participants' biological age: one examined chemical changes in DNA to estimate the rate at which a person is ageing; another estimated the length of telomeres, the protective caps at the ends of chromosomes. Shorter telomeres are associated with ageing and age-related diseases.

According to the analyses, those with higher levels of theobromine circulating in their blood had a biological age lower than their actual age. Plant compounds in the diet can indeed influence how the body ages by modifying the way our genes are switched on or off. Some of these compounds, known as alkaloids — theobromine among them — can interact with the cellular machinery that controls gene activity, and contribute to shaping health and longevity.

Dark chocolate to stay younger for longer: a study that warrants further investigation

"Our study has identified a link between a key component of dark chocolate and the possibility of staying young for longer," said Jordana Bell, senior author of the paper and Professor of Epigenomics at King's College London. "We are not saying that people should eat more dark chocolate, but this research can help us understand how everyday diet can support a healthier and longer life." The team also investigated whether other metabolites found in cacao and coffee showed a similar association, but the positive effect on biological ageing appeared to be specific to theobromine.

Theobromine has already been linked to human health benefits, such as a lower risk of heart disease. This study now identifies another molecular mechanism through which natural compounds found in cacao may provide benefits. Ramy Saad, lead researcher at King's College London, also a researcher at University College London and a doctor in clinical genetics, stated: "This is a very exciting finding, and the next important questions are: what lies behind this association and how can we further explore the interactions between dietary metabolites and our epigenome? This approach could lead us to important discoveries about ageing, and beyond, in common and rare diseases."

One open question, for instance, is whether the beneficial effect is exclusive to theobromine alone, or whether theobromine may interact with other compounds in dark chocolate, such as polyphenols, antioxidant compounds. The researchers nonetheless stress that eating more dark chocolate is not automatically beneficial, as it also contains sugars, fats and other compounds, and further research is needed to gain a deeper understanding of this correlation.