Scientists at King's College London have found that theobromine, a compound found in dark chocolate, coffee, tea, guarana and yerba mate, is linked to slowing cell ageing[1][2][3][4][5]. Research on more than 1,600 participants showed that people with higher levels of theobromine in their blood had younger biological ages as measured by two different tests[2][4]. This effect was specific to theobromine; other substances from cocoa or coffee did not show a similar effect[1][3][4]. Theobromine is one of the alkaloids with mild stimulant effects, it acts on the nervous and circulatory systems, has anti-inflammatory and diuretic properties[1][7]. A portion of theobromine is also produced during the metabolism of caffeine and is retained in the body for several tens of hours[1][4]. The study did not show a causal link, but only an association with the biological profile[3][5]. Professor Jordana Bell, as lead author, stressed the need for further investigation into the mechanism of action[1][3].