December 16, 2025
Deb Cram/Seacoastonline and Fosters.com; USA TODAY NETWORK
New research adds to a growing body of evidence showing the health benefits of dark chocolate, but eating it in moderation is key, health experts say.
Eating modest amounts of dark chocolate may help slow the aging process, new research suggests.
People with higher levels of theobromine in their blood were found to have biological ages lower than their chronological ages in a study conducted by researchers at King's College London in the United Kingdom. Theobromine is a compound in cocoa, the main ingredient in dark chocolate.
Biological age has to do with how old the body's cells are, as opposed to chronological age, the number of years someone has been alive. For some people, their biological age is different from their chronological age, and scientists are still unraveling how to measure biological age, according to Northwestern Medicine.
"Our study finds links between a key component of dark chocolate and staying younger for longer," said Jordana Bell, the study's senior author and a professor in epigenomics at King's College London. "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."
Previous research has shown several benefits of eating moderate amounts of dark chocolate high in cocoa content, including antioxidant effects and improved heart health. Dark chocolate also may lower cholesterol and blood pressure. Another study even found that eating a small amount of dark chocolate each day may reduce the risk of type 2 diabetes.
The authors of the new study, published Wednesday in the journal Aging, said more research is needed to determine if theobromine alone may be responsible for slowing the aging process or whether the benefits come from its interaction with other compounds in dark chocolate. They also warned that eating dark chocolate may not necessarily make people healthier, because it also contains sugar and fat.
Dark chocolate's health benefits stem from its cocoa content, which ranges from 50% to 90%, compared to the 10% to 50% found in milk chocolate, Harvard Health says.
Nutritionists generally recommend choosing dark chocolate with cocoa contents of 70% or higher, according to EatingWell, which offers advice on the best dark chocolate bars.
