Growing old the sweet way (Monkey Business Images/Rex Features)

A SWEET tooth does more than pack on the pounds. It causes your skin to age prematurely, making you look older than you really are. But how much older?

A team led by Diana van Heemst at Leiden University in the Netherlands divided 569 healthy volunteers into three groups according to whether they had low, medium or high concentrations of blood glucose after a meal. They also studied 33 people with diabetes who had even higher blood glucose levels.

Sixty independent assessors were then asked to view pictures of the volunteers and rate how old each looked. The results show that high blood sugar levels made people look older, even when other factors affecting appearance were accounted for, such as actual age, smoking and a history of sunbathing.

The largest gap in perceived age was one year seven months, between the lowest glucose group and the diabetics, from an average of 59.6 years old to 61.2 years. But even among those without diabetes, there was a one-year gap between the lowest and highest glucose groups. Overall, there was a five-month hike in perceived age for every 0.18 gram increase in glucose per litre of blood (Age, DOI: 10.1007/s11357-011-9339-9).

“What’s happening in the body is written in the face.” says David Gunn of Unilever Research in Sharnbrook, UK, who co-led the project.