How a sweet tooth leads to senior moments

Raised blood sugar levels may be to blame for memory lapses that commonly occur with increasing age, according to a study by Columbia University Medical Centre in New York.

The research suggests that, even in healthy individuals with no hint of diabetes, keeping blood sugar under control could be the key to preventing so-called "senior moments". Taking regular physical exercise and eating the right foods are two strategies that may help achieve this, say the scientists. If necessary, blood sugar levels can be lowered with drugs.

Some degree of mental decline, marked by episodes of forgetfulness, is a part of normal ageing and does not always herald the onset of Alzheimer's disease or other forms of dementia. Both the problems of normal ageing and Alzheimer's involve the hippocampus, the centre of memory and learning in the brain.

Earlier research led by Dr Scott Small, from Columbia University Medical Centre, showed that one area of the hippocampus called the dentate gyrus is mainly responsible for normal age-related memory decline. In the new study, published in the journal Annals Of Neurology, his team conducted brain scans of human volunteers and animals to find out what was affecting the dentate gyrus. The scientists discovered that reduced activity in this part of the brain was closely correlated with higher levels of blood sugar.

Dr Small said: "Showing for the first time that blood glucose selectively targets the dentate gyrus is not only our most conclusive finding, but it is the most important for 'normal' ageing – that is, hippocampal dysfunction that occurs in the absence of any disease states. There have been many proposed reasons for age-related hippocampal decline. This new study suggests that we may now know one of them.

"Whether with physical exercise, diet or through the development of potential pharmacological interventions, our research suggests that improving glucose metabolism could be a clinically viable approach for improving the cognitive slide that occurs in many of us as we age."