Being overweight in middle-age makes the brain age by 10 years, research by the University of Cambridge has found.

The study, which scanned 473 brains, found changes in the brain structure of overweight people which are normally seen in those far older.

The volume of white matter - the tissue that connects areas of the brain and allows information to be communicated between regions - shrunk far more in those with a Body Mass Index above 25.

Shrinkage of parts of the brain is associated with a higher risk of cognitive decline and dementia.