Brains of overweight or obese adults look ten years older than their lean counterparts, according to a new US study.
Our brains naturally shrink with age, but scientists in the US have found evidence to suggest obesity affects the onset and progression of brain ageing.
A team of scientists at the University of Cambridge studied data from more than 450 individuals between ages 20 and 87 and found the brains of obese individuals display differences in white matter.
White matter is the tissue that connects areas of the brain and allows for information to be communicated between regions.
Further analysis discovered that an overweight person at, age 50, had a comparable white matter volume to a lean person aged 60 years, implying a difference in brain age of 10 years.
The researchers only observed these differences from middle-age onwards, suggesting that our brains may be particularly vulnerable during this period of ageing.
"As our brains age, they naturally shrink in size, but it isn't clear why people who are overweight have a greater reduction in the amount of white matter," said lead author Dr Lisa Ronan from the Department of Psychiatry at the University of Cambridge.
She said they could only speculate on whether obesity might in some way cause these changes, or whether obesity is a consequence of brain changes.
That said senior author Professor Paul Fletcher, from the Department of Psychiatry, said it's essential to further investigate the findings, given we live in an "ageing population, with increasing levels of obesity."
Despite the clear differences in the volume of white matter between lean and overweight individuals, the researchers found no connection between being overweight or obese and an individual's cognitive abilities, as measured using a standard test similar to an IQ test.
The study has been published in the journal Neurobiology of Aging.
