Obesity may bring Alzheimer’s disease on earlier, research finds

‘Our results highlight the importance of decreasing weight in obese and overweight individuals’

OBESE people’s brains waste away in the same way as Alzheimer’s patients, research has shown.

It was known that obesity was a risk factor for dementia, but it is the first time scientists have seen how closely the brain damage from being severely overweight mimics that of Alzheimer’s.

Experts believe that the neurodegeneration caused by obesity may bring on Alzheimer’s earlier for those at risk of developing the condition, while losing weight may slow cognitive decline.

For the new research – published in the Journal of Alzheimer’s Disease – scientists at the Montreal Neurological Institute-hospital (The Neuro) at Mcgill University compared the brains of more than 1,300 people, including some participants of the UK Biobank.

The brains of Alzheimer’s patients were compared with people who did not have dementia who were either obese or a healthy weight.

Results showed that the outer layer of the brain – the cerebral cortex – had thinned in similar areas in people with Alzheimer’s as in those who were obese. No similar thinning or wasting away was seen in the healthy control group.

“We showed that one of the reasons why obesity is such an important risk factor for Alzheimer’s disease might be through neurodegeneration,” said Dr Filip Morys, of The Neuro. “Our results highlight the importance of decreasing weight in obese and overweight individuals in mid-life, to decrease the subsequent risk of neurodegeneration and dementia. Depending on many other factors, obesity may bring Alzheimer’s disease on earlier.”

Obesity is defined as having a body mass index (BMI) of 30 or higher, and around 26 per cent of adults in England are now considered obese, while almost 38 per cent are overweight.

But the risk of excess weight rises with age, with three quarters of 45-74s now overweight or obese, with figures expected to rise.

There are 944,000 people now living with dementia in Britain, with the majority suffering from Alzheimer’s. The number is expected to increase to more than one million by 2030, with one in three people born in the UK this year predicted to develop dementia in their lifetime.