Obese people ‘suffer same brain degeneration as Alzheimer’s patients’

Obese people’s brains waste away in the same way as those of Alzheimer’s patients, new research has shown.

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

Experts believe 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, 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 Alzeimer’s patients were compared with people who did not have dementia who were either obese or of 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 and people 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. Around 26 per cent of adults in England are now considered obese, while nearly 38 per cent are overweight.

But the risk of excess weight rises with age, with three quarters of 45 to 74-year-olds now overweight or obese and that figure expected to rise.

There are 944,000 people 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 expected to develop dementia in their lifetime.

Previous research has shown that obese people are more likely to develop Alzheimer’s disease and have greater accumulation of the sticky amyloid plaques that hinder communication between cells. They also have more blood vessel damage in the brain.

Obesity is known to impact many areas and systems of the body, such as the heart, digestive system and respiratory system, but the new research shows it may be having a brain wasting effect as well. People with obesity also show some cognitive decline compared to people with healthy weight.

The research was published in the Journal of Alzheimer’s Disease.