Frail older people are at greater risk of getting dementia, even when their brains are relatively healthy. Becoming frail in later life may make people more vulnerable to even the slightest brain changes that cause Alzheimer’s disease.A study of more than 450 older people found the most frail were most in danger of the memory-robbing disease. Those with low levels of the proteins which build up in the brain and cause dementia are the lucky ones who should be spared from the disease.But just over one in ten people in the study were diagnosed with dementia despite having a relatively healthy brain. The answer to why people with apparently healthy brains get dementia appears to be their physical health.More than two-thirds of people with fairly healthy brains who got dementia were highly frail, compared to just five per cent of very fit pensioners. Experts now believe frailty could reduce people’s tolerance to brain changes, so that they are more likely to become forgetful.It could see older people advised to exercise more and change their diet to make them stronger. Professor Kenneth Rockwood, who led the study from Dalhousie University in Canada, said: ‘People with more frail bodies are more likely to have frail brains, which make it harder to resist the proteins that we know cause Alzheimer’s disease.‘This explains why frail people could develop dementia when less frail people with exactly the same build-up of proteins in their brains may have far fewer symptoms and never be diagnosed with dementia at all.’Scientists have puzzled for decades over why people with little sign of dementia in their brains are diagnosed with it anyway.To determine the importance of frailty, researchers monitored older people’s self-reported health, walking speed, grip strength and balance.People’s ability to do simple daily activities like dressing themselves, shopping and preparing meals were assessed.Published in Daily Times, January 21st 2019.