A team of Australian researchers has discovered a potential blood biomarker that can signal the risk of dementia much earlier and help people to make lifestyle changes to help ward off the disease.
Researchers from Macquarie University and the CSIRO, Australia's national science agency found that people with increased levels of 3-HAA can raise the risk of Alzheimer's by 35 times.
The team looked at samples from 239 people with an average age of 75. Of these, 166 went on to develop Alzheimer's.
The samples were taken every 18 months as part of a long-term study of healthy older Australians.
"We found that someone with increased levels of 3-HAA is 35 times more likely to progress to Alzheimer's than someone with normal levels," said David Lovejoy from Macquarie Medical School.
This is the first time higher 3-HAA levels have been shown to be an early warning sign of the disease. In the past, 3-HAA has been observed to actually decrease after a diagnosis of dementia, but nobody has ever looked back to measure it in the lead-up.
So, the team were surprised to see increased 3-HAA levels strongly predicting risk of developing mild cognitive impairment that leads to a diagnosis of dementia.
"Increased levels of the 3-HAA metabolite have been shown to impair the immunological response to the build-up of amyloid in the brain, one of the key 'bad-actors' in the development of Alzheimer's," Lovejoy added.
While at this early stage, the process of testing for 3-HAA is at laboratory stage, there is every reason to believe that it will be possible to develop a rapid blood test in the future, the team said.
"In theory, if you found your levels were high, you would get a brain scan to determine whether there was also a build-up of amyloid plaques, which is an indicator of Alzheimer's, and begin taking preventative measures," Lovejoy said.
"We don't know yet whether increased levels of 3-HAA leading up to dementia can be reversed. That is something that needs more research, but there are so many exciting possibilities here.
"There would also be the potential to use such a test to check whether new Alzheimer's therapies were working. In theory if levels of 3-HAA began to fall, it might indicate that the treatment was having the desired effect," Lovejoy said.
Fortunately, Lovejoy noted there are lifestyle changes anybody can make at any age that help reduce chronic inflammation including a proper nutritious diet that is low in red meat and processed foods and rich in vegetables, such as leafy greens and red berries; and at least 30 minutes of exercise every day, such as walking, swimming or cycling; and reducing alcohol consumption.