In Australia, one in ten people over 65 have Alzheimer's, and three in ten people over 85 have the disease.
Researchers from Edith Cowan University (ECU) are working towards using gut microbes as a predictor for Alzheimer’s disease (AD), which has been recognised as a global health priority by the World Health Organisation.
In Australia, one in ten people over 65 have AD, and three in ten people over 85 have the disease. In Australia, dementia, of which AD is the most prevalent form, is the second leading cause of death for all residents, and according to provisional data, it is expected to become the leading cause of death within the next few years.
Furthermore, an estimated 29,000 people will suffer from young-onset dementia in 2024, and the number is expected to rise to over 41,000 individuals by 2054. This includes individuals in their 30s, 40s, and 50s.
A global estimate of the annual cost of AD and other forms of dementia is US$605 billion, equivalent to 1% of the global gross domestic product. It is predicted that by 2030, the costs associated with AD and dementia will more than double from US$1.3 trillion per year to $2.8 trillion dollars per year, according to the World Alzheimer Report 2023.
There is currently no effective treatment for AD.
ECU researcher Dr Binosha Fernando who is the lead researcher in this study, suggests that the gut microbiota–brain axis could offer insights into the early diagnosis and treatment of neurodegenerative disorders, including depression and AD.
"The human gut microbiota comprises bacteria, fungi, archaea, viruses, and protozoans existing in symbiotic relationships within the gastrointestinal tract. In the human intestine, there are approximately 1,000 species and 7,000 strains of bacteria. An imbalance in intestinal flora is implicated in various diseases, including AD."
Dr Fernando noted that gut dysbiosis assumes a pivotal role in the pathology of AD, offering a non-invasive diagnostic and potential treatment avenue. The intricate interplay between gut microbiota and AD pathogenesis involves abnormalities in amyloid-beta, tau phosphorylation, neuroinflammation, dysregulation of neurotransmitters, and oxidative stress.
"While various studies have identified functional bacteria linked to AD pathology and altered brain function, conclusive results remain elusive. Factors contributing to this ambiguity include a focus on genus-level associations without delving into species-level specifics and a lack of consideration for dietary changes.
"Ongoing research endeavours are dedicated to unravelling these mechanisms, promising valuable insights into the nuanced contributions of gut microbiota and dietary influences on cognition, dementia, and AD."
Dr Fernando is currently collecting faecal samples from The Western Australia Memory Study and The Australian Imaging Biomarkers and Lifestyle Study cohort to unlock this link.
Read the review paper as it was published in the MDPI Journal Nutrients.
