In this study from Washington University, people with pre-clinical Alzheimer’s were found to have higher populations of certain bacteria involved in breaking down the amino acids arginine and ornithine, and lower levels of those involved in protecting neurons. These changes in gut bacteria were present years before people developed cognitive issues like memory loss and confusion and reinforce previous studies that demonstrated a link between the composition of gut bacteria and the amount of amyloid – a marker for Alzheimer’s – in the brain.
The lead author of the study speculates that certain species of bacteria cause inflammation in the gut, which then leads to a widespread inflammatory response that affects the brain via the gut-brain axis. When combined with other risk factors like family history, age, brain imaging and genetics, information about the gut microbiome may improve our ability to predict who is at highest risk of developing Alzheimer’s – and provide opportunities to intervene earlier before neurodegenerative changes set in.
