Can your gut microbiota predict the risk of developing Alzheimer's? A pioneering study out of Spain is opening up a new avenue for the early detection of this neurodegenerative disease.
The research suggests that certain patterns in the gut microbiota could act as early biomarkers of the genetic risk associated with Alzheimer's, even in young, healthy people.
We caught up with Dr Carlo Bressa, a professor and academic researcher at the Universidad Francisco de Vitoria’s (UFV) Institute of Biomedical Research, who is lead co-author of the study. He explained how these findings could transform how we approach personalised Alzheimer's prevention.
From the potential of non-invasive diagnostics to the crucial role the gut health plays in brain function, we delve into research that could change how we understand and tackle a disease currently affecting more than 50 million people worldwide.
© Getty ImagesHow did the idea of looking into the connection between gut bacteria and the genetic risk of Alzheimer's come about?
"The research stems from growing evidence linking our gut bacteria to brain health, particularly via the gut-brain axis. There are clear signs that the microorganisms living in our gut can influence the inflammatory and metabolic processes that affect the development of neurodegenerative conditions like Alzheimer's.
"While APOE4 is widely recognised as the primary genetic risk factor for the disease, the way our genetics, metabolism and microbiota interact seems to influence the underlying biological mechanisms that trigger it. Because of this, we wanted to see if carrying the APOE4 gene caused noticeable differences in gut bacteria even in healthy adults, long before any neurological symptoms or related illnesses appear."
"This kind of research paves the way for the precision medicine of the future - specifically, highly personalised preventive care"
Why is the APOE4 gene so significant when it comes to studying Alzheimer’s?
"It is the single biggest genetic risk factor we know of for Alzheimer's, significantly increasing the likelihood of developing the condition, and often at a much younger age. APOE4 disrupts processes that are absolutely vital to brain health—such as fat metabolism, inflammation and how the brain handles oxidative stress. It is also involved in how brain cells repair and adapt. Because of this, it is crucial to investigate how APOE4 interacts with other environmental and biological factors, such as our gut bacteria, to fully grasp its impact on brain health."
Could the changes in gut bacteria you've identified eventually be used as reliable warning signs for an early diagnosis?
"As things stand, the shifts we've spotted in the microbiota simply give us a picture of a person's risk profile—they aren't yet robust enough to be used as early diagnostic tools on par with the APOE4 gene itself. Before we can use them in a clinical setting, we need larger-scale studies to confirm that these patterns show up consistently across different groups of people, that they remain stable despite everyday lifestyle changes and that they genuinely track alongside cognitive decline over time."
What possibilities does this study open up for the personalised prevention of Alzheimer’s?
"This kind of research lays the groundwork for the precision medicine of the future—specifically, personalised prevention strategies where genetic risk could be managed by looking after our individual gut health. If these metabolic and functional links are confirmed, targeted microbiome care could become a brilliant complementary pathway to help delay the onset of symptoms in people carrying the APOE4 gene."
© GettyWhat kind of treatments or lifestyle changes could be introduced for people with a genetic predisposition?
"The possibilities range from simple dietary changes—such as tweaking macronutrients or increasing fibre—to the targeted use of prebiotics, probiotics or synbiotics. The goal would be to boost the beneficial bacteria or microbial functions that tend to be lacking in APOE4 carriers. On top of that, everyday healthy habits like staying active, quitting smoking and getting enough sleep can dramatically improve microbial balance and contribute to long-term brain health."
What are the main hurdles in translating these findings into actual clinical practice?
"There are several challenges. First, there is the sheer variation in gut bacteria from person to person, alongside the massive influence of everyday factors like diet, medication and even where we live. We also currently lack validated biomarkers and, crucially, we need to back up these findings with long-term, diverse and multi-centre studies. On top of all that, it is incredibly difficult to design treatments that are both safe and effective enough to genuinely lower a patient's long-term risk."
"Maintaining a balanced, varied, and fibre-rich diet, along with regular moderate exercise and stress management, does far more than just promote digestive wellbeing; it directly supports the gut-brain connection"
Do you think we will soon be able to use gut analysis as a routine tool to detect diseases like Alzheimer's early?
"Right now, using these tests as a routine diagnostic tool is still premature. However, with rapid technological advances and the sheer volume of data being gathered, we might only be a few years away from integrating a person's microbial profile as a helpful extra factor when assessing their risk and planning preventive care—always, of course, alongside other clinical and biological markers."
What is your main message to the public about looking after their gut health to protect their brain?
"Our gut and brain health are deeply connected. Maintaining a balanced, varied and fibre-rich diet, along with regular moderate exercise and stress management, does far more than just promote digestive wellbeing—it also helps maintain the vital inflammatory and metabolic balance that protects our brain function as we get older."
