New blood test uses gut health to help predict cognitive decline years earlier

Researchers have found dementia markers in a gut microbiome-focused blood test. Hinterhaus Productions/Getty Images This article originally appeared on Medical News Today Diagnosing dementia at its earliest stages is important for granting people earlier access to treatments.

Over the last few years, researchers have been focused on finding new ways, such as blood tests, to help doctors diagnose dementia as early as possible. Researchers of a new study have developed the basis for a new blood test for the early diagnosis of dementia based on changes occurring in their gut microbiome.

Over the last few years, researchers have been focused on finding new ways to help doctors diagnose dementia as early as possible. Diagnosing dementia at its earliest stages can help ensure people get access to treatments earlier, which can help with symptom management and quality of life.

Some of these methods for diagnosing dementia at its earliest stages are blood tests searching for specific biomarkers that can be signs of dementia. Now, researchers from the University of East Anglia in the United Kingdom have developed the basis for a new blood test for the early diagnosis of dementia based on changes occurring in their gut microbiome .

Their research was recently published in the journal Gut Microbes . Metabolites help classify MCI vs.

healthy brain For this study, researchers analyzed blood and stool samples from 150 adults ages 50 and over. Recruited study participants ranged from no signs of cognitive impairment, to those with mild cognitive impairment (MCI) — which can be an early sign of dementia — and participants with subjective cognitive impairment (SCI) , which is a self-reported decline in cognitive abilities like memory.

Through the blood and stool samples, scientists identified 33 key molecules produced by the gut microbiome and diet, as well as the bacteria living in their gut, called microbe-derived metabolites . Using AI-powered machine learning, researchers examined different combinations of these chemicals to see how different combinations could help them identify healthy participants from those with MCI or SCI.

Scientists reported that even in study participants who had only started to notice mild memory changes, there were clear modifications to their gut bacteria and the metabolites they release into the bloodstream. Using just six of the discovered metabolites, the AI model was able to classify participants into the study’s three defined participant groups with 79% accuracy, and could tell healthy adults from those with MCI with more than 80% accuracy.

“This adds weight to growing evidence that the so‑called gut–brain axis — the communication network between our digestive system and the brain — may play an important role in cognitive aging,” David Vauzour, PhD , associate professor in molecular nutrition in Norwich Medical School at the University of East Anglia, and lead author of this study, says in a press release . “If particular gut bacteria or the chemicals they produce contribute to early cognitive decline, treatments involving diet, probiotics , microbiome‑based therapies, or personalized nutrition could one day form part of dementia prevention strategies.” — David Vauzour, PhD Understanding the gut-brain link So how could what’s going on in our digestive systems impact our brain health?

“The gut and brain are connected through what is known as the microbiota-gut-brain axis,” Manisha Parulekar, M.D., FACP, AGSF, CMD , director of the Division of Geriatrics at Hackensack University Medical Center and co-director of the Center for Memory Loss and Brain Health at Hackensack University Medical Center in New Jersey, explained to Medical News Today . “The bacteria in our gut produce various compounds, or metabolites, from the food we eat.

These metabolites can enter the bloodstream and influence brain health,” she said. “Analyzing metabolites and gut microbiome changes offers a chance to spot early signs of cognitive decline, as emerging evidence shows that the gut microbiome is important for brain health through the microbiota–gut–brain axis, which involves metabolic, immune, and neural signaling pathways,” said Peter Gliebus, MD , chief of neurology and director of cognitive and behavioral neurology at Marcus Neuroscience Institute, part of Baptist Health South Florida.

“ Dysbiosis in the gut can cause neuroinflammation, blood-brain barrier issues, and neuronal damage, all linked to cognitive decline and dementia. Metabolites such as indoxyl sulfate , choline , and tryptophan -derived compounds participate in important processes such as neurotransmitter production, oxidative stress regulation, and inflammation.

Changes in their levels may indicate early disease processes before symptoms appear.” — Peter Gliebus, MD “Additionally, metabolite profiling and microbiome analysis can be performed using blood and stool samples, making these approaches less invasive and more accessible than traditional methods such as brain scans or spinal fluid tests,” Gliebus added. Research in larger, more diverse populations needed MNT also spoke with Dung Trinh, MD , internist for the MemorialCare Medical Group and chief medical officer of the Healthy Brain Clinic in Irvine, CA, about this study, who commented his first reaction was that this is a promising and biologically interesting study, but still early-stage research.

Correlation, not causation “It suggests that a small panel of blood metabolites linked to diet and the gut microbiome may help identify people with very early cognitive changes, which is exciting because we need less invasive ways to detect risk sooner. At the same time, this was a relatively small, cross-sectional study, so it shows association rather than proving that these markers can reliably predict who will go on to develop dementia.” — Dung Trinh, MD Trinh said the next step in this research is to test these findings in larger, more diverse groups of patients followed over time, so we can see whether these metabolite patterns truly predict future cognitive decline rather than simply reflecting differences already present.

“I would also want to see the results replicated across different populations and compared directly with established Alzheimer’s blood biomarkers to understand whether they add meaningful value,” he added. “Ultimately, the field should move toward intervention studies to determine whether targeting diet, metabolism, or the gut microbiome could actually help delay or prevent decline.”