Gut microbiome alterations in Alzheimer’s disease Original paper
Researched by:
-
Dr. Umar
ID
Dr. Umar
Read MoreClinical Pharmacist and Clinical Pharmacy Master’s candidate focused on antibiotic stewardship, AI-driven pharmacy practice, and research that strengthens safe and effective medication use. Experience spans digital health research with Bloomsbury Health (London), pharmacovigilance in patient support programs, and behavioral approaches to mental health care. Published work includes studies on antibiotic use and awareness, AI applications in medicine, postpartum depression management, and patient safety reporting. Developer of an AI-based clinical decision support system designed to enhance antimicrobial stewardship and optimize therapeutic outcomes.
-
Dr. Umar
Read More
Researched by:
-
Dr. Umar
ID
Dr. Umar
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
Location
United States of America
Sample Site
Feces
Species
Homo sapiens
What was studied?
This original research article investigated gut microbiome alterations in Alzheimer’s disease. Using 16S rRNA gene sequencing, the authors compared fecal bacterial community composition between individuals clinically diagnosed with dementia due to Alzheimer’s disease and age- and sex-matched cognitively healthy controls. The study also explored how differentially abundant gut microbial genera correlated with cerebrospinal fluid biomarkers of amyloid and tau pathology.
Who was studied?
The study evaluated 50 community-dwelling adults: 25 with clinically diagnosed Alzheimer’s disease and 25 matched controls. Groups were comparable in age, sex, ethnicity, BMI, diabetes status, diet quality, and stool form. AD participants had very mild to moderate dementia, and most were prescribed standard AD medications. A subset of 40 participants contributed cerebrospinal fluid samples for biomarker analyses.
Most important findings
The gut microbiome of Alzheimer’s disease participants exhibited reduced richness and alpha diversity, with significant alterations in overall community structure. Firmicutes and Actinobacteria were decreased, while Bacteroidetes were increased. Genera contributing to the AD-associated signature included decreased Bifidobacterium, Adlercreutzia, Dialister, SMB53, Turicibacter, Clostridium, and cc115, alongside increased Bacteroides, Blautia, Alistipes, Phascolarctobacterium, Gemella, and Bilophila. Some of these genera showed strong correlations with AD pathology. Increased abundance of Bacteroides and Blautia was associated with lower CSF Aβ42/Aβ40 and higher p-tau and p-tau/Aβ42, reflecting greater amyloid and tau burden. Genera reduced in AD, such as SMB53 and Dialister, showed the opposite pattern, associating with less pathological biomarker profiles. These microbial shifts align with known inflammatory and metabolic characteristics of AD, including increased gram-negative bacterial signatures and reduced taxa linked to intestinal barrier integrity.
Key implications
The findings suggest a reproducible microbial signature associated with Alzheimer’s disease, marked by decreased beneficial taxa such as Bifidobacterium and increased pro-inflammatory gram-negative genera such as Bacteroides. The relationships between microbiome composition and CSF biomarkers highlight the relevance of gut–brain interactions in AD pathophysiology. This signature may inform future diagnostic or risk-stratification tools, particularly for microbiome-based biomarker databases. Moreover, decreased Bifidobacterium abundance parallels evidence supporting probiotic supplementation trials, suggesting therapeutic potential. The study underscores the need for longitudinal research to determine causality and evaluate whether modifying the microbiome could influence neurodegeneration.
Citation
Vogt NM, Kerby RL, Dill-McFarland KA, et al. Gut microbiome alterations in Alzheimer’s disease.Scientific Reports. 2017;7:13537. doi:10.1038/s41598-017-13601-y