A retrospective study on blood microbiota as a marker for cognitive decline: implications for detecting Alzheimer’s disease and amnestic mild cognitive impairment in Republic of Korea

Distinct bacterial taxa-particularly the increase in Gammaproteobacteria along with decreases in Bacteroidia, Alphaproteobacteria, and Clostridia-are associated with the progression of cognitive decline. These findings suggest that blood microbiota could serve as potential biomarkers for the early detection of aMCI. However, the small sample size and the lack of control for confounding factors such as diet and medication limit the findings. Larger studies are needed to validate these results and further explore the role of microbiota in neurodegeneration.