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The Role of Gut Microbiome in Mild Cognitive Impairment: A Twin Study

Aliz Persely1, Marton Piroska1, Luca Zoldi1

  • 1Medical Imaging Centre, Semmelweis University, 1082 Budapest, Hungary.

Medicina (Kaunas, Lithuania)
|June 26, 2026
PubMed

Insights

Mild cognitive impairment (MCI) may be linked to lower levels of the gut bacterium Lachnospiraceae. This study examined gut microbiota in MCI-discordant identical twins, finding reduced Lachnospiraceae in affected individuals.

Area of Science:

  • Neuroscience
  • Microbiology
  • Genetics

Background:

  • Emerging research highlights the gut-brain axis, involving gut microbiota and metabolites in mild cognitive impairment (MCI) and Alzheimer's disease.
  • Monozygotic twins offer a unique model to study these relationships, minimizing genetic variability.

Purpose of the Study:

  • To investigate the gut microbiome's role in MCI using a discordant identical twin model.
  • To identify specific microbial taxa associated with MCI.

Main Methods:

  • Seven twin pairs discordant for ACE and 15 for MoCA were recruited.
  • Stool samples underwent 16S ribosomal RNA gene sequencing for microbiome analysis.
  • Differential abundance analysis was performed using ANCOM-BC and LEfSe.

Main Results:

  • No significant differences in overall gut microbial diversity (alpha or beta) were found between MCI-discordant twins.
  • A significantly lower abundance of Lachnospiraceae was consistently observed in MCI-affected twins.
  • Exploratory analysis suggested altered abundances of other genera, but results varied based on cognitive assessment tool.

Conclusions:

  • The reduction of Lachnospiraceae is the most robust finding, suggesting its potential role in MCI.
  • Further research with larger sample sizes and standardized cognitive assessments is needed to validate these exploratory findings.
  • Controlling for lifestyle factors like diet and physical activity is crucial for future studies.
Keywords:
Alzheimer’s diseasealpha diversitycognitive dysfunctiondementiadysbiosisgastrointestinal tractgut microbiomeneurodegeneration

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