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Gut Microbiota Composition and Plasma Metabolomic Profile Are Associated with Amyloid Pathology and Cognitive Performance in Patients with Mild Cognitive Impairment

Mora-Ortiz M, Cardelo MP, Porras-Pérez E, Serrán-Jiménez A, Ledesma-Escobar CA, Priego-Capote F, Conde-Gavilán C, Agüera-Morales E et al.

Nutrients, 2026

47 participants

Abstract

Background/objectives: The gut-brain axis and systemic metabolic dysregulation are increasingly implicated in Alzheimer's disease (AD) pathogenesis. This study aimed to characterize gut microbiota and plasma metabolomic profiles associated with amyloid pathology and cognitive impairment in patients with mild cognitive impairment (MCI).

Methods: A cross-sectional multi-omics baseline analysis was performed in 47 MCI patients enrolled in a randomized, double-blind, crossover dietary intervention trial (NCT05029765). Gut microbiota composition was assessed by 16S rRNA sequencing (n = 47), and plasma metabolomics by untargeted LC-MS/MS (n = 45 after exclusion of two PCA-defined metabolomic outliers). Patients were stratified according to plasma amyloid-beta 42/40 ratio (BA42/40) and ADAScog11 score, representing complementary biomarkers of amyloid burden and cognitive impairment, respectively.

Results: Higher amyloid burden and worse cognitive performance were associated with significant gut microbiota alterations, including increased alpha diversity and distinct beta diversity profiles. Differential abundance analyses consistently showed enrichment of Bacteroides-associated taxa and Akkermansia, alongside depletion of short-chain fatty acid-producing genera such as Faecalibacterium, Blautia, and Phascolarctobacterium. Plasma metabolomics identified a coherent signature associated with elevated BA42/40, characterized by accumulation of secondary bile acid sulfates and depletion…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 47 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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