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Updated: Apr 1, 2026

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Published on: June 2, 2022
Gut Microbiota Interacts With Brain Microstructure and Function
José-Manuel Fernandez-Real1, Matteo Serino1, Gerard Blasco1
1Department of Diabetes, Endocrinology and Nutrition (J.-M.F.-R., W.R.), Institut d'Investigació Biomédica de Girona, CIBER de la Fisiopatología de la Obesidad y la Nutrición (CIBERobn, CB06/03/0010) and Instituto de Salud Carlos III, Girona, 17007 Spain; Institut National de la Santé et de la Recherche Médicale (M.S., R.B.), Toulouse, France; Unité Mixte de Recherche 1048 (M.S., R.B.), Institut de Maladies Métaboliques et Cardiovasculaires, Université Paul Sabatier, F-31432 Toulouse Cedex 4, France; Girona Biomedical Research Institute, Department of Radiology-Institut de Diagnostic per la Imatge (G.B., J.P.), Hospital Universitari Dr Josep Trueta, Girona, 17007 Spain; Department of Computer Science, Applied Mathematics, and Statistics (J.D.-E.), University of Girona, Girona, 17071 Spain; Department of Psychiatry (F.F.-A.), University Hospital of Bellvitge-IDIBELL, Barcelona, CIBERobn, Instituto Salud Carlos III, Barcelona, 08908 Spain; and Nutren Group, Department of Experimental Medicine (M.P.-O.), PCiTAL-IRBLleida-Universitat de Lleida, Lleida, 25198 Spain.
Context:
Evidence from animals suggests that gut microbiota affects brain structure and function but evidence in humans is scarce.
Objective:
This study sought to evaluate potential interactions among gut microbiota composition, brain microstructure, and cognitive tests in obese and nonobese subjects.
Design, Setting, And Participants:
This was a cross-sectional study at a tertiary hospital including 20 consecutive obese and 19 nonobese subjects similar in age and sex.
Main Outcome Measures:
Gut microbiota (16S bacterial gene pyrosequencing), brain microstructure (diffusion tensor imaging of brain white and gray matter and R2* sequences in magnetic resonance imaging) and cognitive tests.
Results:
Hierarchical clustering revealed a specific gut microbiota-brain map profile for obese individuals who could be discriminated from nonobese subjects (accuracy of 0.81). Strikingly, Shannon index was linked to R2* and fractional anisotropy of the hypothalamus, caudate nucleus, and hippocampus, suggesting sparing of these brain structures with increased bacterial biodiversity. Microbiota profile also clustered with cognitive function. The relative abundance of Actinobacteria phylum was linked not only to magnetic resonance imaging diffusion tensor imaging variables in the thalamus, hypothalamus, and amygdala but also to cognitive test scores related to speed, attention, and cognitive flexibility.
Conclusions:
In sum, obesity status affects microbiota-brain microstructure and function crosstalk.
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