Obesity-related shifts in gut microbiota were linked to poorer attention across three cohorts, with metagenomic signals pointing to Proteobacteria species and microbial functions involved in tryptophan biosynthesis from anthranilic acid (AA) as negatively associated with attention. Plasma metabolomics and machine learning highlighted 3-hydroxyanthranilic acid (3-HAA) as positively associated with attention, particularly in obesity, while AA showed a negative association.
Bariatric surgery improved attention and increased microbial species tied to attentional measures. In preclinical models, diet-induced obesity and microbiota depletion lowered 3-HAA and 5-hydroxy-indole acetic acid (5-HIAA) in the prefrontal cortex (PFC); these decreases were reversed by fecal microbiota transplantation (FMT).
Global metabolomic profiling of PFC tissue from FMT recipients identified 3-HAA and the tryptophan/tyrosine pathways as prominent, especially when microbiota from high-attention donors were introduced. A second FMT showed transcriptional upregulation of tryptophan and tyrosine metabolism, with Haao and Aox4 as significantly regulated genes involved in 3-HAA and 5-HIAA degradation.
In a third FMT, human-to-mouse transmission of attentional traits accompanied modulation of serotonergic and dopaminergic pathways.
Gut (BMJ) published a clinical update in Research Highlights on 06 Mar 2026.
The item focuses on Gut microbial modulation of 3-hydroxyanthranilic acid and dopaminergic signalling influences attention in obesity.
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