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Mediterranean diet, gut microbiota, and cognitive decline in older adults with obesity/overweight and metabolic syndrome: a prospective cohort study

Jia-Qi Ni, Adrián Hernández-Cacho, S. K. Nishi, N. Babio, Clara Belzer, Prokopis Konstati, J. Vioque, D. Corella et al.

BMC Medicine, 2025

746 participants · 18 citations

Abstract

Emerging evidence highlights that diet dynamically shapes the gut microbiome, which in turn influences cognitive function through bidirectional gut-brain communication, offering a promising target for mitigating cognitive decline and neurodegenerative disorders. While the Mediterranean diet (MedDiet) is a well-established dietary pattern with demonstrated neuroprotective benefits, the interplay between MedDiet adherence, gut microbiota, and longitudinal cognitive trajectories remains poorly understood. We aimed to identify a gut microbial signature of the MedDiet adherence and prospectively examine the associations of MedDiet adherence and MedDiet gut microbial signature (MedDiet-GMS) with cognitive changes over time in older adults at high risk of cognitive decline. This study included 746 participants (mean age 65 ± 5 years, 48% women) with overweight/obesity and metabolic syndrome. Adherence to the MedDiet was assessed using a validated 14-item Mediterranean Diet Adherence Screener (MEDAS). Baseline gut microbiota composition was profiled via 16S rRNA sequencing. Cognitive function was evaluated at baseline, 2, 4, and 6 years using a comprehensive neuropsychological battery. Elastic net regressions were applied to derive a MedDiet-GMS, and linear mixed models were used to assess associations of both MEDAS and MedDiet-GMS with trajectories of cognitive function, adjusting for potential confounders. Higher adherence to the MedDiet was associated with greater gut microbial…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 746 participants or records.

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