Impacts of an antioxidant-rich diet and lifestyle factors on gut microbiota diversity and brain health: An exploratory analysis from the NutBrain study.

Higher total dietary antioxidant capacity (ORAC) was significantly associated with greater gut microbiota alpha-diversity.

• Association was statistically significant at p ≤ 0.05
• Gut microbiota diversity was assessed using 16S rRNA amplicon-based sequencing of stool samples
• The study included 246 dementia-free individuals aged ≥65 years from the NutBrain study (2019–2023)
• ORAC was estimated from 3-day food diaries and analyzed in tertiles

Several gut microbial taxa showed increased abundances in the highest ORAC and healthy lifestyle score (Hscore) tertiles compared to the lowest tertiles.

• Taxa with increased abundances included Barnesiella, Coprococcus, Ruminococcus, Parabacteroides, Lachnospiraceae NK4A136 group, and Clostridia UCG-014 group
• Comparisons were made between the highest and lowest tertiles of both ORAC and Hscore
• The Hscore combined dietary antioxidant capacity (ORAC) with smoking status and physical activity

The highest tertile of total ORAC was positively and significantly associated with greater total brain, white matter, and grey matter volumes.

• Associations were statistically significant at p ≤ 0.05
• Brain morphometry was assessed using magnetic resonance imaging (MRI)
• Brain volumes measured included total brain, white matter, grey matter, and ventricular cerebrospinal fluid volumes
• Multiple linear regression models accounted for socio-demographics, drug use, energy intake, inflammatory and anthropometric markers, and APOE genotyping

Associations between antioxidant-rich diet and brain/microbiota outcomes were stronger in participants with a favorable lifestyle profile.

• Favorable lifestyle was defined as regular physical activity and non-smoking status
• Notable correlations were observed for total brain volume, gut alpha-diversity, white matter volume, and MMSE scores (p ≤ 0.05)
• A composite healthy lifestyle score (Hscore) was devised combining ORAC with smoking and physical activity
• These stronger associations were identified in subgroup analyses of participants classified with a favorable lifestyle profile

The study population consisted of 246 dementia-free older adults assessed cross-sectionally as part of the NutBrain cohort.

• Participants were aged ≥65 years
• The study was conducted between 2019 and 2023
• Global cognitive function was assessed using the Mini-Mental State Examination (MMSE)
• The study was registered as NCT04461951
• Cross-sectional design limits causal inference

An antioxidant-rich diet was associated with better cognitive function as measured by MMSE scores.

• MMSE was used to assess global cognitive function
• The association with MMSE was noted particularly in individuals with a favorable lifestyle profile (p ≤ 0.05)
• Analyses controlled for numerous confounders including APOE genotyping, inflammatory markers, and socio-demographics