Gut microbiota diversity linked to healthy cognitive function in middle-aged patients

Gut microbial composition was positively associated with healthy cognitive function in middle-aged adults, according to a cross-sectional study published in JAMA Network Open.

“Small-scale human studies have shown associations between microbial features and cognition or found significant improvements when comparing controls with persons who have been treated with probiotics to increase commensal microbiota,” Katie Meyer, ScD, of the Nutrition Research Institute at the University of North Carolina at Chapel Hill, and colleagues wrote. “However, few community-based studies have been conducted with large and diverse populations.”

Researchers sought to examine associations of gut microbial composition with measures of cognition by analyzing data from participants enrolled in the prospective Coronary Artery Risk Development in Young Adults (CARDIA) cohort, a diverse group of adults from four metropolitan areas in the United States. Researchers conducted a 30-year follow-up with 3,358 participants, aged 48 to 60 years, from 2015 to 2016. Data for the current study were analyzed in 2019 and 2020.

Meyer and colleagues sequenced stool DNA and measured gut microbiota via beta-diversity (between-person) derived with multivariate principal coordinates analysis; alpha-diversity (within-person), defined as richness (genera count) and the Shannon index (integrative measure of genera richness and evenness); and taxonomy (107 genera, after filtering).

At the 30-year follow-up, all participants underwent six clinic-administered cognitive tests: Montreal Cognitive Assessment (MoCA), Digit Symbol Substitution Test (DSST), Rey-Auditory Verbal Learning Test (RAVLT), Stroop, category fluency and letter fluency.

Of 597 participants with microbiome data (mean age, 55.2 years; 44.7% men; 45.2% Black), multivariable-adjusted principal coordinates analysis revealed tests for beta-diversity were statistically significant for all measures relating to cognition (principal component analysis, P=.001; MoCA, P=.001; DSST, P=.001; RAVLT, P=.001; Stroop, P=.007; category fluency, P=.001), with the exception of letter fluency (P=.07).

“The gut microbiota is potentially modifiable through health behaviors and targeted treatments,” Meyer and colleagues wrote. “Increments in evidence may lead to new opportunities to reduce cognitive decline in later age through designs of interventions, identification of biomarkers of risk stratification or modification of chronic diseases that lead to cognitive decline.”