Gut Microbiota Associated With Cognitive Aging

Katie Meyer, ScD

While many believe the gut microbiota impacts cognitive aging, there is still a need for large-scale, community-wide sampling in this area.

A team, led by Katie Meyer, ScD, Nutrition Research Institute, University of North Carolina at Chapel Hill, identified the associations between gut microbiota composition with measures of cognition in an established population-based sample of middle-aged adults.

While early phase studies, including animal studies, have supported the idea that gut microbiota plays a role in cognitive functioning, there have been very few large community samples examined.

“Communication pathways between gut bacteria and neurologic have emerged as a novel area of research into potential mechanisms regulating brain health through immunologic, metabolic, and endocrine pathways,” the authors wrote. “Several studies have shown associations between gut microbial measures and neurological outcomes, including cognitive function and dementia.”

The Study

In the cross-sectional study, the investigators analyzed data from the prospective Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which took place in 4 metropolitan centers between 2015-2016. The analysis included 597 participants with a mean age of 55.2 years.

The investigators sequenced stool DNA and measured β-diversity (between-person) derived with multivariate principal coordinates analysis, α-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).

The investigators assessed cognitive status using 6 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.

They also measured a global score derived using principal components analysis, in which the first principal component explained 56% of variability.

The Association With Gut Microbiota

In the multivariable-adjusted principal coordinates analysis, the investigators found permutational multivariate analysis of variance tests for β-diversity were statistically significant for all cognition measures (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).

However, the investigators adjusted for sociodemographic variables, including age, race, sex and education, as well as health behaviors including physical activity, diet, smoking, and medication use, and clinical covariates, such as body mass index, diabetes, and hypertension.

Here, they found Barnesiella was positively associated with the first principal component (β, 0.16; 95% CI, 0.08-0.24), DSST (β, 1.18; 95% CI, 0.35-2.00), and category fluency (β, 0.59; 95% CI, 0.31-0.87).

In addition, Lachnospiraceae FCS020 group was positively associated with DSST (β, 2.67; 95% CI, 1.10-4.23), and Sutterella was negatively associated with MoCA (β, −0.27; 95% CI, −0.44 to −0.11).

“In this cross-sectional study, microbial community composition, based on β-diversity, was associated with all cognitive measures in multivariable-adjusted analysis,” the authors wrote. “These data contribute to a growing body of literature suggesting that the gut microbiota may be associated with cognitive aging, but must be replicated in larger samples and further researched to identify relevant pathways.”

The study, “Association of the Gut Microbiota With Cognitive Function in Midlife,” was published online in JAMA Network Open.