While many believe the gut microbiota impacts cognitive aging, large-scale, community-wide sampling is still needed in this area.
A team, led by Katie Meyer, ScD, Nutrition Research Institute, University of North Carolina at Chapel Hill, identified associations between gut microbiota composition and measures of cognition in an established sample of middle-aged adults based on population.
While early phase studies, including animal studies, have supported the idea that the gut microbiota plays a role in cognitive functioning, very few large community samples have been examined.
“Communication pathways between gut bacteria and neurologicals have emerged as a new area of research into potential mechanisms regulating brain health through immunological, metabolic, and endocrine pathways,” the authors wrote. “Several studies have shown associations between gut microbial measures and neurological outcomes, including cognitive function and dementia.”
In the cross-sectional study, researchers analyzed data from the prospective Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which took place in 4 metropolitan centers between 2015 and 2016. The analysis included 597 participants with a mean age of 55.2 years.
Investigators sequenced stool DNA and measured β (inter-person) diversity derived from a multivariate analysis of principal coordinates, α (within-person) diversity, defined as richness (number of genera) and Shannon’s index (integrative measure of the richness and regularity of genres). ), and taxonomy (107 genera, after filtering).
Investigators assessed cognitive status using 6 clinic-administered cognitive tests: Montreal Cognitive Assessment (MoCA), Numerical Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), Stroop, Category Fluency and Letter Fluency.
They also measured an overall score derived from principal component analysis, in which the first principal component explained 56% of the variability.
The association with the intestinal microbiota
In multivariate adjusted principal coordinate analysis, the researchers found that permutational multivariate analysis of variance tests for β-diversity were statistically significant for all cognitive measures (principal component analysis, P = 0.001; MoCA, P = 0.001; DSST, P = 0.001; RAVLT, P= 0.001; Stroop, P= 0.007; mastery of the category, P= .001) with the exception of the mastery of letters (P= 0.07).
However, the investigators adjusted for sociodemographic variables, including age, race, gender, and education, as well as health-related behaviors, including physical activity, diet, smoking, and substance use. medications, and clinical covariates, such as body mass index, diabetes, and hypertension.
Here they found Barnesiellawas positively associated with 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, Group Lachnospiraceae FCS020was positively associated with DSST (β, 2.67; 95% CI, 1.10-4.23), and Sutterellawas 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 a multivariate adjusted analysis,” the authors wrote. “These data contribute to a growing number of publications suggesting that the gut microbiota may be associated with cognitive aging, but needs to be replicated in larger samples and further investigated to identify relevant pathways.”
The study, “Association of the Gut Microbiota With Cognitive Function in Midlife,” was published online in Open JAMA Network.