Food Insecurity Modifies the Association Between the Gut Microbiome and the Risk of Cognitive Impairment in Adults

Background: Recent studies have shown associations between relative abundances of specific gut microbes and cognitive function; however, few studies have explored the potential interplay between the gut microbiome and food insecurity in association with the risk of cognitive impairment (RCI). This study investigated the role of food insecurity as an effect modifier between the gut microbiome, including groups of gut microbes (microbial cliques), and RCI.

Methods: Data came from the Survey of the Health of Wisconsin and its ancillary Wisconsin Microbiome Study. The analytical sample (n = 360) included adult participants with complete data on food insecurity, RCI, and 16S rRNA sequencing data from stool samples. A "mini-cog" memory test was implemented to assess RCI. Food insecurity was assessed using a set of survey-based questions. Alpha diversity and individual taxa associations with RCI were estimated using linear regression. Microbial cliques associated with RCI were identified using an interpretable machine-learning-based algorithm. All analyses were stratified by food insecurity level, and regression models were adjusted for relevant confounders.

Results: Food insecurity status was weakly associated with RCI (b = 0.06, 95%CI=[0.00, 0.12]). Gut microbiome a-diversity had an inverse association with RCI in both the food secure (b=-0.08, 95%CI=[-0.15, -0.02]) and insecure groups (b=-0.09, 95%CI=[-0.26, 0.07]). Bacteroides sp. was associated with RCI in the food secure group only (b = 0.09, 95%CI= [0.05, 1.36]. We identified two microbial cliques whose associations with RCI were modified by food insecurity status. The presence of the microbial clique with either Eisenbergiella or Eubacterium was more strongly associated with RCI for the food-insecure group (β = 0.29, p < 0.0001) than the food-secure group (β = 0.05, p < 0.001). Alternatively, a microbial clique representing the presence of Ruminococcus torques, Bacteroides, CAG-352F, and/or Eubacterium had a stronger association with RCI for the food-secure group (β = 0.1, p < 0.0001) than the food-insecure group (β = 0.07, p = 0.01).

Conclusions: Food insecurity may modify the relationship between the gut microbiome and RCI. These findings suggest environmental and lifestyle factors in potential prevention strategies against RCI.