Gut microbiome composition and food insecurity linked to risk of cognitive impairment in adults

A study led in part by Mount Sinai researchers has found a compelling link between the composition of the gut microbiome and the risk of cognitive impairment (RCI) in adults, underscoring the complex role that both biology and social determinants—such as food insecurity—play in brain health.

This is the first epidemiologic study to assess the modifying role that food insecurity may play in the relationship between the gut microbiome and RCI.

Published in npj Aging, this study investigated the role of food insecurity as an effect modifier between specific groups of microbes in the gut microbiome and RCI.

The research shows that adults with lower microbial diversity and specific imbalances in gut bacteria were significantly more likely to experience cognitive impairment. The analysis also found that food insecurity—limited or uncertain access to adequate food—was independently associated with both poorer gut health and diminished cognitive performance.

“More than 12% (17.0 million) of U.S. households in 2022 experienced food insecurity at some point throughout the year, showing an increase from the 10.2% (13.5 million) prevalence in 2021,” said Shoshannah Eggers, Assistant Professor, Epidemiology, University of Iowa College of Public Health, and corresponding author on this study. Dr. Eggers began working on this study while a Postdoctoral Fellow at the Icahn School of Medicine at Mount Sinai.

“Food insecurity is consistently linked to adverse health outcomes such as poorer overall health and adverse neurological health outcomes. Understanding how gut health and social conditions interact gives us a fuller picture of what puts people at risk for cognitive decline,” said Dr. Eggers, who also serves as co-director of the Microbial Exposomics Lab and an associate member of the Environmental Health Sciences Research Center at the University of Iowa College of Public Health.

The study included 360 adult participants from the Survey of the Health of Wisconsin with complete data on food insecurity, RCI, and 16S rRNA sequencing—a test to figure out which bacteria are present in a stool sample.

Small groups of closely connected microbes (known as microbial cliques) associated with RCI were identified using an interpretable machine-learning-based algorithm—a type of machine learning model that not only makes predictions or decisions but also lets researchers understand how and why it made those predictions. All analyses were stratified by food insecurity level and adjusted for relevant confounders, like age, body mass index, and smoking.

The researchers identified two cliques whose associations with RCI were modified by food insecurity status. The presence of the clique with either Eisenbergiella or Eubacterium was more strongly associated with RCI for the food-insecure group. A clique representing the presence of Ruminococcus torques, Bacteroides, CAG-352F, and/or Eubacterium had a stronger association with RCI for the food-secure group.

The contrasting results between food-secure and food-insecure groups may be particularly important while devising microbial interventions for cognitive impairment, as food security status may alter the effectiveness of such interventions.

“These findings suggest that food insecurity is not just a socioeconomic issue—it may be a biological one too, influencing brain health via changes to the gut microbiome,” said Vishal Midya, Ph.D., MStat, Assistant Professor of Environmental Medicine at the Icahn School of Medicine at Mount Sinai and senior author of the study.

“Cognitive impairment, including mild cognitive impairment and dementia, is increasing, particularly among older adults, and is primarily driven by an aging population. Future studies investigating why cognitive problems develop in people should consider food insecurity as one possible contributing factor.”

The study calls for more integrated public health approaches that address both nutritional access and gut health. It also opens the door for future interventions combining dietary support and microbiome-targeted therapies to reduce the risk of dementia, particularly in vulnerable populations.