A new study involving researchers from Mount Sinai and the University of Iowa has found that the balance of bacteria in the gut—known as the gut microbiome—may play a crucial role in cognitive health, especially in people who experience food insecurity.
Published in npj Aging, the study is the first of its kind to explore how limited access to nutritious food may change the way gut bacteria affect brain function and increase the risk of cognitive impairment.
Cognitive impairment (RCI), including problems with memory, focus, and decision-making, is on the rise worldwide as populations age. While scientists have already linked the gut microbiome to brain health through what’s known as the gut-brain axis, this new research takes it a step further by exploring how social factors, like food insecurity, may worsen the biological risks.
In the study, researchers analyzed data from 360 adults in the Survey of the Health of Wisconsin. They looked at gut microbiome samples using 16S rRNA sequencing, a genetic technique that identifies which bacteria are present in a stool sample.
They also assessed participants’ cognitive performance and asked about their experiences with food insecurity—defined as having limited or uncertain access to enough nutritious food.
The results were clear: participants with less diverse and more imbalanced gut microbiomes were more likely to show signs of cognitive decline. But the link was especially strong in people who reported being food insecure.
Certain groups of bacteria, or “microbial cliques,” were more strongly associated with cognitive problems depending on whether or not a person had reliable access to food.
For example, a bacterial clique containing Eisenbergiella or Eubacterium was more likely to be linked with cognitive impairment in people facing food insecurity. On the other hand, a different group of bacteria—including Ruminococcus torques, Bacteroides, and CAG-352F—was more strongly associated with cognitive decline in those who were food secure.
These findings suggest that the impact of gut microbes on brain health may depend not just on biology, but also on living conditions, particularly access to food.
Dr. Shoshannah Eggers, one of the study’s lead authors, explained why this is so important: “Food insecurity is usually seen as a social issue, but our research shows it could also be a biological one. The stress and poor nutrition linked with food insecurity may be changing the gut microbiome in ways that increase the risk of cognitive decline.”
Food insecurity is a growing issue. In 2022, over 17 million U.S. households—more than 12%—reported experiencing it at some point during the year, an increase from the previous year. Alongside known effects on overall health, this study adds new evidence that food insecurity may be tied to neurological decline through disruptions in gut health.
The researchers used machine learning to identify the microbial cliques that best predicted cognitive outcomes. What made the method especially valuable is that it wasn’t just predictive—it also showed which bacteria mattered most and why, offering a clearer path toward future therapies.
According to Dr. Vishal Midya, senior author of the study, this new understanding may reshape how we try to prevent or manage dementia and related conditions: “If food insecurity changes the way the gut microbiome impacts the brain, then improving access to nutritious food could be a powerful tool in reducing the risk of cognitive decline.”
The findings support the idea that public health strategies should be more integrated. Addressing cognitive decline in aging populations may require a combination of social and medical approaches—ensuring better food access while also exploring microbiome-based treatments.
In summary, this study reveals a critical three-way connection between gut bacteria, access to food, and brain health. As cognitive impairment becomes a bigger issue worldwide, especially among older adults, these insights highlight the urgent need to think beyond traditional risk factors. Nutrition, gut health, and social equity may all need to be part of the solution.
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The research findings can be found in npj Aging.
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