Food desert residence has limited impact on veteran fecal microbiome composition: a U.S. Veteran Microbiome Project study.

Social and economic inequities can have a profound impact on human health, particularly on the development and progression of chronic disease. For military veterans, exposure to unique environments and circumstances may further impact their health. There continues to be limited work regarding the influence of mental health within the context of socioeconomic inequities. In this cross-sectional study, we hypothesized that veterans residing in food deserts (e.g., places in which there is a lack of access to sufficient and/or nutritious food) would have decreased gut microbial species (α-diversity), different microbiome community compositions, and poorer quality of diet and mental health compared to non-food desert residents. The fecal microbiome of 342 military veterans was sequenced, and microbiome diversity and community composition were evaluated. Although dietary quality and α-diversity did not significantly differ by food desert status, resident status (food desert versus non-food desert) accounted for a moderate influence on β-diversity (2.4%). Factors such as race and psychiatric diagnoses accounted for greater proportions of β-diversity influence (7% and 10%, respectively). Moreover, more participants with current post-traumatic stress disorder lived in food deserts ( P < 0.04), and there were significantly more participants in the non-food desert group diagnosed with substance use disorders ( P = 0.002) and current alcohol use disorder ( P = 0.04). These findings suggest that living in a food desert, in combination with additional associated risk factors, may influence gut microbial diversity and composition. To increase ecological validity, researchers investigating the influence of inter-related biopsychosocial factors over time may benefit from adopting a life-course perspective.IMPORTANCESocial and economic inequities can have a profound impact on human health. The inequities could result in alterations to the gut microbiome, an important factor that may have profound abilities to alter health outcomes. Moreover, the strong correlations between social and economic inequities have been long understood. However, to date, limited research regarding the microbiome and mental health within the context of socioeconomic inequities exists. One particular inequity that may influence both mental health and the gut microbiome is living in a food desert. Persons living in food deserts may lack access to sufficient and/or nutritious food and often experience other inequities, such as increased exposure to air pollution and poor access to healthcare. Together, these factors may confer a unique risk for microbial perturbation. Indeed, external factors beyond a food desert might compound over time to have a lasting effect on an individual's gut microbiome. Therefore, adoption of a life-course approach is expected to increase the ecological validity of research related to social inequities, the gut microbiome, and physical and mental health.