Socioeconomic status and population density influence our gut microbiome, according to recent studies.

In one report published by Ars Technica on March 14 2024, urban humans have lost their ability to digest plants, specifically cellulose which line the walls of plants (1). While humans are host to a mix of cellulose-eating bacteria, urban living has caused the number of these bacteria to shrink dramatically, possibly down to one species. Present-day hunter/gatherers and those living in a rural environment, both of whom eat very high fiber diets, still had about 20 percent prevalence of these cellulose-digesting species. By contrast, those in industrialized countries had a prevalence under 5 percent.

For example, according to a March 15 2024 Science report, researchers found numerous rumicococcus strains, Candidatus Ruminococcus primaciens, Ruminococcus hominiciens, and Ruminococcus ruminiciens, all of which help digest cellulose. These species are found prevalent in great apes and primates, and today’s rural populations, but not in industrialized urban populations (2).

On the flip side, researchers found a number of factors of socioeconomic status (SES). A March 11 2024 the Food and Microbiome Longitudinal Investigation (FAMiLI) study, published in Nature of 825 participants determined the relationship of a range of individual- and neighborhood-level SES indicators with the gut microbiome. Lower socioeconomic status (SES) is related to increased incidence and mortality due to chronic diseases, but this study suggests biological factors that influence SES (3).

Certain gut bacteria were found prevalent among low SES, others among high SES participants. For example , low SES individuals showed a higher abundance of Prevotella and a lower abundance of Bacteroides. 

These are broad generalizations, but the study found that Hispanic and Black participants were more likely in poor neighborhoods to have lower SES, including lower education, occupation, neighborhood income, and deprivation. United States-born participants had higher SES as compared to foreign-born participants, according to New Medical (4).

1) https://arstechnica.com/science/2024/03/human-gut-bacteria-that-can-digest-plant-matter-probably-came-from-cows/

2) https://www.science.org/doi/10.1126/science.adj9223

3) https://www.nature.com/articles/s41522-024-00491-y

4) https://www.news-medical.net/news/20240314/Socioeconomic-status-shapes-the-gut-microbiome-in-diverse-US-population.aspx