Race-Based Variation in Gut Microbiome Emerges Early in Life

Megan Brooks

August 24, 2023


Social and environmental factors drive race and ethnicity-associated gut microbiome variation that arise around 3 months of age, which may contribute to adult health and health disparities, new research shows.


  • Researchers analyzed data from eight cohort studies with 2756 gut microbiome samples from 729 children of diverse race/ethnic backgrounds from birth to 12 years of age.

  • They stratified the samples by age to pinpoint when variation in the gut microbiome appears.

  • They used statistical models to identify differentially abundant bacterial species.


  • Race/ethnicity account for "small but statistically significant" proportions of the variation in the gut microbiome composition.

  • There was no significant race/ethnic variation in the gut microbiome present at birth or shortly thereafter, when vertical microbial transmission are expected to be strongest.

  • Rather, external factors likely shape race/ethnic variation in the gut microbiome that are present at or shortly after 3 months of age and persist through childhood.

  • Nineteen of the 57 (33%) types of bacteria that varied in abundance across race in children are known to be differentially abundant in Black and white adults.

  • Machine learning modeling of childhood microbiome samples distinguished Black vs white vs Asian/Pacific Islander categories and Hispanic vs non-Hispanic categories with 87% accuracy.


"Our results highlight the impetus to increase the diversity of individuals included in studies in the microbiome sciences and support the call for studies investigating how structural racism and other structural inequities affect microbiome variation and health," the authors say.


The study was led by Elizabeth Mallott, PhD, with Washington University in St. Louis, and was published online August 17 in PLOS Biology. Funding for the study was provided by the National Institutes of Health.


The researchers did not attempt to determine which of the race/ethnicity-related variations were connected with positive or negative impacts on health.


The authors have disclosed no relevant financial relationships.

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