Discovery and Validation of Gut Microbiome Features Associated with Dietary Patterns in U.S. Black/African and Hispanic/Latino Populations

Background: Large-scale studies examining dietary patterns and gut microbiome have focused predominantly on European ancestry populations; evidence from other ancestry groups remains limited. Objectives: We conducted a two-stage study to evaluate associations of multiple dietary patterns with gut microbiome diversity and composition among Black/African American adults and validate significant findings in a Hispanic/Latino population in the US. Methods: Included were 514 Black participants from the Southern Community Cohort Study (SCCS) and 2,133 participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Diet was collected by food frequency questionnaires or 24-h dietary recalls at cohort enrollment. Gut microbiome profiling was performed by shotgun metagenomic sequencing of stool samples collected during cohort follow-up. Five dietary patterns - Healthy Eating Index (HEI), Dietary Approaches to Stop Hypertension (DASH), Empirical Dietary Inflammatory Potential (EDIP), Empirical Dietary Index for Hyperinsulinemia (EDIH), and Ultra-Processed Foods (UPF) - were examined for associations with microbiome diversity and composition by linear regression after data transformation and confounders adjustment. Microbial taxa with FDR<0.1 and their constituent lower-level features identified in SCCS were targeted for validation in HCHS/SOL. Results: In SCCS, HEI, DASH, EDIP, or EDIH were associated with the relative abundances of 14 microbial taxa, primarily members of families Coriobacteriaceae and unclassified Firmicutes, as well as species Lactococcus lactis and Clostridium sp. AF20-17LB. Among these, the inverse associations of genus Collinsella and its species C. aerofaciens with HEI or DASH were validated in HCHS/SOL (all P<0.05). Additionally, Collinsella and C. aerofaciens were associated with higher odds of obesity in SCCS (BMI[&ge;] 30 kg/m2; OR [95%CI]:1.24 [1.01, 1.53] and 1.32 [1.07, 1.63], respectively). Conclusions: Healthier dietary patterns were consistently associated with lower abundances of Collinsella and C. aerofaciens in Black/African and Hispanic/Latino Americans. Further research should clarify causal pathway linking diet, gut microbiome, and health outcomes across diverse populations.