Abstract
INTRODUCTION: Zinc serves as a cofactor for numerous vital processes across species. Microorganisms that make up the gut microbiome rely on these zinc-dependent mechanisms to perform essential functions, contributing to a diverse and stable microbial environment. Environmental contaminants, such as lead, has been shown to disrupt diversity and stability. The purpose of this study was to determine whether zinc serves as an effect modifier against elevated blood lead levels (BLL) on gut microbiota diversity. METHODS: The 2007-2008 and 2009-2010 NHANES datasets were utilized to conduct a cross-sectional complex survey analysis aimed at determining whether zinc intake acts as a protective factor against changes in microbiome diversity associated with BLL, using enterolactone (ENL) as a biomarker. A multiple linear regression was conducted to evaluate whether an interaction between BLL and zinc intake could predict ENL. The model included fiber intake and BMI as covariates. RESULTS: BMI and fiber intake were identified as covariates. Fiber intake was a confounding variable in the relationship between zinc and ENL levels. Lead was found to decrease ENL levels (p = 0.002). The interaction between zinc and BLL was marginally significant (p = 0.089). CONCLUSION: This study suggests that lead's impact on gut microbial diversity may depend on zinc status. These findings emphasize the importance of accounting for dietary confounders, such as fiber intake, to improve model accuracy and interpretation. While additional research is needed to confirm zinc's potential protective role, public health strategies encouraging adequate zinc and fiber intake may in part help support microbial resilience and reduce lead's effects on the gut microbiota.