Introduction Zinc is an essential micronutrient used in many biological functions including maintaining the gut microbial diversity. Many environmental factors, such as lead exposure, have been shown to disrupt diversity. The purpose of this study was to determine whether zinc serves as a protective factor against elevated blood lead levels (BLL) on gut microbiome 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 BLL, zinc intake and their interaction, along with additional covariates such as gender, fiber intake and BMI.

Results BMI, fiber intake, and gender were identified as covariates through diagnostic analysis and stepwise regression and were included in the final model. Sequential variable selection revealed that fiber intake was a confounding variable in the relationship between zinc and ENL levels (p = 0.543), while gender was identified as a confounding factor between BLL and ENL levels (p = 0.173). After controlling for fiber intake, zinc intake was not significantly associated with predicting microbiome diversity (p = 0.101). Additionally, no significant interaction between zinc and BLL was observed in predicting ENL levels (p = 0.079).

Conclusion Zinc intake did not play a crucial role in mitigating the toxicity of BLL exposure on gut microbiome diversity. However, the model did reveal important confounding variables, such as gender and fiber intake, which should be considered when using ENL as a biomarker. The public health implications suggest that dietary interventions focusing on fiber intake and managing BMI could be key in maintaining a diverse microbiome.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

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The data utilized in this analysis was sourced from the open dataset provided by the National Health and Nutrition Examination Survey (NHANES), available through the Centers for Disease Control and Prevention (CDC) website. The cleaned data was uploaded as supplementary materials.

https://www.cdc.gov/nchs/nhanes/index.htm