Hydrocarbon Exposure, Gut Dysbiosis, and Health: Mechanisms and Interventions in Oil-Producing Communities

Communities living near oil production face persistent contact with complex hydrocarbon mixtures that reshape the gut microbial ecosystem and influence health. This systematic review integrates evidence from 2015 to 2025 to describe environmental exposure levels, reproducible microbiome alterations, mechanistic links to host biology, population-level health associations, and the promise of nutrition and microbiome-based interventions. The review synthesizes studies that paired measured environmental or biomarker indicators of hydrocarbons with gut microbiome sequencing and functional analyses, and it summarizes quantitative findings, mechanistic experiments, and intervention outcomes. We followed PRISMA guidance and searched PubMed, Scopus, Web of Science, and Embase. Eligible reports included human cohorts, case control studies, and complementary animal models that reported environmental exposures or urinary metabolites alongside 16S rRNA or shotgun metagenomic results. Extracted data covered exposure concentrations across air, water, and soil; sequencing and bioinformatics methods; diversity indices; differential abundance and functional predictions; clinical endpoints; and intervention effects. Where appropriate, effect sizes were harmonized and synthesized. Across oil-producing regions, environmental monitoring documented chronic contamination: ambient BTEX averaged about 45 micrograms per cubic meter, water PAHs averaged near 2.5 milligrams per liter, and soil total hydrocarbons averaged roughly 120 milligrams per kilogram. Microbiome studies consistently reported reduced alpha diversity in exposed groups (median Shannon H’: exposed adults 2.1, exposed children 1.8, controls 3.2) and distinct beta diversity clustering by exposure. Taxonomic patterns included expansion of hydrocarbonoclastic genera and reductions in beneficial commensals, accompanied by predicted declines in short-chain fatty acid pathways. Mechanistic work implicates microbial xenobiotic transformation, oxidative stress, reduced short chain fatty acid production, aryl hydrocarbon receptor signaling, and increased intestinal permeability that favors systemic inflammation. Epidemiologic syntheses associate exposure with higher prevalence of gastrointestinal disorders and childhood malnutrition. Early trials and observational interventions suggest dietary fiber and synbiotic approaches can partially restore diversity and function, but rigorous randomized trials in highly exposed communities remain a priority. Overall the evidence supports combined strategies of exposure reduction surveillance and community tailored nutrition to protect microbial resilience and population health.