Pesticide Residues, Gut Microbiota, and Gastrointestinal Outcomes: A Scoping Review of Human Evidence

Abstract

ABSTRACT Vegetables anchor healthy‐diet recommendations yet are the principal nonoccupational route by which residues of organophosphate (OP), pyrethroid, neonicotinoid, organochlorine (OC), and glyphosate herbicide enter the diet, with the gut microbiota a plausible mediator linking these residues to functional gastrointestinal (GI) and inflammatory bowel outcomes. We conducted a scoping review following the PRISMA extension for Scoping Reviews (PRISMA‐ScR), searching PubMed (2010 to April 2026) with mandatory backward and forward citation tracing for human studies of dietary or biomarker‐confirmed pesticide exposure against gut microbiota, intestinal barrier and inflammation, functional GI disorders, or inflammatory bowel disease (IBD). Risk of bias (RoB) was appraised with ROBINS‐E and Cochrane RoB 2.0, and evidence was synthesized in a 60‐cell pesticide‐class × outcome gap matrix. Twenty‐eight papers were retained; 20 full‐text‐extracted human studies entered the synthesis, populating 20 of 60 cells (33%). The strongest convergent within‐scope signal was OC exposure × IBD, where three cohorts agreed in direction (hazard ratios 1.56–1.61; Faroese risk ratio 3.04 on 37 cases). As a microbiota‐mediation exemplar for an adjacent non‐GI endpoint, the MCMC Nanjing pregnancy cohort linked a pesticide environmental risk score to gestational diabetes (adjusted odds ratio 4.5; 95% CI, 1.4–13.8; internal‐validation area under the curve 0.83), with a Dorea ‐branch microbiota mediating part of the path. Glyphosate × IBD and neonicotinoid × any GI outcome remained empty. RoB centered on Moderate (11 of 22 rated cohorts), with six elevated‐bias contributors. Biomarker‐anchored prospective cohorts targeting the empty cells should be the next research priority.