《农药残留对肠道微生物群系和人类健康的影响》-110页_4mb

The Impact of Pesticide Residues on the Gut Microbiome and Human Health: A Food Safety Perspective

Introduction and Background

Pesticides are widely used in agriculture to manage pests, but their residues pose concerns for human health through contamination of food. This review examines how chronic exposure to pesticide residues affects the gut microbiome, a complex microbial community in the gastrointestinal tract, and its role in human health. The gut microbiome influences digestion, immune function, and metabolism, and alterations can contribute to non-communicable diseases (NCDs) like diabetes, obesity, and inflammatory disorders. Growing evidence links pesticide exposure to gut dysbiosis, highlighting the need for better integration of microbial data in risk assessment.

###Methodology
A systematic literature review was conducted using databases like PubMed, Web of Science, and Scopus to identify peer-reviewed articles published between 2019 and 2020. The search focused on keywords such as "gut microbiome," "pesticides," and specific pesticide categories or chemicals. Studies were screened by title, abstract, and full text for relevance, focusing on experimental and observational research. Doses were normalized to acceptable daily intake (ADI) using reference values from regulatory bodies like FAO/WHO JMPR. Most studies used rodent models, with common pesticides being glyphosate and chlorpyrifos.

###Key Findings

• Microbiome Alterations: Pesticide exposure consistently disrupts gut microbiome composition and diversity, with dose-dependent effects observed in many studies. Herbicides (e.g., glyphosate, 2,4-D) and organophosphates (e.g., chlorpyrifos, diazinon) showed significant changes in microbial abundance and diversity.
• Health Implications: Disruptions include increased pathogenic bacteria, reduced beneficial species (e.g., Lactobacillus, Faecalibacterium), altered production of short-chain fatty acids (SCFAs), and changes in host metabolism (e.g., lipid and glucose dysregulation). Long-term exposure may contribute to neurobehavioral issues, endocrine imbalances, and inflammatory disorders.
• Causality and Mechanisms: Only a few studies established direct causal links using methods like fecal transplants or microbiota-deficient models. The role of pesticides in modulating host susceptibility to diseases remains largely associative, due to challenges in distinguishing physiological adaptations from pathological changes.
• Impact of Mixtures and Formulations: Humans are exposed to multiple pesticides in food, yet few studies investigate combinations. Commercial formulations often include adjuvants that enhance toxicity, exacerbating microbiome dysbiosis.
• Dosing and Models: Experimental doses are frequently set high (up to thousands of times ADI), potentially reducing ecological relevance. Rodent models are widely used, but variations in genetic background, age, and other factors complicate comparisons. Gut microbiome dynamics require longitudinal sampling for accurate assessment.

Provides insights into the biological interactions between pesticides and microbiota, underscoring that while many studies detect changes, translating them to human health risks demands refinement.

###Conclusion and Recommendations
Pesticide residues impact gut microbiome homeostasis, potentially contributing to NCDs, though causal links remain weak due to methodological limitations. Future efforts should focus on:

1. Investigation Gaps: Study human-relevant doses, chronic low-level exposures, and diverse populations using standardized models and parameters.
2. Causality Testing: Employ germ-free animal models, fecal transplants, and mechanistic studies to verify causation.
3. Risk Assessment Integration: Develop guidelines for incorporating microbiome data into chemical risk evaluations, enhancing predictive models and food safety policies.