饮食是肠道微生物群的主要调节因素，肠道微生物群在健康状况中起着关键作用，包括结直肠癌（CRC）的发展。多项研究和荟萃分析证实了某些膳食因素和外源性物质摄入与CRC发病率的关联。然而，这些膳食因素如何影响肠粘膜损伤的初期阶段尚不明确。本研究旨在探讨相关膳食因素与对照个体和诊断为肠息肉患者的肠道微生物群的关联。共招募了60名志愿者，根据结肠镜标准分型，并使用食物频率问卷（FFQ）进行采访。确定每位志愿者的营养状况，并量化膳食外源物的摄入量。通过16S rRNA基因测序获得粪便微生物群分类群相对丰度。膳食因素和外源性物质与粪便微生物群组成的关联显示出根据临床诊断组存在差异。我们的研究结果表明，对照组中摄入红肉（≥50 g/天）和总多环芳烃（PAHs）（≥0.75 μg/天）与Bacteroidaceae科的相对丰度减少和Coriobacteriaceae科的相对丰度增加相关。摄入杂环胺类物质2-氨基-1-甲基-6-苯基咪唑（4,5-b）嘧啶（PhIP）（≥40 ng/天）和2-氨基-3,8-二甲基咪唑（4,5,f）喹噁啉（MeIQx）（≥50 ng/天）与控制诊断组中Akkermansiaceae科相对丰度减少相关。此外，亚硝基化合物（NOCs）、亚硝酸盐（≥1.69 mg/天）和N-亚硝基二甲胺（NDMA）（≥0.126 μg/天）与Bifidobacteriaceae科的相对丰度减少相关。息肉组中酒精摄入（≥12 g/天）与Peptostreptococcaceae科的相对丰度增加和Veillonellaceae科的相对丰度减少相关。此外，线性回归分析使我们能够确定酒精、钙、生物活性化合物如黄酮类、醒目类、纤维素、酚酸类或总多酚类以及膳食外源性物质如PhIP和MeIQx、N-亚硝基吡咯啉（NPYR）或总PAHs作为粪便微生物群组丰度的潜在预测因子。这些结果表明，根据临床诊断组，奶类、红肉、加工肉和酒精的摄入以及多酚类、膳食PAHs、HAs和NOCs的摄入与肠道微生物群的特定群组相关。

Diet is a major modulator of gut microbiota, which plays a key role in the health status, including colorectal cancer (CRC) development. Several studies and meta-analyses have evidenced an association of certain dietary factors and xenobiotic intake with the incidence of CRC. Nevertheless, how these dietary factors impact the first stages of intestinal mucosa damage is still uncertain. This study aimed at exploring the associations of relevant dietary factors with the gut microbiota of control individuals and subjects diagnosed with intestinal polyps. A total of 60 volunteers were recruited, clinically classified according to colonoscopy criteria and interviewed using food frequency questionnaires (FFQs). The nutritional status of each volunteer was determined and the intake of dietary xenobiotics was quantified. The relative abundance of faecal microbiota taxonomic groups was obtained through 16S rRNA gene sequencing. The association of dietary factors and xenobiotics with faecal microbiota composition showed differences according to the clinical diagnosis group. Our results showed that the intake of red meat (≥50 g day-1) and total polycyclic aromatic hydrocarbons (PAHs) (≥0.75 μg day-1) was associated with a decreased abundance of the family Bacteroidaceae and an increased abundance of Coriobacteriaceae in control subjects. The intake of the heterocyclic amines 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) (≥40 ng day-1) and 2-amino-3,8 dimethylimidazo(4,5,f) quinoxaline (MeIQx) (≥50 ng day-1) was associated with a decreased abundance of Akkermansiaceae in the control diagnosis group. Moreover, N-nitroso compounds (NOCs), nitrites (≥1.69 mg day-1) and N-nitrosodimethylamine (NDMA) (≥0.126 μg day-1) were associated with a decreased abundance of Bifidobacteriaceae. The intake of ethanol (≥12 g day-1) in the polyps group was associated with an increased abundance of Peptostreptococcaceae and a decreased abundance of Veillonellaceae. Moreover, linear regression analyses allowed us to identify ethanol, calcium, bioactive compounds such as flavonoids, stilbenes, cellulose, phenolic acids or total polyphenols, and dietary xenobiotics such as PhIP and MeIQx, the NOC N-nitrosopyrrolidine (NPYR) or the total PAHs as potential predictors of faecal microbiota group abundances. These results indicated that the consumption of milk, red meat, processed meat and ethanol and the intake of polyphenols, dietary PAHs, HAs and NOCs are associated with specific groups of the intestinal microbiota, depending on the clinical diagnosis group.