title: Decreased dietary fiber intake and structural alteration of gut microbiota in patients with advanced colorectal adenoma.
abstract: BACKGROUND
  Accumulating evidence indicates that diet is one of the most important environmental factors involved in the progression from advanced colorectal adenoma (A-CRA) to colorectal cancer.
  
  
  OBJECTIVE
  We evaluated the possible effects of dietary fiber on the fecal microbiota of patients with A-CRA.
  
  
  METHODS
  Patients with a diagnosis of A-CRA by pathological examination were enrolled in the A-CRA group. Patients with no obvious abnormalities or histopathological changes were enrolled in the healthy control (HC) group. Dietary fiber intake was assessed in all patients. Short-chain fatty acids (SCFAs) in feces were detected by gas chromatography. The fecal microbiota community was analyzed by 454 pyrosequencing based on 16S ribosomal RNA.
  
  
  RESULTS
  Lower dietary fiber patterns and consistently lower SCFA production were observed in the A-CRA group (n = 344). Principal component analysis showed distinct differences in the fecal microbiota communities of the 2 groups. Clostridium, Roseburia, and Eubacterium spp. were significantly less prevalent in the A-CRA group (n = 47) than in the HC group (n = 47), whereas Enterococcus and Streptococcus spp. were more prevalent in the A-CRA group (n = 47) (all P < 0.05). Butyrate and butyrate-producing bacteria were more prevalent in a subgroup of HC subjects with a high fiber intake than in those in both the low-fiber HC subgroup and the high-fiber A-CRA subgroup (all P < 0.05).
  
  
  CONCLUSIONS
  A high-fiber dietary pattern and subsequent consistent production of SCFAs and healthy gut microbiota are associated with a reduced risk of A-CRA. This trial was registered at www.chictr.org as ChiCTR-TRC-00000123.
authors.affiliation: Division of Gastroenterology and Hepatology, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai Institution of Digestive Disease, Shanghai, China.
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Chen
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Yu
authors.forename: Ji-Lin
authors.initials: JL
authors.lastname: Wang
authors.forename: Yan-Wei
authors.initials: YW
authors.lastname: Lin
authors.forename: Xuan
authors.initials: X
authors.lastname: Kong
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Zhan-Ju
authors.initials: ZJ
authors.lastname: Liu
authors.forename: Yao-Zong
authors.initials: YZ
authors.lastname: Yuan
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Wu
authors.forename: Liang
authors.initials: L
authors.lastname: Zhong
authors.forename: Dian-Chun
authors.initials: DC
authors.lastname: Fang
authors.forename: Weiping
authors.initials: W
authors.lastname: Zou
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Fang
mesh_terms: D000368:Aged; D002087:Butyrates / Q000378:metabolism; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D002849:Chromatography, Gas; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000382:microbiology / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000235:genetics; D004032:Diet; D004043:Dietary Fiber / Q000008:administration & dosage*; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006094:Gram-Positive Bacteria / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008297:Male; D054892:Metagenome; D008875:Middle Aged; D015999:Multivariate Analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D011795:Surveys and Questionnaires
chemical_list: D002087:Butyrates; D004269:DNA, Bacterial; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D012336:RNA, Ribosomal, 16S