title: The effect of unfiltered coffee on potential biomarkers for colonic cancer risk in healthy volunteers: a randomized trial.
abstract: BACKGROUND
  Epidemiologic studies suggest that coffee use might protect against colorectal cancer. Inconsistencies as to the effect of coffee use and colorectal cancer between epidemiologic studies might be related to the type of coffee brew.
  
  
  OBJECTIVE
  We studied the effect of unfiltered coffee consumption on putative biomarkers for colonic cancer risk.
  
  
  METHODS
  A total of 64 healthy volunteers (31 men and 33 women), with a mean age of 43 +/- 11 years were randomly assigned to two groups in a crossover design, with two intervention periods of 2 weeks separated by a washout period of 8 weeks. Treatments were 1 L of cafetière (French press) coffee daily or no coffee. At the end of each intervention period, fasting blood samples, colorectal biopsies and 48 h faeces were collected.
  
  
  RESULTS
  No effect of coffee on colorectal cell proliferation, assayed by estimating the Proliferating Cell Nuclear Antigen labelling index, was seen. Additionally, no effects were seen on the concentrations of faecal soluble bile acids and colorectal mucosal glutathione S-transferase activity. However, unfiltered coffee significantly increased the glutathione content in the colorectal mucosa by 8% and in plasma by 15%. Other aminothiols in plasma also increased on coffee.
  
  
  CONCLUSIONS
  Unfiltered coffee does not influence the colorectal mucosal proliferation rate, but might increase the detoxification capacity and anti-mutagenic properties in the colorectal mucosa through an increase in glutathione concentration. Whether this effect indeed contributes to a lower colon cancer risk remains to be established.
authors.affiliation: Department of Gastroenterology and Hepatology, University Hospital Nijmegen, The Netherlands. m.grubben@gastro.azn.nl
authors.forename: M J
authors.initials: MJ
authors.lastname: Grubben
authors.forename: C C
authors.initials: CC
authors.lastname: Van Den Braak
authors.forename: R
authors.initials: R
authors.lastname: Broekhuizen
authors.forename: R
authors.initials: R
authors.lastname: De Jong
authors.forename: L
authors.initials: L
authors.lastname: Van Rijt
authors.forename: E
authors.initials: E
authors.lastname: De Ruijter
authors.forename: W H
authors.initials: WH
authors.lastname: Peters
authors.forename: M B
authors.initials: MB
authors.lastname: Katan
authors.forename: F M
authors.initials: FM
authors.lastname: Nagengast
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000302:isolation & purification; D003069:Coffee / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D018592:Cross-Over Studies; D005243:Feces / Q000737:chemistry; D005260:Female; D005374:Filtration; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008517:Phytotherapy; D018809:Proliferating Cell Nuclear Antigen / Q000302:isolation & purification
chemical_list: D014408:Biomarkers, Tumor; D003069:Coffee; D018809:Proliferating Cell Nuclear Antigen; D005982:Glutathione Transferase