title: A gluten metabolism study in healthy individuals shows the presence of faecal glutenasic activity.
abstract: OBJECTIVE
  To study the gluten metabolism in healthy individuals and its effect over the intestinal microbial activity.
  
  
  METHODS
  The faeces of eleven healthy subjects were analysed under 4 diet regimens: their normal gluten diet, a strict gluten-free diet (GFD), a GFD with a supplemental intake of 9 g gluten/day and a GFD with a supplemental intake of 30 g gluten/day. Gluten content, faecal tryptic activity (FTA), short-chain fatty acids (SCFAs) and faecal glutenasic activity (FGA) were analysed in faecal samples.
  
  
  RESULTS
  Faecal gluten contents, FTA, SCFAs and FGA varied significantly with different levels of gluten intake in the diet. When high gluten doses (30 g/day) were administered in the diet, SCFA concentrations (70.5 mmoles/kg faeces) were significantly different from those from the GFD period (33.8 mmoles/kg faeces) of the experiment. However, the FTA showed significant differences between the GFD (34 units) and the normal gluten-containing diet (60 units) and also between the GFD and the GFD + 30 g of gluten/day (67 units). When gluten was present in the diet, gluten was detected in the faeces, showing that at least a portion of the gluten ingested is eliminated in the large intestine, providing a substrate for intestinal microbial proteases. We have also shown the presence of faecal glutenasic activity that increased proportionally with the gluten intake in the diet, showing an enzymatic activity of 993 units in DSG, 2,063 units in DSG + 9 g and 6,090 units in DSG + 30 g.
  
  
  CONCLUSIONS
  The activity of the intestinal microbiota is modified by gluten intake in the diet. The incorporation of gluten in the diet increases the activity of a gluten proteolytic activity in the faeces.
authors.affiliation: Área de Microbiología, Universidad de León, 24071, León, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Caminero
authors.forename: Esther
authors.initials: E
authors.lastname: Nistal
authors.forename: Laura
authors.initials: L
authors.lastname: Arias
authors.forename: Santiago
authors.initials: S
authors.lastname: Vivas
authors.forename: Isabel
authors.initials: I
authors.lastname: Comino
authors.forename: Ana
authors.initials: A
authors.lastname: Real
authors.forename: Carolina
authors.initials: C
authors.lastname: Sousa
authors.forename: José M Ruiz
authors.initials: JM
authors.lastname: de Morales
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Ferrero
authors.forename: Leandro B
authors.initials: LB
authors.lastname: Rodríguez-Aparicio
authors.forename: Javier
authors.initials: J
authors.lastname: Casqueiro
mesh_terms: D000328:Adult; D055050:Diet, Gluten-Free; D019587:Dietary Supplements; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry*; D005260:Female; D005983:Glutens / Q000008:administration & dosage* / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D008297:Male; D054892:Metagenome; D010447:Peptide Hydrolases / Q000187:drug effects / Q000378:metabolism; D055815:Young Adult
chemical_list: D005232:Fatty Acids, Volatile; D005983:Glutens; D010447:Peptide Hydrolases