title: Faecal steroid excretion in humans is affected by calcium supplementation and shows gender-specific differences.
abstract: BACKGROUND
  Previous human studies on the effect of dietary calcium supplementation on faecal excretion of bile acids (BA) and faecal water concentrations of animal neutral sterols (NSt, cholesterol and its metabolites) lack detailed information about single BA and NSt.
  
  
  OBJECTIVE
  We investigated whether single BA and NSt in faeces and especially in faecal water are affected by calcium supplementation and whether this affects genotoxicity of faecal water. In addition, we differentiated between men and women with regard to the concentrations of BA and NSt in faecal water.
  
  
  METHODS
  Thirty-one healthy volunteers consumed a calcium supplemented bread (1.0 g/day) and a placebo bread, respectively, for 4 weeks in a double-blind, randomised cross-over trial. Faeces were collected quantitatively for 5 days in the last week of each period. NSt and BA were analysed by GC-MS.
  
  
  RESULTS
  Due to calcium supplementation faecal concentrations of lithocholic acid (LCA, 14%, P = 0.008), deoxycholic acid (DCA, 19%, P < 0.001) and 12 keto-deoxycholic acid (12 keto DCA, 29%, P = 0.049) significantly increased whereas BA concentrations in faecal water were only marginally affected. In contrast, concentrations of cholesterol (30%, P = 0.020) and its metabolites coprostanol (43%, P = 0.004), coprostanone (36%, P = 0.003), cholestanol (44%, P = 0.001) and cholestenone (32%, P = 0.038) in faecal water significantly decreased. Total NSt concentration in faecal water was found to be significantly higher in women compared to men (P = 0.018). The genotoxicity of faecal water was neither affected by calcium supplementation nor were there gender-specific differences.
  
  
  CONCLUSIONS
  Dietary calcium supplementation diversely affects BA and NSt in faeces and in faecal water but does not influence the genotoxicity of faecal water in healthy adults.
authors.affiliation: Department of Nutritional Physiology, Institute of Nutrition, Friedrich Schiller University, Dornburger Strasse 24, 07743, Jena, Germany.
authors.forename: Bianka
authors.initials: B
authors.lastname: Ditscheid
authors.forename: Sylvia
authors.initials: S
authors.lastname: Keller
authors.forename: Gerhard
authors.initials: G
authors.lastname: Jahreis
mesh_terms: D000328:Adult; D001647:Bile Acids and Salts / Q000032:analysis; D001939:Bread; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002776:Cholestanes / Q000032:analysis; D004083:Cholestanol / Q000032:analysis; D002778:Cholestanones / Q000032:analysis; D002783:Cholestenones / Q000032:analysis; D002784:Cholesterol / Q000032:analysis; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005243:Feces / Q000737:chemistry*; D005260:Female; D005527:Food, Fortified; D006801:Humans; D008297:Male; D010919:Placebos; D012727:Sex Characteristics; D013261:Sterols / Q000032:analysis*
chemical_list: D001647:Bile Acids and Salts; D002136:Calcium, Dietary; D002776:Cholestanes; D002778:Cholestanones; D002783:Cholestenones; D010919:Placebos; D013261:Sterols; D004083:Cholestanol; D002784:Cholesterol; C007123:coprostanone