title: An intervention study of the effects of calcium intake on faecal fat excretion, energy metabolism and adipose tissue mRNA expression of lipid-metabolism related proteins.
abstract: BACKGROUND
  In various observational studies, an inverse relation between calcium intake and body weight has been observed. A possible explanation could be an increased calcium excretion through the faeces caused by an increased dietary calcium intake.
  
  
  OBJECTIVE
  To examine whether an increased calcium intake could lead to changes in faecal fat and energy excretion.
  
  
  METHODS
  Four different isocaloric diets with various calcium contents (400, 1200 and 2500 mg from dairy and 1200 mg from calcium carbonate (1200S)) were administered in a crossover design for 7 days each.
  
  
  METHODS
  Five healthy men and five healthy women (age=28+/-2, body mass index=24.1+/-0.4, body fat%=25.6+/-2.4) were recruited by local announcement.
  
  
  METHODS
  At the end of every intervention period, faecal samples were collected for determination of fat, energy and calcium content, blood samples were obtained for determination of relevant blood parameters; and fat samples were obtained for measurement of the mRNA expression. Furthermore, resting energy expenditure and fat oxidation were measured with the ventilated-hood technique.
  
  
  RESULTS
  We observed a non-significant 56% increase in fat excretion (P=0.159) on the 2500 mg diet, compared to the 400 mg diet. The 2500 mg diet significantly reduced the expression of fatty acid synthase (FAS) mRNA (P<0.05) and the calcium content of the diets significantly affected calcium excretion. Furthermore, we saw a significant decrease of serum triglycerides on the 1200S diet (P<0.05).
  
  
  CONCLUSIONS
  In this study, we observed a trend towards a higher fat excretion on the high-calcium diet, but this difference failed to reach statistical significance. It is possible that the relatively high protein content of the experimental diets increased calcium absorption from the intestine, thus decreasing the amount of calcium available for binding to fat and eliminating possible effects of dietary calcium on fat excretion. Furthermore, we observed decreases in FAS mRNA expression and serum triglycerides as a result of a high calcium intake.
authors.affiliation: Nutrition and Toxicology Research Institute Maastricht, University of Maastricht, Maastricht, The Netherlands. n.boon@hb.unimaas.nl
authors.forename: N
authors.initials: N
authors.lastname: Boon
authors.forename: G B J
authors.initials: GB
authors.lastname: Hul
authors.forename: J H C H
authors.initials: JH
authors.lastname: Stegen
authors.forename: W E M
authors.initials: WE
authors.lastname: Sluijsmans
authors.forename: C
authors.initials: C
authors.lastname: Valle
authors.forename: D
authors.initials: D
authors.lastname: Langin
authors.forename: N
authors.initials: N
authors.lastname: Viguerie
authors.forename: W H M
authors.initials: WH
authors.lastname: Saris
mesh_terms: D017667:Adipocytes / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D002153:Calorimetry, Indirect / Q000379:methods; D018592:Cross-Over Studies; D004032:Diet; D002149:Energy Intake; D004734:Energy Metabolism / Q000187:drug effects*; D064429:Fatty Acid Synthases / Q000096:biosynthesis; D005243:Feces / Q000737:chemistry*; D005247:Feeding Behavior; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014280:Triglycerides / Q000097:blood
chemical_list: D002136:Calcium, Dietary; D012333:RNA, Messenger; D014280:Triglycerides; D064429:Fatty Acid Synthases