title: Effect of the ratio of casein phosphopeptides to calcium (w/w) on passive calcium transport in the distal small intestine of rats.
abstract: OBJECTIVE
  We investigated the influence of different ratios between casein phosphopeptides and calcium (CPP/Ca) in intestinal lumen on passive Ca transport across the distal small intestine of rats in vitro.
  
  
  METHODS
  We measured the amounts of passive Ca absorbed across the everted distal small intestine of rats with the use of radioactive 45Ca as tracer. Four CPP/Ca ratios (5, 10, 15, and 20 w/w) and three mineral concentrations (4, 8, and 12 mmol/L) were tested on groups of six rats.
  
  
  RESULTS
  We found a significant effect of the CPP/Ca ratio on mineral absorption (P < 0.001). The amounts of Ca absorbed increased from a ratio of 5 to a ratio of 15 and decreased with a ratio of 20, with a similar trend for every concentration tested. The more evident effect was found with the concentration of 12 mmol/L of Ca (P < 0.001 to 0.05).
  
  
  CONCLUSIONS
  The positive effect of CPPs on passive Ca absorption seems to depend on the relative amounts of both species in intestinal lumen. In this study, the ratio 15 was identified as the most efficient at increasing mineral transport. This evidence might be considered before suggesting CPP as a Ca dietary integrator, although more studies in vitro and in vivo are needed.
authors.affiliation: Department of Food Science and Microbiology, University of Milan, Italy. daniela.erba@unimi.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Erba
authors.forename: Salvatore
authors.initials: S
authors.lastname: Ciappellano
authors.forename: Giulio
authors.initials: G
authors.lastname: Testolin
mesh_terms: D000284:Administration, Oral; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D002132:Calcium Radioisotopes; D002364:Caseins / Q000008:administration & dosage* / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010748:Phosphopeptides / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002132:Calcium Radioisotopes; D002364:Caseins; D010748:Phosphopeptides; D002118:Calcium