title: Calcium absorption is not increased by caseinophosphopeptides.
abstract: BACKGROUND
  One of the suggested health benefits of caseinophosphopeptides (CPPs) is their ability to enhance calcium absorption. This possibility is based on the assumption that they resist proteolysis in the upper gastrointestinal tract and maintain calcium in a soluble form at alkaline pH in the distal ileum.
  
  
  OBJECTIVE
  The effects of CPP-enriched preparations (containing candidate functional food ingredients) on calcium absorption from a calcium lactate drink were tested.
  
  
  METHODS
  A randomized crossover trial was undertaken in 15 adults in whom we measured the absorption of calcium from a calcium lactate drink (drink A: 400 mg Ca as lactate) and 2 preparations enriched with forms of CPP (1.7 g each; drinks B and C). Both drinks B and C contained 400 mg Ca as calcium lactate plus approximately 100 mg CPP-derived calcium). Each volunteer received the 3 drinks in random order. Absorption was measured by the dual-label calcium stable-isotope technique.
  
  
  RESULTS
  The quantity of calcium absorbed was significantly lower from drink A (103 mg) than from drink B (117 mg; P = 0.012) or drink C (121 mg; P = 0.002), which indicated a positive effect of the CPPs. However, because the CPP preparations contributed additional calcium besides that found in the calcium lactate (drink A), fractional absorption of calcium from drink B (23%) was slightly but significantly (P = 0.015) lower than that from drink A (26%).
  
  
  CONCLUSIONS
  The differences in calcium absorption are unlikely to have any biological significance. CPPs are unsuitable as candidate ingredients for functional foods that are designed to deliver improved calcium nutrition.
authors.affiliation: Institute of Food Research, Norwich, United Kingdom.
authors.forename: Birgit
authors.initials: B
authors.lastname: Teucher
authors.forename: Gosia
authors.initials: G
authors.lastname: Majsak-Newman
authors.forename: Jack R
authors.initials: JR
authors.lastname: Dainty
authors.forename: David
authors.initials: D
authors.lastname: McDonagh
authors.forename: Richard J
authors.initials: RJ
authors.lastname: FitzGerald
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Fairweather-Tait
mesh_terms: D000293:Adolescent; D000328:Adult; D001682:Biological Availability; D050071:Bone Density Conservation Agents / Q000493:pharmacokinetics*; D002127:Calcium Isotopes; D002136:Calcium, Dietary / Q000493:pharmacokinetics*; D002364:Caseins / Q000494:pharmacology*; D018592:Cross-Over Studies; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007082:Ileum / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000494:pharmacology; D010748:Phosphopeptides / Q000494:pharmacology*; D013057:Spectrum Analysis; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D050071:Bone Density Conservation Agents; D002127:Calcium Isotopes; D002136:Calcium, Dietary; D002364:Caseins; D010446:Peptide Fragments; D010748:Phosphopeptides; C412562:caseinophosphopeptide 1-25; D014807:Vitamin D; C104450:25-hydroxyvitamin D