title: Iron status and food matrix strongly affect the relative bioavailability of ferric pyrophosphate in humans.
abstract: BACKGROUND
  Although ferric pyrophosphate is a promising compound for iron fortification of foods, few data are available on the effect of food matrices, processing, and ascorbic acid on its bioavailability.
  
  
  OBJECTIVE
  We compared the relative bioavailability (RBV) of ferrous sulfate in an experimental form of micronized dispersible ferric pyrophosphate (MDFP) in a wheat-milk infant cereal given with and without ascorbic acid with the RBV of MDFP from a processed and unprocessed rice meal.
  
  
  METHODS
  A crossover design was used to measure iron absorption in young women (n = 26) from test meals fortified with isotopically labeled [57Fe]-MDFP and [58Fe]-ferrous sulfate, based on erythrocyte incorporation of stable isotope labels 14 d later.
  
  
  RESULTS
  Geometric mean iron absorption from the wheat-based meal fortified with MDFP was 2.0% and that from the meal fortified with ferrous sulfate was 3.2% (RBV = 62). The addition of ascorbic acid at a molar ratio of 4:1 to iron increased iron absorption from MDFP to 5.8% and that from ferrous sulfate to 14.8% (RBV = 39). In the rice meals, mean iron absorption from MDFP added to the rice at the time of feeding was 1.7%, and that from ferrous sulfate was 11.6% (RBV = 15). The mean iron absorption from MDFP extruded into artificial rice grains was 3.0% and that from ferrous sulfate in unprocessed rice was 12.6% (RBV = 24). Sixteen of 26 subjects were iron deficient. Iron status was a highly significant predictor of the RBV of MDFP (P < 0.001).
  
  
  CONCLUSIONS
  RBV of the experimental MDFP varied markedly with food matrix and iron status. Assigning a single RBV value to poorly soluble compounds may be of limited value in evaluating their suitability for food fortification.
authors.affiliation: Human Nutrition Laboratory, Institute of Food Science and Nutrition, Swiss Federal Institute of Technology, Zürich, Switzerland. diego.moretti@ilw.agrl.ethz.ch
authors.forename: Diego
authors.initials: D
authors.lastname: Moretti
authors.forename: Michael B
authors.initials: MB
authors.lastname: Zimmermann
authors.forename: Rita
authors.initials: R
authors.lastname: Wegmüller
authors.forename: Thomas
authors.initials: T
authors.lastname: Walczyk
authors.forename: Christophe
authors.initials: C
authors.lastname: Zeder
authors.forename: Richard F
authors.initials: RF
authors.lastname: Hurrell
mesh_terms: D000042:Absorption; D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D001682:Biological Availability; D018592:Cross-Over Studies; D011756:Diphosphates / Q000378:metabolism / Q000493:pharmacokinetics*; D005260:Female; D005293:Ferritins / Q000097:blood; D005296:Ferrous Compounds / Q000378:metabolism / Q000493:pharmacokinetics*; D005502:Food; D005511:Food Handling / Q000379:methods*; D005527:Food, Fortified; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects; D007501:Iron / Q000378:metabolism / Q000493:pharmacokinetics*; D007503:Iron Isotopes; D009752:Nutritional Status; D012275:Oryza / Q000737:chemistry; D014908:Triticum / Q000737:chemistry
chemical_list: D000975:Antioxidants; D011756:Diphosphates; D005296:Ferrous Compounds; D007503:Iron Isotopes; C020748:ferrous sulfate; D005293:Ferritins; D007501:Iron; D001205:Ascorbic Acid; C049051:ferric pyrophosphate