Inositol phosphates influence iron uptake in Caco-2 cells

Erika Skoglund, Bo Lönnerdal, Ann Sofie Sandberg

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Phytate, inositol hexaphosphate (InsP6), may be hydrolyzed to inositol phosphates with lower degree of phosphorylation, i.e., inositol penta- to monophosphates (InsP5-InsP1), during food processing. Each of these lower inositol phosphates exists in different isomeric forms. The objective of this study was to determine if different isomers of InsP3-InsP5 (Ins(1,2,4)P3, Ins(1,2,3)P3, Ins(1,2,6)P3, Ins(1,3,4)P3, Ins(1,2,3,4)P4, Ins(1,2,5,6)P4, Ins(1,2,4,5,6)P5, and Ins(1,3,4,5,6)P5) and InsP6 affect the uptake of iron. We studied the iron absorption in vitro using the human intestinal epithelial cell line, Caco-2. Addition of a 2-fold molar excess of InsP6 or InsP5 in proportion to Fe (1 h incubation at 37 °C) reduced iron uptake by 46-52% (p < 0.001). Neither InsP4 isomers nor InsP3 isomers affected iron uptake significantly at 1 h incubation with a molar InsP:Fe level of 2:1. Iron uptake was shown to not be a function of the isomeric form of inositol phosphates. The inositol phosphate isomers did not seem likely to interact with each other through iron to form more stable iron complexes. At a molar InsP:Fe level of 20:1 an inhibitory effect of InsP4 was found, while InsP3 did not affect the iron absorption even at a 20-fold molar excess.

Original languageEnglish (US)
Pages (from-to)1109-1113
Number of pages5
JournalJournal of Agricultural and Food Chemistry
Issue number3
StatePublished - Mar 1999


  • Caco-2 cells
  • Inositol phosphate isomers
  • Iron absorption
  • Phytate

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)


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