Combined impact of pH and organic acids on iron uptake by Caco-2 cells

J Agric Food Chem. 2003 Dec 17;51(26):7820-4. doi: 10.1021/jf030177n.


Previous studies have shown that organic acids have an impact on both Fe(II) and Fe(III) uptake in Caco-2 cell. However, to what extent this effect is correlated with the anion of organic acids per se, or with the resulting decrease in pH, has not yet been clarified. Therefore, we studied the effect of five organic acids (tartaric, succinic, citric, oxalic, and propionic acid) on the absorption of Fe(II) and Fe(III) in Caco-2 cells and compared this with sample solutions without organic acids but set to equivalent pH by HCl. The results showed that the mechanisms behind the enhancing effect of organic acids differed for the two forms of iron. For ferric iron the organic acids promoted uptake both by chelation and by lowering the pH, whereas for ferrous iron the promoting effect was caused only by the lowered pH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caco-2 Cells
  • Carboxylic Acids / pharmacology*
  • Citric Acid / pharmacology
  • Ferric Compounds / metabolism
  • Ferrous Compounds / metabolism
  • Humans
  • Hydrochloric Acid
  • Hydrogen-Ion Concentration
  • Intestinal Absorption / drug effects*
  • Intestinal Mucosa / metabolism
  • Intestines / drug effects
  • Iron / metabolism*
  • Oxalic Acid / pharmacology
  • Propionates / pharmacology
  • Solutions
  • Succinic Acid / pharmacology
  • Tartrates / pharmacology


  • Carboxylic Acids
  • Ferric Compounds
  • Ferrous Compounds
  • Propionates
  • Solutions
  • Tartrates
  • Citric Acid
  • Oxalic Acid
  • Succinic Acid
  • Iron
  • propionic acid
  • Hydrochloric Acid
  • tartaric acid