title: [Effects of ascorbic acid and citric acid on iron bioavailability in an in vitro digestion/ Caco-2 cell culture model].
abstract: OBJECTIVE
  To study the effects of ascorbic acid and citric acid on iron bioavailability using an in vitro digestion/Caco-2 cell culture model and evaluate the validity of this cell model.
  
  
  METHODS
  This model combined in vitro digestion technique with Fe uptake by Caco-2 cells by utilizing an inserted ring attached to a dialysis membrane to simulate the gastrointestinal environment to allow simultaneous food digestion and uptake processes. Ferritin formation in the Caco-2 cells was measured as the indicator of Fe uptake by exposing Caco-2 cells to the digests containing Fe plus ascorbic acid or citric acid.
  
  
  RESULTS
  When Fe concentration in the digest was below 100 micromol/L, ferritin formation increased with the Fe concentration in the digest. The iron digest containing ascorbic acid exhibited a significant increase in ferritin formation relative to the iron digest containing citric acid. The model was more sensitive to lower iron concentrations when ascorbic acid was present in the digest, while wider range of iron concentration could be assessed by addition of citric acid.
  
  
  CONCLUSIONS
  The in vitro digestion/ Caco-2 cell culture model is a valuable tool for iron bioavailability assessment. Ascorbic acid has a stronger effect than citric acid in promoting iron bioavailability.
authors.affiliation: West China School of Public Health, Sichuan University, Chengdu 610041, China. jil765@163.com
authors.forename: Ji
authors.initials: J
authors.lastname: Lei
authors.forename: Ming-qiu
authors.initials: MQ
authors.lastname: Zhang
authors.forename: Cheng-yu
authors.initials: CY
authors.lastname: Huang
authors.forename: Lin
authors.initials: L
authors.lastname: Bai
authors.forename: Zhong-hu
authors.initials: ZH
authors.lastname: He
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D001682:Biological Availability; D018938:Caco-2 Cells / Q000378:metabolism; D019343:Citric Acid / Q000494:pharmacology*; D005293:Ferritins / Q000096:biosynthesis; D005296:Ferrous Compounds / Q000493:pharmacokinetics; D006801:Humans; D007501:Iron / Q000493:pharmacokinetics*; D008954:Models, Biological
chemical_list: D005296:Ferrous Compounds; D019343:Citric Acid; C020748:ferrous sulfate; D005293:Ferritins; D007501:Iron; D001205:Ascorbic Acid