Sugars increase non-heme iron bioavailability in human epithelial intestinal and liver cells

PLoS One. 2013 Dec 10;8(12):e83031. doi: 10.1371/journal.pone.0083031. eCollection 2013.

Abstract

Previous studies have suggested that sugars enhance iron bioavailability, possibly through either chelation or altering the oxidation state of the metal, however, results have been inconclusive. Sugar intake in the last 20 years has increased dramatically, and iron status disorders are significant public health problems worldwide; therefore understanding the nutritional implications of iron-sugar interactions is particularly relevant. In this study we measured the effects of sugars on non-heme iron bioavailability in human intestinal Caco-2 cells and HepG2 hepatoma cells using ferritin formation as a surrogate marker for iron uptake. The effect of sugars on iron oxidation state was examined by measuring ferrous iron formation in different sugar-iron solutions with a ferrozine-based assay. Fructose significantly increased iron-induced ferritin formation in both Caco-2 and HepG2 cells. In addition, high-fructose corn syrup (HFCS-55) increased Caco-2 cell iron-induced ferritin; these effects were negated by the addition of either tannic acid or phytic acid. Fructose combined with FeCl3 increased ferrozine-chelatable ferrous iron levels by approximately 300%. In conclusion, fructose increases iron bioavailability in human intestinal Caco-2 and HepG2 cells. Given the large amount of simple and rapidly digestible sugars in the modern diet their effects on iron bioavailability may have important patho-physiological consequences. Further studies are warranted to characterize these interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Availability
  • Caco-2 Cells
  • Dietary Sucrose / chemistry
  • Epithelium / drug effects*
  • Ferritins / chemistry
  • Ferrozine / chemistry
  • Fructose / chemistry
  • Glucose / chemistry
  • Hep G2 Cells
  • Humans
  • Intestines / drug effects*
  • Iron / pharmacokinetics*
  • Liver / drug effects*
  • Nutritive Sweeteners / chemistry
  • Phytic Acid / chemistry
  • Sucrose / chemistry
  • Tannins / chemistry
  • Zea mays

Substances

  • Dietary Sucrose
  • Nutritive Sweeteners
  • Tannins
  • Ferrozine
  • Fructose
  • Sucrose
  • Phytic Acid
  • Ferritins
  • Iron
  • Glucose

Grant support

This work was supported by the University of Greenwich School of Science. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.