New insights about iron bioavailability inhibition by zinc

Nutrition. 2007 Apr;23(4):292-5. doi: 10.1016/j.nut.2007.01.006. Epub 2007 Mar 13.

Abstract

Objective: We measured the effects of lower and higher doses of zinc (Zn) given as an aqueous solution on the bioavailability of iron (Fe).

Methods: Fourteen healthy subjects received a solution with 0.5 mg of elemental Fe as ferrous sulfate given alone or with 0.59 mg of Zn as zinc sulfate (molar ratio Zn:Fe 1:1). Fourteen days after they received a second solution with 10 mg of Fe given alone or with 11.71 mg of Zn (molar ratio Zn:Fe 1:1). Iron bioavailability was assessed by erythrocyte incorporation of iron radioisotopes (55)Fe and (59)Fe.

Results: No significant effect of Zn on Fe bioavailability was observed at lower doses; however, at higher doses Fe bioavailability was inhibited by 56% (P < 0.001, repeated measures analysis of variance).

Conclusion: The inhibitory effect of Zn on Fe bioavailability depends on the total amount of both minerals present in the intestinal lumen. This fact should be considered when designing a supplementation program if Fe and Zn are to be provided together.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Anemia, Iron-Deficiency / drug therapy
  • Biological Availability
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Erythrocytes / chemistry*
  • Female
  • Humans
  • Intestinal Absorption / drug effects
  • Iron Radioisotopes
  • Iron, Dietary / pharmacokinetics*
  • Trace Elements / pharmacology*
  • Zinc / pharmacology*

Substances

  • Iron Radioisotopes
  • Iron, Dietary
  • Trace Elements
  • Zinc