Current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men

Am J Clin Nutr. 2008 May;87(5):1224-9. doi: 10.1093/ajcn/87.5.1224.


Background: No studies have examined the independent effects of current and longer-term dietary zinc intakes on zinc absorption.

Objective: We determined the effects of current compared with longer-term zinc intake on fractional zinc absorption (FZA).

Design: We studied 9 men whose usual zinc intakes were >11 mg/d. FZA was measured at baseline, depletion (0.6 mg Zn/d for 1 wk and 4 mg Zn/d for 5 wk), and repletion (11 mg Zn/d for 4 wk with 20 mg supplemental Zn/d for first 7 d). During 2 successive days after each dietary period, subjects consumed either adequate-zinc meals (11 mg Zn/d) with a zinc stable isotope tracer for 1 d, followed by low-zinc meals (4 mg Zn/d) with zinc tracer, or vice versa. Five days after oral dosing, a zinc tracer was infused intravenously. FZA was measured with the use of a modified double isotope tracer ratio method with urine samples collected on days 5-7 and 10-12 of absorption studies.

Results: Plasma and urinary zinc did not vary by dietary period. Mean FZA was greater from low-zinc meals than from adequate-zinc meals (60.9% +/- 13.8% compared with 36.1% +/- 8.9%; P < 0.0001), whereas mean total absorbed zinc was greater from adequate-zinc meals than from low-zinc meals (3.60 +/- 0.91 compared with 2.48 +/- 0.56; P < 0.0001), regardless of the longer-term dietary period.

Conclusions: FZA was inversely related to current zinc intake, but there was no detectable effect of longer-term dietary zinc. If longer- term zinc intake does modify FZA, such changes are smaller than those caused by current zinc intake, or they occur only after more severe zinc depletion.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biological Availability
  • Cross-Over Studies
  • Diet*
  • Dose-Response Relationship, Drug
  • Feeding Behavior
  • Humans
  • Indicator Dilution Techniques
  • Intestinal Absorption / drug effects
  • Isotope Labeling
  • Male
  • Middle Aged
  • Nutritional Status*
  • Zinc / administration & dosage*
  • Zinc / blood
  • Zinc / pharmacokinetics*
  • Zinc / urine
  • Zinc Isotopes


  • Zinc Isotopes
  • Zinc