Body iron excretion by healthy men and women

Am J Clin Nutr. 2009 Jun;89(6):1792-8. doi: 10.3945/ajcn.2009.27439. Epub 2009 Apr 22.


Background: Iron excretion measured by isotope dilution has been a primary basis for the factorial derivation of recommendations for iron intake, but the results have been available for men only.

Objective: The objective of this study was to confirm iron excretion measurements in healthy men and extend them to women.

Design: The turnover rate of 55Fe that had been administered > or =1 y earlier was determined from blood sampled semiannually for up to 3 y from 53 subjects in the community. Body iron was determined from hemoglobin, serum ferritin, and transferrin receptor. Complete menstrual collections were obtained from 13 women.

Results: The total median (range) iron excretion was 1.18 (0.11-2.07) mg/d for 29 men, 1.58 (0.65-4.88) mg/d for 19 menstruating women, and 0.99 (0.86-1.57) for 5 postmenopausal women. When hormonal contraceptive users were omitted, the median for 15 menstruating women increased to 1.66 mg/d. The distribution of iron excretion was normal for the men and postmenopausal women and was highly skewed for the menstruating women; menstrual iron accounted for 90% of the variation. Iron excretion was not strongly related to body weight. Body iron in menstruating women decreased somewhat (by 4.6%) in the men and tended to increase (by 1.5%) during the study.

Conclusions: The results extend direct iron excretion measurements in men to include similar measurements in women. The results emphasize the wide range of iron excretion in humans, which results in a 40-fold range of requirements for absorbed iron. This trial was registered at as NCT00755105.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Body Weight
  • Female
  • Ferritins / blood
  • Half-Life
  • Hemoglobins / analysis
  • Humans
  • Iron / blood
  • Iron / metabolism*
  • Male
  • Menstruation / metabolism
  • Middle Aged
  • Sex Factors


  • Hemoglobins
  • Ferritins
  • Iron

Associated data