Effect of daily versus twice weekly long-term iron supplementation on iron absorption and status in iron-deficient women: a stable isotope study

Clin Biochem. 2006 Jul;39(7):700-7. doi: 10.1016/j.clinbiochem.2006.02.008. Epub 2006 Apr 5.


Objectives: This work aims at studying the effect of daily versus twice weekly long-term Fe supplementation on Fe absorption and status in Fe-deficient women.

Design and methods: The study design is a randomized controlled open study carried out in the Internal Medicine Department, CHU de Clermont-Ferrand, France. Twenty-four young women participated in this study and were randomized into two groups: Group 1 received 50 mg Fe daily, and group 2 received 50 mg Fe twice weekly for 3 months. On day 10 (D10) and on day 90 (D90) of Fe supplementation, blood samples were obtained, and women received orally about 5 mg of 57Fe, and blood was sampled at different times over 24 h. The 57Fe absorption was evaluated by calculating the areas under the curves (AUC). Fe and oxidative stress status were also assessed.

Results: 57Fe absorption was similar in both groups on D10 but was greatly decreased in Group 1 and remained high in Group 2 on D90. Fe status was more improved in Group 1 than in Group 2. Oxidative stress status remained statistically unchanged.

Conclusions: Our study shows that daily Fe supplementation is able to correct an Fe deficiency much more than twice weekly Fe supplementation in young women.

Publication types

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

MeSH terms

  • Absorption
  • Adolescent
  • Adult
  • Area Under Curve
  • Body Weight
  • Deficiency Diseases / blood
  • Deficiency Diseases / drug therapy*
  • Drug Administration Schedule
  • Female
  • Ferritins / blood
  • Ferritins / drug effects
  • Humans
  • Iron / administration & dosage*
  • Iron / blood
  • Iron / therapeutic use*
  • Oxidative Stress
  • Treatment Outcome


  • Ferritins
  • Iron