Electrolytic Iron or Ferrous Sulfate Increase Body Iron in Women with Moderate to Low Iron Stores ,

Abstract

Commercial elemental iron powders (electrolytic and reduced iron), as well as heme iron supplements, were tested for efficacy in improving the iron status of women. In a randomized, double-blind trial, 51 women with moderate to low iron stores received daily for 12 wk: 1) placebo, 2) 5 mg iron as heme iron or 50 mg iron as 3) electrolytic iron, 4) reduced iron, or 5) FeSO4. Treatments were provided in 2 capsules (heme carrier) and 3 wheat rolls (other iron sources). Differences in iron status, food nonheme iron absorption, and fecal properties were evaluated. Body iron, assessed from the serum transferrin receptor:ferritin ratio, increased significantly more in subjects administered FeSO4 (127 ± 29 mg; mean ± SEM) and electrolytic (115 ± 37 mg), but not the reduced (74 ± 32 mg) or heme (65 ± 26 mg) iron forms, compared with those given placebo (2 ± 19 mg). Based on body iron determinations, retention of the added iron was estimated as 3.0, 2.7, 1.8, and 15.5%, in the 4 iron-treated groups, respectively. Iron treatments did not affect food iron absorption. The 50 mg/d iron treatments increased fecal iron and free radical–generating capacity in vitro, but did not affect fecal water cytotoxicity. In subjects administered FeSO4, fecal water content was increased slightly but significantly more than in the placebo group. In conclusion, electrolytic iron was ∼86% as efficacious as FeSO4 for improving body iron, but the power of this study was insufficient to detect any efficacy of the reduced or heme iron within 12 wk. With modification, this methodology of testing higher levels of food fortification for several weeks in healthy women with low iron stores has the potential for economically assessing the efficiency of iron compounds to improve iron status.