title: Impact of oral iron challenges on circulating non-transferrin-bound iron in healthy Guatemalan males.
abstract: BACKGROUND
  Oral iron as a supplement has been associated with adverse health consequences, especially in the context of young children with active malaria. A potential aggravating role of non-transferrin-bound iron (NTBI) has been proposed.
  
  
  METHODS
  NTBI responses in both a fasting and post-oral iron dosing situation were related to serum iron concentration and ferritin status. Fasting and 1, 2, and 3 h postdose serum samples were obtained in conjunction with oral ferrous sulfate supplementation in aqueous solution of 0, 15, 30, 60, 120 and 240 mg Fe in a cohort of 8 healthy Guatemalan men over a 9-week metabolic protocol. Hemoglobin, serum ferritin, percent transferrin saturation, serum iron and NTBI were all measured.
  
  
  RESULTS
  Circulating levels of serum iron and NTBI increased in a graded fashion in response to oral iron, with the relative increment for NTBI slightly greater than that of iron. Detectable NTBI was occasionally measured in fasting specimens, more frequently in subjects with high ferritin status. Post-iron NTBI responses, by contrast, were higher in normal-ferritin subjects in absolute terms, and rose with increasing postabsorptive serum iron responses.
  
  
  CONCLUSIONS
  The appearance and response of circulating NTBI were consistent with recognized principles of iron regulation.
authors.affiliation: Research Center for Nutrition and Food Science, Technische Universität München, Freising, Germany. KSchuemann@schuemann-muc.de
authors.forename: Klaus
authors.initials: K
authors.lastname: Schümann
authors.forename: Sylvia
authors.initials: S
authors.lastname: Kroll
authors.forename: Maria-Eugenia
authors.initials: ME
authors.lastname: Romero-Abal
authors.forename: Niki A
authors.initials: NA
authors.lastname: Georgiou
authors.forename: Jo J M
authors.initials: JJ
authors.lastname: Marx
authors.forename: Günter
authors.initials: G
authors.lastname: Weiss
authors.forename: Noel W
authors.initials: NW
authors.lastname: Solomons
mesh_terms: D000328:Adult; D015331:Cohort Studies; D019587:Dietary Supplements / Q000009:adverse effects; D005293:Ferritins / Q000097:blood; D005296:Ferrous Compounds / Q000008:administration & dosage; D006166:Guatemala; D006397:Hematinics / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007408:Intestinal Absorption; D007501:Iron / Q000097:blood* / Q000378:metabolism; D019266:Iron, Dietary / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D014168:Transferrin / Q000378:metabolism; D055815:Young Adult
chemical_list: D005296:Ferrous Compounds; D006397:Hematinics; D006454:Hemoglobins; D019266:Iron, Dietary; D014168:Transferrin; C020748:ferrous sulfate; D005293:Ferritins; D007501:Iron