title: Effect of high-dose iron supplements on fractional zinc absorption and status in pregnant women.
abstract: BACKGROUND
  Women have an increased risk of iron deficiency during pregnancy because of the demands of the developing fetus. Iron supplements are commonly advocated as a prophylactic treatment and are generally taken with meals to reduce side effects, but iron can interfere with the absorption of zinc.
  
  
  OBJECTIVE
  The aim was to determine the effect of consuming an iron supplement (100 mg Fe/d as ferrous gluconate) with meals from 16 wk gestation to term on zinc status and absorption.
  
  
  METHODS
  Stable-isotope techniques were used to measure zinc status (exchangeable zinc pool, EZP) and fractional zinc absorption (FZA) in early and late pregnancy from a meal consumed at a different time from that of iron supplement or placebo consumption in 6 women given iron supplements and 7 given a placebo.
  
  
  RESULTS
  FZA increased during pregnancy, independent of iron supplementation. FZA was significantly higher (P < 0.001) at week 34 than at weeks 16 and 24, and urinary zinc excretion was higher at week 34 than at week 16 (P = 0.02). The size of the EZP remained unchanged throughout pregnancy and was unaffected by iron supplementation. The iron status of iron-supplemented women was higher than that of the placebo group.
  
  
  CONCLUSIONS
  In iron-replete pregnant women who consumed a Western diet, no detectable adverse effects on zinc metabolism were observed after ingestion of 100 mg Fe/d. An increase in the efficiency of zinc absorption was observed during late pregnancy.
authors.affiliation: Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Harvey
authors.forename: Jack R
authors.initials: JR
authors.lastname: Dainty
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Hollands
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Bull
authors.forename: Jurian A
authors.initials: JA
authors.lastname: Hoogewerff
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Foxall
authors.forename: Liadhan
authors.initials: L
authors.lastname: McAnena
authors.forename: J J
authors.initials: JJ
authors.lastname: Strain
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Fairweather-Tait
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D019266:Iron, Dietary / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D009752:Nutritional Status; D011247:Pregnancy / Q000378:metabolism*; D011295:Prenatal Care; D016037:Single-Blind Method; D015032:Zinc / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine
chemical_list: D019266:Iron, Dietary; D015032:Zinc