A single 60-mg iron dose decreases zinc absorption in lactating women.
This study determined whether a single 60-mg dose of ferrous sulfate interferes with fractional zinc absorption (FZA) at 7-9 wk of lactation. In a crossover design, 5 exclusively breast-feeding women were given either a single 60-mg iron supplement or no supplement. FZA was measured by analyzing zinc stable isotope tracers ((70)Zn and (67)Zn) in urine samples collected for 7 d after isotope dosing. A 0.7-micromol intravenous (IV) infusion of (70)Zn as ZnCl(2) in saline was followed by a 0.03-mmol oral dose of (67)Zn as ZnCl(2) given with a standardized meal. After a 7-d wash-out period, the supplement given was reversed and a second FZA measurement was taken. FZA was calculated from isotopic enrichments in urine measured by inductively coupled plasma mass spectrometry. Hemoglobin, plasma ferritin and transferrin receptor, and plasma 5'-nucleotidase, plasma zinc and erythrocyte zinc did not differ before the two measurements of zinc absorption. When women were given a single iron supplement, FZA was significantly lower, 21.7 +/- 1.7% compared with 26.9 +/- 2.6% when no supplement was given (P = 0.032). A single 60-mg iron dose significantly decreases FZA during early lactation.
Chung
Carolyn S
CS
Department of Nutrition and Food Science, University of Maryland, College Park, USA.
Nagey
David A
DA
Veillon
Claude
C
Patterson
Kristine Y
KY
Jackson
Robert T
RT
Moser-Veillon
Phylis B
PB
D000042:Absorption / Q000187:drug effects; D000328:Adult; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005296:Ferrous Compounds / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D007774:Lactation / Q000378:metabolism*; D011247:Pregnancy; D015032:Zinc / Q000493:pharmacokinetics* / Q000652:urine
D005296:Ferrous Compounds; C020748:ferrous sulfate; D015032:Zinc