Location: Children's Nutrition Research CenterTitle: Zinc supplementation in children with cystic fibrosis) Author
Submitted to: Pediatric Academic Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/17/2009
Publication Date: 5/4/2009
Citation: Griffin, I.J., Hawthorne, K.M., Seilheimer, D.K., Hiatt, P.W., Abrams, S.A. 2009. Zinc supplementation in children with cystic fibrosis [abstract]. Pediatric Academic Society. Abstract no. 4545.5. Interpretive Summary:
Technical Abstract: Cystic fibrosis (CF) leads to malabsorption of macro- and micronutrients. Symptomatic zinc deficiency has been reported in CF but little is known about zinc homeostasis in children with CF. Zinc supplementation (Zn suppl) is increasingly common in children with CF but it is not without theoretcial risks as it may reduce iron and copper absorption. To examine the effect of Zn suppl on fractional (%) and absolute (mg/d) zinc absorption, and on zinc, copper and iron status in children with CF, and compare these data with those in healthy age-matched controls. Twenty children with CF (age 8-14y) on pancreatic enzyme therapy were randomized to receive 20mg/d zinc as zinc acetate (CF-Zn) or an identical appearing placebo (CF-P). No changes were made to the childrens' diets or to their other medications. After 8wks they were admitted for measurement of plasma zinc, plasma ceruloplasmin (a measure of copper status) and serum ferritin (a measure of iron status) and measurement of zinc absorption. Zinc stable isotopes were administered orally (67Zn, 2mg) and intravenously (70Zn, 0.4mg) and zinc absorption was calculated from the relatively recovery of the oral and intravenous tracers in urine collected 72h after isotope administration, measured by thermal ionization magnetic sector mass spectrometry (TIMS). Ten healthy age-matched controls (CON) were also studied on their usual diet. By design, zinc intake was significantly greater in CF-Zn (mean +/- SEM, 37.4mg/d +/- 1.3) than CF-P (15.5 +/- 1.3, P<0.0001). After 8wk plasma zinc was similar in all 3 groups (CON 88mcg/dL +/- 10; CF-P; 84 +/- 10; CF-Zn; 80 +/- 9; P>0.05). Fractional zinc absorption was greater in CON (21.4 +/- 1.8%) than either CF-P (11.0 +/- 1.8, P=0.0002) or CF-Zn (8.8 +/- 1.5, P<0.0001). Zn suppl did not affect fractional zinc absorption in the CF groups (P=0.35) but did increase absolute zinc absorption by more than 2-fold (3.3 +/- 0.4 mg/d v 1.6 +/- 0.4, P=0.004). However, Zn suppl also lead to a reduced serum ceruloplasmin (25.9mg/dL +/- 1.4 v 30.4 +/- 1.4, P=0.035) and tended to reduce serum ferritin (median 19.5ng/ml v 29; P=0.054 after log-transformation). Fractional zinc absorption was reduced in children with CF and was unaffected by Zn suppl. Zn suppl doubled absolute zinc absorption in children with CF but negatively impacts copper and iron status. Zn suppl of children with CF should not be carried out without careful monitoring of copper and iron status.