The exchangeable zinc pool as a measure of zinc nutritional status in children

ABSTRACT 645 _Poster Session II, Sunday, 5/2 (poster 156)_ INTRODUCTION: The exchangeable zinc pool (EZP) is a mathematical approximation of the mass of the body zinc compartments that

exchange rapidly with plasma zinc. In adults EZP directly correlates with dietary zinc intake, and may be a useful measure of zinc nutrition. Few data exist regardinging the size of the EZP

in children, or its validity as a measure of zinc nutritional status in this population. OBJECTIVE: To examine the relationship between EZP and other measures of zinc nutrition in children,

and to compare the mass of the EZP with estimates previously published for adults. METHODS: Eight healthy girls (mean age 9.7 ±0.6 yr) with habitual zinc intakes between 4 mg/d and 16 mg/d

were studied. Subjects received 0.5 mg of a zinc-70 enriched tracer intravenously. All urine voided 48 to 144 hr after isotope administration was collected and analyzed in 8 hr aliquots.

Blood was drawn by venepuncture at 48, 72, 96, 120 and 144 hr. Plasma and urine zinc-70 enrichment was measured by thermal ionization mass spectrometry, and converted to tracer:tracee ratios

(TTR). TTR was plotted against time and the regression line extrapolated back to time 0 hr (TTR-0). EZP was calculated from the equation, EZP = dose of isotope given / TTR-0. EZP was

calculated for each subject separated from plasma (EZP-pl) and urinary (EZP-ur) enrichments. RESULTS: EZP-pl and EZP-ur were highly correlated (p = 0.009) but EZP-pl was significantly

greater than EZP-ur. (Table) Mean EZP-pl significantly exceeded adult values (mean for adults = 3.2 mg/kg, p = 0.05). EZP-ur was similar to values quoted for adults (mean for adults = 2.7

mg/kg, p = 0.86). Neither EZP-pl nor EZP-ur were significantly related to habitual zinc intake (p = 0.49 and 0.86, respectively), nor to plasma zinc concentration, zinc intake during the

study period, or the subjects age. CONCLUSIONS: The mass of the EZP in children may exceed that in adults, but it does not appear to be a useful measure of zinc nutritional status in this

population. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * USDA/ ARS Children's Nutrition Research Center, and Section of Neonatology, Baylor College of Medicine, Houston, TX Ian J

Griffin & Steven A Abrams Authors * Ian J Griffin View author publications You can also search for this author inPubMed Google Scholar * Steven A Abrams View author publications You can

also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Griffin, I., Abrams, S. The Exchangeable Zinc Pool As

a Measure of Zinc Nutritional Status in Children. _Pediatr Res_ 45, 111 (1999). https://doi.org/10.1203/00006450-199904020-00662 Download citation * Issue Date: 01 April 1999 * DOI:

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