Zinc is essential for growth and development in the premature infant yet elevated levels in the diet may interfere with iron absorption. Relative concentrations of zinc/iron vary 2-4 fold in current premature formulas. Therefore, we studied erythrocyte incorporation of Fe58 in 5 premature infants (<2500 g birth weight) receiving either high (1200 ug/kg) or low(300 ug/kg) doses of oral zinc sulphate, concurrently with 300 ug/kg oral Fe58 as chloride with 10 mg/kg vitamin C. In this crossover study, each infant served as their own control and were randomized to receive either the high or low zinc doses 2 weeks apart. Zinc and iron were given at baseline and two weeks later by nasogastric tube in between a regular feed and flushed with saline. No additional vitamins or iron were given on the study day. Iron was extracted from blood samples (at baseline, 2, 4 weeks) by ether extraction and chromatography, then analysed by FAB-SIMS for 58Fe/54Fe ratios. Results indicated high zinc inhibited iron absorption as relative enrichment decreased in each infant, on average, by half (50.2 ± 43%). Sufficient iron in early feeding must take into account the levels of zinc in the diet. Supported by the Medical Research Council of Canada
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(Spon. by Rudy Ozere).
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Friel, J., Fennessey, P., Miller, L. et al. ZINC-IRON INTERACTION IN THE PREMATURE INFANT USING THE STABLE ISOTOPE FE58. † 1840. Pediatr Res 39 (Suppl 4), 309 (1996). https://doi.org/10.1203/00006450-199604001-01864
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DOI: https://doi.org/10.1203/00006450-199604001-01864