Trace Element Balance Study in very Low Brithweight Infants

Abstract

Very low birthweight (VLBW) infants are in danger of developing trace element deficiency, because of their lower stores at birth, their incomplete digestive system and their high rate of synthesis of tissue cells. In this early stage of life several organs (e.g. brain), which are sensitive to trace element imbalances, are differentiating. It is under discussion, whether a deficiency in trace elements is a factor which contribute to typical preterm diseases, as retinopathy of prematury or bronchopulmonary dysplasia. Accordingly any imbalance concerning the trace elements (iron, zinc, selenium and copper) might well influence the antioxidant defence system. Less is known about the trace element needs of the rapid grown VLBW infants during their first three months. To evaluate the adequate supplementation of the trace elements cobalt, copper, iodine, iron, molybdenum, selenium and zinc balance studies were performed in 10 VLBW infants with birthweights less than 1000g. All infants were fed enteral with breast milk plus fortifier. To estimate the trace element uptake from the breast milk urine and faeces were collected during a 72 hour period on week 5 and 10 after birth, respectively. The trace element content in breast milk, serum, urine and faeces was determined by means of ICPmass spectrometry, ICP-atomic emission spectrometry and neutron activation analysis. Nine infants showed negative zinc balance during both collection periods. Two infants developed significant clinical deficiency symptoms. After oral zinc supplementation the clinical symptoms disappeared, but the serum levels of zinc remained below the controls. Of the 10 infants six had negative iron balance despite of iron supplementation. The copper retention of four infants during the second balance period were negative, probably due to low copper intake and inadequate copper reabsortion in the gut. No infant had problems with iodine, molybdenum, selenium and cobalt absorption.