Intakes and excretions of Iron, Copper, and Zinc in the neonatal period

Abstract

Meconium passed during the first 24 hours after birth was collected from 6 babies and analysed for iron, copper, and zinc. The intake and urinary and faecal excretion of the three metals were measured on another 10 babies, all breast-fed, over a three-day period at the end of the first week. Meconium contained an average of 1 7 mg./I00 g. iron and copper and 6 -5 mg./100 g. zinc. The concentration of all three metals was very variable in breast milk and there was no relation between the volume of milk secreted and its composition. All the babies were in negative iron balance: the faeces contained on the average more than 10 times as much iron as the food and the mean loss of iron from the baby's body amounted to 3 -6 mg. a day. Some of the babies were in negative and some in positive copper balance, but all except one were in negative zinc balance. They were losing more than i 00 of the body's total iron and zinc each day. It is not known how long these large negative balances continue, but possible explanations for them are discussed.