Zinc and copper balance in children on continuous ambulatory peritoneal dialysis

We monitored serum zinc and copper levels for 4 months in six patients treated with continuous ambulatory peritoneal dialysis (CAPD). Zinc and copper fluxes were studied during a single dialysis exchange and over a 3-day period. Routine oral trace element supplements were then discontinued for 2 months. Serum zinc levels declined but serum copper levels remained unchanged. One month after oral supplements had been restarted, serum zinc levels returned to normal and serum copper levels rose above initial values. Zinc and copper concentrations in dialysis exchange indicated that the patients absorbed zinc and lost copper in significant amounts. The patients had poor dietary intakes of both minerals. These data suggest that patients treated with CAPD benefit from oral zinc supplementation.