ABSORPTION AND RETENTION OF COPPER, ZINC, CALCIUM, AND PHOSPHOROUS IN PREMATURE INFANTS

Abstract

72 hour balance studies to determine absorption and retention of copper, zinc, calcium, and phosphorous were done in 2 groups of well, growing, premature infants who were fed one of 2 formulas: Similac Special Care (SSC) with standard concentrations of Cu, (2.1mg/L), Zn, Ca, and PO4 or Clinical Product (CP) identical to SSC, except for a reduced concentration of copper (.8mg/L). Mean gestational age and birth weight of SSC group (GA=30.0 wks., BW=1279gms.) were not significantly different from the CP group (GA=31.2 wks., BW=1478gms.). Weight and post conceptional age (PCA) at time of study were not significantly different between the two groups. (SSC=1522gms. & 34.4 weeks PCA, CP=1576gms. & 33.7 weeks PCA).Although it did not achieve statistical significance, (p=.09) absorption of calcium tended to be slightly higher in the CP group (low Cu); % and absolute absorption of PO4, Cu, and Zn were the same in both groups. The higher copper intake in the SSC group did not increase mean copper absorption. Infants from both groups were in negative copper balance. Zinc balance in all infants was positive and ranged from +9% to +59%. Inutero accretion rates for zinc (>.5mg/kg/d) were achieved in 7 out of 10 infants.