Serum zinc and copper levels in the 1st year of life

Zinc and copper concentrations in the serum of 240 healthy infants aged 1-12 months were measured by the atomic absorption spectrophotometric method. The study was designed so that on completion there would be 20 infants in each of 12 groups according to age by month. The mean serum zinc levels remained fairly constant in all the age groups except for a significant fall from levels at 1 month (77,11 +/- 12,85 micrograms/dl) to those at 2 months of age (66,60 +/- 15,18 micrograms/dl) (P less than 0,025). Another significant decline in serum zinc levels was present between 4 and 5 months of age (P less than 0,05), which was followed by a significant increase between 5 and 6 months of age (P less than 0,05). The infants' mean serum zinc levels were lower than those of normal adults at all ages (P less than 0,05). The mean serum copper levels were low at 1 month of age (71,17 +/- 17,30 micrograms/dl), and increased significantly between 1 and 2 months (P less than 0,001) and 3 and 4 months of age (P less than 0,02). Mean serum copper levels similar to those of adults were reached at 4 months of age. These levels remained fairly constant from 5 months of age onwards, the only significant decline being noted at between 7 and 8 months of age (P less than 0,05). The present study substantiates previous findings that a specific pattern of change in serum copper concentrations which differs from the trend in serum zinc levels occurs in infants after birth. To detect zinc and copper depletion it is important to interpret serum concentrations in relation to normal values for age.