Serum zinc and copper levels in healthy middle and higher socio-economic class infants in Cape Town. A longitudinal study during the 1st year of life.

Serum zinc and copper levels were measured using a flame atomic absorption technique in 55 healthy infants and their middle and upper socio-economic class mothers at delivery, and also longitudinally in the infants during the first 12 months of life. Mean cord serum zinc levels (99.50 +/- 27.63 micrograms/100 ml) were 1.5 times higher than maternal serum levels at birth (66.3 +/- 21.0 micrograms/100 ml). The mean serum zinc levels showed no significant change (P greater than 0.05) at each of the study periods. However, the mean serum zinc levels at birth were significantly higher (P less than 0.05), than those after 6 weeks. The infants' levels remained within the normal adult range at all the study periods. The mean cord serum copper levels (34.46 +/- 12.60 micrograms/100 ml) were about one-sixth of the mean maternal serum copper levels at delivery (217.7 +/- 64.39 micrograms/100 ml). The mean serum copper levels increased significantly (P less than 0.05) from birth to 12 months of age. Mean serum copper levels similar to those of normal adults were reached at 12-24 weeks.