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.

Serum zinc and copper levels in healthy South African women at term and during the first year after childbirth.

Serum zinc and copper levels were measured longitudinally in 55 healthy middle and upper socio-economic group white mothers living in Cape Town from the birth of the baby to 12 months after parturition. Mean maternal serum zinc levels showed a significant rise (P less than 0.05) from delivery (66.34 +/- 21.07 micrograms/100 ml) to 12 weeks (87.88 +/- 15.93 micrograms/100 ml), but no further changes were detected at 24, 36 and 52 weeks after parturition. The mean maternal serum copper levels decreased from 217.73 +/- 64.34 micrograms/100 ml at delivery to 141.65 +/- 45.60 micrograms/100 ml at 12 weeks (P less than 0.05); they remained constant at all the other sampling periods. No differences (P greater than 0.05) were noted at all the different sampling periods between mean serum zinc levels of primiparous and multiparous mothers, but mean serum copper levels were significantly higher (P less than 0.05) in the primiparas. The mean serum zinc and copper levels of healthy white South African mothers at delivery and 12 months after parturition correspond with those for Northern American mothers. Normal non-pregnant adult serum zinc and copper levels were attained within 12 weeks of delivery.

Zinc and copper levels in the breast-milk of Cape Town mothers.

Zinc and copper levels were measured longitudinally in the breast-milk of 55 healthy South African women from the middle and upper socio-economic classes. The mean foremilk zinc levels showed a significant fall (P less than 0,05) from 652,9 +/- 240,7 micrograms/dl at 3 days after delivery to 413,3 +/- 143,0 micrograms/dl at 7 days and 228,1 +/- 136,1 micrograms/dl at 6 weeks. Lower foremilk zinc levels were obtained at 36 weeks (64,3 +/- 50,0 micrograms/dl). In contrast, foremilk copper levels were low at 3 days (57,0 +/- 74,8 micrograms/dl), with a gradual decline to very low levels (28,0 +/- 29,7 micrograms/dl) at 36 weeks. No differences were detected between the fore- and hindmilk zinc and copper levels at any stage of lactation studied (P greater than 0,05).

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.

The prevalence of iron deficiency in apparently healthy Cape coloured infants.

In order to obtain a more accurate picture of the prevalences of anaemia, iron deficiency anaemia, haematological iron deficiency and diminished iron stores, 240 Cape Coloured infants from the lower socio-economic groups were studied. Anaemia was diagnosed in 42 infants (17,5%), iron deficiency anaemia in 81 (34%), and haematological iron deficiency in 28%; 64 (27%) showed evidence of diminished iron stores. The findings indicate that iron deficiency was a common problem in the infants studied, and the same probably also applies to the community at large.