Plasma zinc, copper, and selenium concentrations were determined in 129 full-term infants at birth and at the age of four months by electrothermal or hydride generation atomic absorption spectrometry. Of these, 49 infants were exclusively breast-fed (HM), 45 received various commercially available cow's milk formulae (F) and 35 infants were fed partially hydrolysed whey protein formula (PHF). The results were correlated with hematological, biochemical and somatic data. Plasma zinc values decreased from birth to the age of four months in all three groups (p < 0.001). The plasma Zn level of the babies fed PHF were similar to those of breast-fed infants, whereas in F-fed children the zinc values were significantly lower (PHF, 807 +/- 106; HM, 794 +/- 112; F, 725 +/- 111 micrograms l-1; all the measurements were performed at the age of four months). In infants fed PHF formula there was a negative correlation between plasma zinc and weight or height increments. In agreement with the literature, plasma copper and ceruloplasmin increased significantly within the first four months of life. The plasma copper content was similar in either feeding group. Plasma selenium was low at birth (40 +/- 9 micrograms l-1) and remained constant in breast-fed infants. In infants on PHF there was a steeper decline of plasma Se (20 +/- 6 micrograms l-1) than in infants fed cow's milk formula (29 +/- 9 micrograms l-1). Other parameters of the Se status showed a similar pattern. Despite the different zinc, copper, and selenium supply, plus presumedly different bioavailability, all the infants thrived.(ABSTRACT TRUNCATED AT 250 WORDS)

In 129 term infants at birth and at the age of 4 months, zinc and copper concentrations of plasma and urine were determined by graphite furnace atomic absorption spectrophotometry and the values correlated to other biochemical parameters and somatic data. Of the infants, 49 were exclusively breast-fed, 44 fed with various commercially available cow's milk formula, 35 fed with a hypoallergenic formula (cows's milk whey hydrolysate, commercially available, supplemented with zinc and copper). Plasma zinc values declined from birth to the age of 4 months in all three groups (P < 0.001). In formula fed children, 4 months old, the values (11.1 +/- 1.7 mumol Zn/l) were significantly lower than in breast-fed (12.2 +/- 1.7 mumol Zn/l; P = 0.004) or babies on hypo-allergenic formula (12.4 +/- 1.6 mumol Zn/l; P = 0.0015). In accordance with the literature plasma copper and caeruloplasmin values increased significantly within the first 4 months of life, the plasma levels were similar in either feeding group, only urinary copper excretion was higher in male infants on hypo-allergenic formula (P < 0.03) at the age of 4 months. There were no correlations between zinc or copper values and alkaline phosphatase. In infants on hypo-allergenic formula there was a negative correlation between plasma zinc and weight or height increments. Despite different zinc and copper supply, presumedly different bioavailability, and different plasma zinc values, all infants thrived and weight and length increments were similar in each group.

At birth and at 4 months of age, selenium (Se) values of 129 term infants on three different diets were determined: 50 infants were breast fed (HM), 44 received formula based on cow's milk (F) and 35 were fed "hypoallergenic formula" (PHF) (partially hydrolysed whey protein). The Se status of a group of twins (n = 12) fed "hypoallergenic formula" was compared with the respective group of singletons. All infants had low plasma Se values during early infancy. The plasma Se of breast-fed infants remained stable (plasma Se 43 +/- 8 ng/ml at birth and at 4 months), whereas plasma glutathione peroxidase (GSH-Px) decreased (birth: 107 +/- 29 U/l; 4 months: 62 +/- 11 U/l). The formula-fed infants showed a reduction in plasma Se levels from birth to 4 months (38 +/- 10 ng/ml and 29 +/- 9 ng/ml, respectively). The decrease was even more pronounced in infants fed the "hypoallergenic formula". This group presented the lowest Se values (plasma Se 39 +/- 9 ng/ml at birth; 20 +/- 6 ng/ml at 4 months). Renal excretion of Se was found to be lower in the formula-fed infants (F and PHF) compared with the HM group. There was a significant correlation between plasma and urinary Se (r = 0.62, p = 0.0001). Urinary Se (microgram Se/g creatinine) appeared to be a good indicator of Se intake. Measurements of urine Se might be used as a screening method for the estimation of the Se supply. Weight and length increases in all infants were within the normal range. There were no differences between the different feeding groups.