Trace elements, including zinc (Zn) and copper (Cu), are crucial for the functioning of organ systems in the human body, because of their role in several metabolic pathways, growth processes, cell development and protein synthesis. The literature provides little specific information on the content of Zn and Cu in colostrum. Though some studies have been done to estimate their content in early lactation(1-4), the information on concentrations during the initial three days of lactation is scarce(2,4).

A total of 117 postpartum healthy(5) mothers in the maternity ward of Associação de Amparo à Maternidade e Infância volunteered to provide colostrum samples for this study. None of the infants showed malformations or clinically detectable impairment. Samples were collected by manual expression on the 2nd day postpartum at the milk bank of the institution.

Information on the maternal age, parity, occupation, previous miscarriages, smoking and alcohol consumption was obtained. In parallel, household water from individual faucets was analyzed. The specimens were digested with 65% nitric acid. The treatment yielded a yellowish solution containing a small globule of fat that, upon cooling, was removed with a platinum loop. Analyses were carried out using atomic absorption spectrometry.

Statistical tests of Mann–Whitney and Kruskal-Wallis were applied. Differences at P <0.05 were considered statistically significant.

The mean age of participating mothers was 22.1 years and their parity ranged from 1 to 8. As many as 55.6% (n = 65) were housewives, 14.5% were students, and 29.8% had other occupations. Of the 117 participants, 9.4% reported having had at least one miscarriage. Smoking was reported only in 1.7%. Alcohol usage was not reported. No significant differences were found between any pair of these three groups (Table I).

* The intergroup differences are not statistically significant  (P <0.05).

Zn and Cu levels in the water samples were lower than the analytically detectable range.

The average concentration of Zn in colostrum was 1.27 ± 0.78 mg%, whereas reported levels were 0.25-0.9 mg% in the beginning of lactation(6-10). One of the few studies(2) that specifies the day of collection (2nd day postpartum) gives a similar value of 1.15 ± 0.47 mg% for Zn, content in Denver, Colorado, USA, a city with nearly the same population as Campo Grande.

Data on Cu are scarce in the literature. In the present study, the average value of Cu in colostrum was 0.18 ± 0.08 mg%. Lonnerdal(3) reports mean values from 0.04 to 0.06 mg%, whereas other authors describe lower levels, from 0.02 to 0.04 mg%(1-3,7-10). The above mentioned data(2) are also much lower, 0.05 ± 0.03 mg%. Thus, Cu concentrations in colostrum in Campo Grande are almost fourfold higher than in Denver, Colorado. It cannot be from local water, since Cu concetrations in the households supply were insignificant. Nor can it be meat since its consumption in Mato Grosso do Sul in 2005 was 29.5 kg per capita, while in Denver in 1984 – 1988, when Casey’ s data were collected, it was 64 kg.

In the present study, no significant differences in Zn and Cu contents were found regarding parity and history of miscarriage, which is in agreement with the findings of Felley(4) but not with those of Cumming(7) and Kirsten(8).

The authors are indebted to Marcos Antônio Contel Secco for having helped in the preparation of the present article.