Zinc levels in human milk and umbilical cord blood.

Zinc levels were determined in human milk and umbilical cord blood samples collected in the Rijeka Clinical Hospital during the period from September 1995 to January 1996. The average concentrations of zinc were 4.98 +/- 2.53 mg/l in breast milk (range: 1.69-11.60 mg/l) and 1.18 +/- 0.21 mg/l in umbilical cord blood (range: 0.87-1.91 mg/l). Results of group comparisons regarding mothers' age, parity, residence and smoking habits indicate that parity affected Zn levels in both, breast milk and umbilical cord blood, with higher content found in primiparae. Younger mothers (aged < or = 25 years) also had higher levels of Zn in breast milk compared to those whose age was > 25 years. Residence and smoking habits did not seem to have any impact on Zn concentrations in biological tissues studied. A weak association between umbilical cord blood Zn levels and anthropometric measurements of newborns, like birthweight and head circumference, is also observed.