Zinc and vitamin A: serum concentrations of zinc and retinol-binding protein (RBP) in healthy adolescents.

The concentrations of serum zinc and retinol-binding protein (RBP) have been studied with special reference to pubertal development in 132 healthy adolescents and young adults (11-26 years of age). The RBP level remained low during the first three of the five stages of puberty (mean, about 30 mg/l). When puberty degree 4 had been reached, the mean RBP level increased to nearly adult values (about 40 mg/l), the boys having somewhat higher levels than the girls. Use of oral contraceptives significantly increased the RBP level. The mean zinc values were rather constant throughout puberty, but boys 13-14 years of age had significantly depressed values. There was a statistically significant correlation between the serum levels of zinc and RBP.