Trace element content of human milk during lactation.

Human milk is believed to provide all the nutrients necessary for normal infant growth. The present study is concerned with the evaluation of longitudinal changes in Fe, Cu, Zn, Se, Br, Pb, Rb, and Sr milk contents over a long period of lactation. A total of 140 milk samples from 26 lactating mothers were supplied from the 2nd to the 180th day after delivery of a full-term healthy infant. Cu, Zn, and Se showed a time-dependent decrease, with similar 10-day half-times. Br and Pb showed correlations with time, but the data fitting produced very short (2-3 days) half-times. The Fe, Rb, and Sr contents were constant over the lactation time. After about one month of lactation, trace element contents tend to stabilise, as do other milk components.