Mineral and trace element content of human transitory milk indentified with inductively coupled plasma atomic emission spectrometry

Mineral and trace element content of the human transitory milk collected on days 6 to 9 postpartum in Tokyo was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Ten elements (Na, Mg, P, S, K, Ca, Fe, Cu, Zn, and Sr) were detected in ten-fold diluted milk sample with this method. With the stepwise multiple regression analysis, maternal and infants' biological attributes, such as weight, stature, sex, or age, were noted as factors contributing to the interindividual variation in Na, Mg, P, S, and Sr. Biological mechanism responsible for this selection cannot be found. Days postpartum for the milk collection was selected as a highly significant (p less than 0.001) variable with negative coefficient to explain milk S variation.