LONGITUDINAL CHANGES OF TRACE-ELEMENTS IN HUMAN-MILK DURING THE 1ST 5 MONTHS OF LACTATION

Human milk samples were obtained from 6 women at various times during lactation for a total of 81 samples. Those from each woman were from 10 to 18 samples, sufficient to calcuate exponential regressions on an individual basis. Trace elements were measured using Inductively Coupled Argon Plasma Spectroscopy (ICAPS). Those elements in measurable quantities were zinc, silicon, copper, iron, barium, and strontium in the order found from the highest to the lowest concentrations. Means of 6 women ranged from 3.434 to 1.146 parts per million (ppm) for zinc, from 1.121 to.0570 ppm for silicon, .3800 to .1123 ppm for copper, from .3410 to .1733 ppm for iron, from .2833 to .0057 ppm for barium, and from .1057 to .0290 for strontium. Regressions for each element longitudinally on a daily basis showed concentrations of zinc, copper and iron being reduced significantly. In the cases of silicon, barium and strontium, longitudinal changes were not significant on a statistical basis. Fractional loss of zinc per day was -.01390 ; for copper it was -.00836; and the fractional loss of iron on a daily basis was -.01000. Other elements detected in some, but not all, samples included aluminum, lithium, manganese, and titanium. Manganese was measurable at the minimum detection limit of .007 ppm in only 6 of 81 milk samples. The mean for the 6 samples was .016 ppm.