Elemental composition of human milk from mothers of premature and full-term infants during the first 3 months of lactation

To examine longitudinal and gestational effects of mineral content in human milk, we analyzed human milk from lactating mothers of premature (PRT, n = 24, < 2000 g birth weight, < 37 wk gestation) and full-term (FT, n = 19, > 2500 g, 39-41 wk gestation), living in Newfoundland, Canada. Samples were collected once a week for 8 wk with one final sample collected at 3 mo. Mil k samples collected in acid-washed containers were wet ashed with concentra ted HNO3, and barium, cadmium, calcium, cesium, cobalt, copper, cerium, lan thanum, magnesium, manganese, molybdenum, nickel, lead, rubidium, tin, stro ntium, and zinc were measured using inductively coupled plasma-mass spectro metry. Data were analyzed using standard multiple-regression procedures wit h correlated data analyses to take account of the relationship between succ essive weeks. Results indicated lower Ca and Pb in PRT milk. Calcium was th e only nutritionally significant element to differ between groups. Molybden um in both PRT and FT milk showed a definite decrease with time, suggesting that the Mo content in milk is homeostatically regulated. However, Ce, La, Ba, and Sn did not display any pattern indicative of biological regulation and potential human requirement.