- On day 2, the mothers will be asked to breastfeed their infant from one breast for as long as the infant is interested. An electric breast pump will be placed simultaneously on the other breast for a Full Milk (FM) collection. For the duration of the study the same breast will be used for feeding the infant the other breast will be used for the FM collection. Three separate aliquots of fore milk (up to 1 minute), mid (50 mL), and hind (until the breast is empty) milk will be collected by a special funnel attached to the breast pump. A 5 mL aliquot of BM will be removed from each the 3 aliquots for creamatocrit measurement and later vitamin and mineral determinations. The remainder of the pumped breast milk will be pooled and given to the mother to feed to her infant. A fasting blood sample (7 mL) will be obtained by venipuncture to measure maternal MN status. A breakfast meal will be served to the mother after the first feeding and the blood draw. The mother will be asked to refrain from breastfeeding her infant for the next 2-3 hours then the collection procedure will be repeated until the mother goes to sleep at night, and at any time during the night that the mother wakes to feed her infant. The meals for breakfast, lunch and dinner will be low in micronutrients.