Longitudinal zinc balances in breast-fed and formula-fed infants.
Longitudinal zinc (Zn) balance studies were performed under domestic conditions in term breast-fed (n = 10), term formula-fed (n = 5; Zn concentration in the formula: 4 mg/l) and preterm formula-fed (n = 3) infants during the first 17 weeks of life. Samples of milk, urine and feces were analyzed by atomic absorption spectrometry. The median daily Zn intake in breast-fed infants decreased from 0.592 (0.457-0.829) mg Zn/kg body weight to 0.151 (0.095-0.304) mg Zn/kg body weight in the first 17 weeks of life; comparable values for bottle-fed term infants were 0.58 (0.511-0.701) and 0.674 (0.529-0.731) mg Zn/kg body weight. The median percent retention of Zn intake was 27 (-60 to 81.4)% in breast-fed infants and 21.5 (-42 to 64)% in formula-fed infants. In view of the urinary and fecal Zn losses measured, a daily intake of 0.3-0.5 mg Zn/kg body weight is considered to be sufficient to ensure a Zn retention equivalent to breast-fed infants. This requires a Zn concentration of 2-3 mg/l of Zn depending on milk volume intake.
Sievers
E
E
Department of Paediatrics, Christian-Albrechts University, Kiel, Germany.
Oldigs
H D
HD
Dörner
K
K
Schaub
J
J
D001903:Bottle Feeding; D001942:Breast Feeding; D004032:Diet; D005260:Female; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D009751:Nutritional Requirements; D015032:Zinc / Q000008:administration & dosage / Q000172:deficiency / Q000378:metabolism*
D015032:Zinc