Klaus Dörner

Iron Availability from an Infant Formula Supplemented with Bovine Lactoferrin

ABSTRACT. Iron balance studies were performed in 16 term infants from their 3rd until their 17th week of life. The balance studies were performed at home and comprised five periods with an interval of 3 to 4 weeks, each consisting of three 24‐hour collections of milk and stool samples. Seven infants were fed an adapted infant formula supplemented with bovine lactoferrin (100 mg/100 ml) and nine received the same formula without lactoferrin. The lactoferrin supplemented group received 169 μg iron/kg b.w. × day and retained 63 μg/kg b.w. × day. The mean iron intake of infants fed with the adapted formula without supplementation of lactoferrin was 118 μg/kg b.w. × day. The retention of iron was 43 μg/kg b.w. × day. Mean percentage retention of iron in the supplemented group was 36%, in the non‐supplemented group 28%.

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/1 of Zn depending on milk volume intake.

Iron Balances in Infant Nutrition

ABSTRACT. Iron balance studies were performed in 17 full term male infants from their 3rd until their 17th week of life. The balance studies were made in the infants home and comprised 5 periods with an interval of 3–4 weeks, each consisting of three 24‐hour collections. Ten infants were breast‐fed, 3 received an adapted infant formula (P1, iron content 1.1 mg/l) and 4 were given the same formula enriched with iron, copper and zinc (P2, iron content 10.35 mg/l). From the 3rd to the 17th week of life the breast‐fed infants got a mean iron intake of 0.2 mg/kg body weight ×3 days and they retained 0.09 mg/kg b.w. ×3 days. The P1 group received 0.48 and 0.47 mg/kg b.w. ×3 days and retained ‐0.01 and ‐0.5 mg iron/kg b.w. ×3 days, while the P2 group had an intake from 5.04 to 6.38 mg b.w. ×3 days and retained between 1.13 and 3.66 mg iron/kg b.w. ×3 days. Comparing the 3 groups it can be concluded that the P1 group retained definitely less iron than the breast‐fed group, whereas the P2 group retained 12 to 40 times more iron than the breast‐fed babies.

Molybdenum metabolism: stable isotope studies in infancy.

The essential trace element molybdenum (Mo) is bound to and required for the function of molybdoenzymes, e.g. sulfite and xanthine oxidase. Dietary recommendations for early infancy are based on limited knowledge about its metabolism. 100Mo was used as an extrinsic tag to study the absorption and kinetics of excretion in infancy. 10 infants with a gestational age of 35 (30-39) weeks, a birth weight of 2.0 (0.9-2.3) kg and a post-natal age of 20 (10-54) days were studied. They received 25 microg 100Mo/kg with a feed of human milk or formula. Fractional urinary and fecal collections were conducted preceding the 100Mo intake and for 48-72 hours afterwards. The materials were analyzed by atomic absorption spectroscopy and inductively coupled plasma mass spectrometry. The median absorption of 100Mo intake was 97.5 (96.3 to 99.1) %. The retention of nutritive Mo intake and 100Mo in the study period was 11.2 (3.8-15.7) microg Mo/kg, equivalent to 35.7 (12.7-55.6) %. The Mo concentration increased to a peak value in urine within 8 (6-13) hours and in feces within 24 (7-48.5) hours. In addition, increases of copper in feces and urine were observed in 8 of 9 infants studied. Mo given orally is well resorbed in premature infants, and predominantly excreted in the urine. Dietary recommendations should prevent excessive intakes in infancy.

Molybdenum balance studies in premature male infants

Abstract Despite the fact that the trace element molybdenum (Mo) is essential, there is insufficient knowledge about the demands in infancy. Mo balances were therefore assessed under consideration of formula Mo concentrations ranging from 0.125 to 2.704 μmol/l. Sixteen premature male infants participated in the investigation. Their birth weights were between 1500 and 1990 g, the median (range) gestational age was 34 (32–36) weeks and the post-conceptual age at the time of study 37.4 (34.1–40.6) weeks. Twenty-four balance studies were performed and the materials analysed by atomic absorption spectroscopy. Infants with a “low” Mo intake received 0.024 (0.020–0.035) μmol/kg per day, had a urinary excretion of 0.02 (0.008–0.045) and a retention of 0.0006 (−0.03 to 0.008) μmol/kg per day. Infants with a “high” intake received 0.284 (0.227–0.487) μmol/kg per day, had a urinary excretion of 0.243 (0.118–0.378) and a retention of 0.022 (−71.1 to 141.44) μmol/kg per day. Since the median urinary excretion exceeded 60% of the Mo intake at low and high intakes, sufficient resorption but minimal retention was assessed at low intakes of Mo. Conclusion In view of the limited knowledge of long-term exposure to an elevated molybdenum intake and the substantial retention observed at higher intakes, upper limits should be set for molybdenum concentrations in preterm infant formulas.

Quantitative determination of lactose, maltose, and sucrose in urine

A simple method for determination of lactose, maltose and sucrose in urine is described. The principle of the method consists of enzymatic splitting of these disaccharides and specific measurement the resulting glucose by the Beckman Glucose-Analyzer. The precision and accuracy of the method have been evaluated and its clinical application is briefly discussed.

Trace element excess in PKU diets

SummaryKnowledge of trace element requirements of infants with phenylketonuria (PKU) fed a semisynthetic diet is limited. Three infants with PKU detected early were studied longitudinally in classical balance studies for 72 h, under domestic conditions, at the ages of 2, 5, 8, 12 and 16 weeks. Iron, copper and manganese concentrations in the diet and faeces were determined by atomic absorption spectroscopy. The median concentrations in the diet (4.8 mg Fe/L, 1.7 mg Cu/L, 0.43 mg Mn/L) exceed those in human milk. This is mainly due to supplementation of the amino acid preparation used. The increased intake led to a significantly higher daily retention of Cu and Mn from the PKU-diet fed, with a median of 0.17 mg Cu/kg and 6.4 µg Mn/kg body weight; the median retention of Fe was 0.24 mg Fe/kg. Our results confirmed the doubts about the suitability of the present trace element supplementation in formula for infants with PKU during the first four months of life.

58 TRACE ELEMENT OVERLOAD IN PKU - DIET|[quest]|

The knowledge of the trace element requirements of infants fed a phenylalanine restricted diet due to PKU ( Phenylketonuria ) is very limited. We studied 3 infants with PKU under their diet ( Milupa PKU 1 ) longitudinally in balance studies ( ≥ 72 hours ) under home conditions at the age of 2, 5, 8, 12, 16 weeks. Mn, Cu, Fe concentrations in diet, feces and urine were determined by Atomic Absorption Spectroscopy. Median concentrations found in the final diet were 1.7 mg/l Cu, 6 mg/l Fe, 0.5 mg/l Mn. The comparison of the retention rates with the data of 10 healthy breast-fed ( BF ) infants studied before ( s. table (showed a higher range of Mn and Fe retention.The median absolute retention of copper from PKU-diet exceeded that from human milk. Iron supplementation leading to median retentions sixfold the retentions from human milk seems to be unnecessary. Manganese supplementation should be avoided as neither symptoms of deficiency in formula-fed infants have been described nor possible side effects have been excluded.

Can Lactoferrin Supplementation Improve the Availability of Iron from Milk

The availability of iron from human milk is better than from cow milk or cow milk formulas. Lactoferrin, an important iron-binding protein in human milk has been considered responsible for the high bioavailability of breast-milk iron. To evaluate the possible role of lactoferrin on the availability of iron, we measured iron uptake from human milk and two cow-milk formulas; one of the latter was supplemented with bovine lactoferrin (100 mg/100 ml).

210 COPPER/MOLYBDENUM METABOLISM – INTERRELATIONSHIP IN PRETERM INFANTS?

Interferences of copper (Cu) and molybdenum (Mo) metabolism have been described (1). We evaluated in preterm infants 1.Cu balances under consideration of formula Mo content and 2. the course of the Cu concentration in feces and urine in stable isotope studies with 100Mo.1.) Intake, urinary and fecal excretion were collected over 72 hrs. in 14 male infants (gest. age: 32-37, 1.5-2.0 kg birth weight, 22 balances, formula: Prematil (Milupa AG, Germany)); Mo and Cu concentrations were determined by atomic absorption spectrometry :2.) In 10 preterm infants fecal and urinary specimens were collected over 48-72 hrs. after the intake of 25 μg/kg 100Mo added to formula. Within 14 hours urinary Mo increased 13(4-84)fold. For fecal Mo a 3.2(1.1-5.5)fold increase was observed in all but 2 infants within 24(6-26.25)hrs. Compared to the initial values, in 6/9 infants Cu concentrations increased up to 220(183-326)% in urine and 142(120-156)% in feces after the 100Mo intake. In the others, specimens preceeding the 100Mo intake rendered the highest Cu concentrations. Despite their considerable range the results suggest a potential influence of Mo intake on Cu excretion. (1)AmJClinNutr(1972); 25:1022-1037.