Human Milk-fed Infants Research Articles

The Source of Long-Chain PUFA in Formula Supplements Does Not Affect the Fatty Acid Composition of Plasma Lipids in Full-Term Infants

Supplementation of formulas for full-term infants with long-chain (LC) PUFA [arachidonic acid (AA) and docosahexaenoic acid (DHA)] at levels resembling human milk is recommended because they provide biochemical and functional benefits to the neonate. The objective of this work was to determine whether the source of dietary LC-PUFA affects the bioavailability in full-term infants. Treatment groups were as follows: full-term infants were fed from birth to 3 mo breast-milk (n = 11, 0.4 and 0.3 g/100 g total fatty acids as AA and DHA, respectively), formula containing LC-PUFA in the form of egg phospholipids (n = 12), or a formula supplemented with LC-PUFA in the form of triglycerides synthesized by single cells of algal and fungal microorganisms (n = 12). Both formulas provided 0.4 and 0.1 g/100 g total fatty acids as AA and DHA, respectively. We compared the fatty acid compositions of the main plasma lipid fractions (phospholipids, triglycerides, and cholesteryl esters) at birth and 3 mo. At 3 mo, lower levels of nervonic acid (NA), docosapentaenoic (DPA) acid, and DHA were found in all plasma lipid fractions from infants fed formula compared with those in the human milk-fed infants, irrespective of the source of the formula supplement (P < 0.02). These data demonstrate that the form of dietary LC-PUFA (triglycerides or phospholipids) does not influence their bioavailability. Similarly, absorption of LC-PUFA depends mainly on the lipid composition of the diet fed. These results suggest that the levels of NA, DPA, and DHA in formulas for full-term infants should be increased.

Nutrition Influences Bone Development from Infancy through Toddler Years

During the last decade a greater appreciation has developed for determining factors that influence bone accretion in healthy children. Nutritional factors that may contribute to bone accretion in infants and toddlers include maternal nutritional status during pregnancy, type of infant feeding, calcium and phosphorus content of infant formula, introduction of weaning foods, and diet during the toddler and preschool years. Maternal vitamin D deficiency during pregnancy is associated with disturbances in neonatal calcium homeostasis, and maternal calcium deficiency leads to reduced neonatal bone mineral content (BMC). Preterm infants are at increased risk of osteopenia, and, although the use of high mineral formula has reduced the risk of osteopenia in these infants, it has not eliminated it. The reason for the long-term bone deficiency among preterm infants is not clear, although lower physical activity levels have been suggested as a potential cause. Studies find that human milk-fed infants have lower bone accretion than do formula-fed infants; that the greater the mineral content of formula, the greater the bone accretion; and that the inclusion of palm olein oil in infant formula may reduce bone mineral accretion. Bone accretion is not influenced by the timing of the introduction of weaning foods, despite higher serum parathyroid hormone (PTH) concentrations among infants who receive solids earlier. There is evidence of calcium intake-by-gene and calcium intake-by-physical activity interactions among toddlers and young children. The long-term effects of these early nutritional influences on later bone health are unknown.

Inhibition of monocyte, lymphocyte, and neutrophil adhesion to endothelial cells by human milk oligosaccharides

Excessive leukocyte infiltration causes severe tissue damage in a variety of inflammatory diseases. The initial step in leukocyte extravasation is mediated by selectins and oligosaccharides on their glycoconjugate ligands. Human milk is a rich source of lactose-derived oligosaccharides that are partly absorbed in the intestine and excreted with the urine. As these components contain binding determinants for the selectins we investigated whether human milk oligosaccharides are able to affect leukocyte rolling and adhesion to endothelial cells under dynamic conditions. Therefore, monocytes, lymphocytes, or neutrophils isolated from human peripheral blood were passed over TNF-alpha-activated HUVEC under shear stress. The influence of different oligosaccharide fractions was determined by video-microscopy and compared with the effects of various individual oligosaccharides. Within a physiological range (12.5 - 125 microg/ml) the acidic fraction significantly inhibited leukocyte rolling and adhesion (up to 24.0% and 52.8%, respectively) in a concentration-dependent manner. These effects were even more pronounced than those achieved by soluble sialyl-Lewis x, a physiological binding determinant for selectins. Several active components within the oligosaccharide fraction of human milk were identified, e.g. 3'-sialyl-lactose and 3'-sialyl-3-fucosyl-lactose. These results indicate that specific oligosaccharides in human milk may serve as anti-inflammatory components and might therefore contribute to the lower incidence of inflammatory diseases in human milk-fed infants.

Factors affecting the introduction of complementary foods in the preterm infant.

The aim of the study was to identify current infant feeding practices among carers of preterm infants. Structured interviews on milk and complementary feeding practices were conducted with mothers of preterm infants at intervals until infants were 12 months corrected age. Recruitment took place in three local Surrey hospitals over a 2 y period. Two-hundred and fifty-three preterm infants (139 male, 114 female) including 33 sets of twins and three sets of triplets were recruited. Forty-nine percent of the preterm infant group received first solid foods (the commencement of 'weaning') before the current Department of Health (DoH) guideline. The mean+/-s.e.m. weaning age from birth was 17.1+/-0.23 weeks. Ninety-five percent of the infants were weaned before the DoH guideline when the data was examined from term (mean 11.5+/-s.e.m. 0.21 weeks). Twenty-one percent were weaned before the DoH guideline for preterm infants which is that 'the infant weighs at least 5 kg' (mean 5.61+/-s.e.m. 0.01 kg). Human milk-fed infants were significantly lighter at weaning than combined milk-fed infants (5.32+/-0.12 vs 5.72+/-0.01 kg; P<0.05) even though they were weaned at a similar age. Infant formula-fed infants (mean weaning age from term 10.2+/-0.47 weeks) were weaned significantly earlier than both human milk-fed (11.9+/-0.49 weeks; P<0.05) and combined milk-fed (11.9+/-0.25 weeks; P<0.005) infants. The introduction of complementary foods varied widely between carers of preterm infants and compliance with DoH guidelines was poor. Further studies on preterm infants are necessary to see if weaning practices affect long-term growth and morbidity and to provide a basis for the development of appropriate recommendations. This work was funded by the MAFF Food Intolerance Programme.

Achieving genetic potential for nutrition and growth in cystic fibrosis

Achieving genetic potential for nutrition and growth in cystic fibrosis

Polyunsaturated fatty acids and T-cell function: implications for the neonate.

Infant survival depends on the ability to respond effectively and appropriately to environmental challenges. Infants are born with a degree of immunological immaturity that renders them susceptible to infection and abnormal dietary responses (allergies). T-lymphocyte function is poorly developed at birth. The reduced ability of infants to respond to mitogens may be the result of the low number of CD45RO+ (memory/antigen-primed) T cells in the infant or the limited ability to produce cytokines [particularly interferon-y, interleukin (IL)-4, and IL-10. There have been many important changes in optimizing breast milk substitutes for infants; however, few have been directed at replacing factors in breast milk that convey immune benefits. Recent research has been directed at the neurological, retinal, and membrane benefits of adding 20:4n-6 (arachidonic acid; AA) and 22:6n-3 (docosahexaenoic acid; DHA) to infant formula. In adults and animals, feeding DHA affects T-cell function. However, the effect of these lipids on the development and function of the infant's immune system is not known. We recently reported the effect of adding DHA + AA to a standard infant formula on several functional indices of immune development. Compared with standard formula, feeding a formula containing DHA + AA increased the proportion of antigen mature (CD45RO+) CD4+ cells, improved IL-10 production, and reduced IL-2 production to levels not different from those of human milk-fed infants. This review will briefly describe T-cell development and the potential immune effect of feeding long-chain polyunsaturated fatty acids to the neonate.

The Use of Human Milk for Premature Infants

Various methods have been reported and used clinically to augment the nutrient supply for human milk-fed premature infants. These methods include specialized maltinutrient powdered mixtures (fortifiers), complete liquid formulas designed to be mixed with human milk, complete powdered formulas to be mixed with human milk, and alternate feeding of human milk and preterm formula. Although the optimum nutrition of premature infants is unknown, data are accumulating to suggest that human milk, fortified with additional nutrients, is appropriate for tube-fed infants. The use of fortified human milk typically provides premature infants adequate growth, nutrient retention, and biochemical indices of nutritional status when fed at approximately 180 mL/kg/d compared with unfortified human milk. Data are needed to determine the precise quantity of nutrients to be added as supplements. Nutrient interactions have not been explored in detail. Although large quantities of calcium seem to be needed, the exogenous calcium may affect fat absorption adversely. Manipulation of milk may affect the intrinsic host-defense properties of the milk. Compared with preterm formula, the feeding of fortified human milk may provide significant protection from infection and NEC. Lastly, the potential stimulation of an enteromammary pathway through skin-to-skin contact provides species-specific antimicrobial protection for premature infants. Several of these areas require additional exploration. Thus, for premature infants, neonatal centers should encourage the feeding of fortified human milk, together with skin-to-skin contact, as reasonable methods to enhance milk production while potentially facilitating the development of an enteromammary response.

Feeding tolerance in premature infants fed fortified human milk.

To evaluate feeding tolerance in premature infants immediately after the addition of human milk fortifier (HMF) to their expressed human milk diet. Data on milk intake, feeding tolerance, and related assessments and growth milestones from a prospective study of feeding strategies in premature infants were analyzed. The database was searched for the first day HMF was added to the feeding of infants receiving human milk exclusively. The following assessments were tabulated for the 5 days before and the 5 days after the addition of HMF: milk intake, the number of episodes of abdominal distension, gastric residual volume (GRV) more than 2 ml/kg and more than 50% of the volume fed in the prior 3 hours. bile-stained gastric residual, emesis or regurgitation, blood in the stool, the number of abdominal radiographs, the number of episodes of apnea and bradycardia, changes in findings in the clinical examination, and the number of hours feeding was withheld. The time to achieve full tube feeding, complete oral feeding, and hospital discharge were recorded. Seventy-six exclusively human milk-fed premature infants (birth weight, 1065+/-18 g; gestational age, 27+/-0.1 weeks; mean +/- SEM) who received HMF beginning 22+/-0.8 days of age were evaluated. There were significant increases in milk intake and in the number of episodes of GRV more than 2 ml/kg and emesis after the addition of HMF. There were no differences in the number of hours feeding was withheld or any other assessment after the addition of HMF. Infants with increases in GRV more than 2 ml/kg and/or emesis after the addition of HMF were not more likely to be delayed in the time to achieve full tube feeding, complete oral feeding, or hospital discharge than infants who did not experience these events. These data suggest that, when all feeding and related assessments and the time to achieve important growth milestones are considered, the addition of HMF does not adversely affect the outcome of the premature infant.

Growth in Human Milk-Fed Very Low Birth Weight Infants Receiving a New Human Milk Fortifier

Background/Aims: Human milk fortification has been advocated to enhance premature infants’ growth. We, therefore, undertook this study of a new human milk fortifier containing more protein than a reference one. Methods: Open, randomized, controlled, multiclinic trial, with weekly growth parameters and safety evaluations in premature infants <1,500 g. Results: The 2 groups did not differ in demographic and baseline characteristics. The adjusted daily milk intake was significantly higher in the infants fed reference human milk fortifier (n = 29; 154.2 ± 2.1 vs. 144.4 ± 2.5 ml/kg/day, mean ± SE; p < 0.05). Both human milk fortifiers produced increases over baseline in weight, length, and head circumference, with greater gains observed in the new human milk fortifier-fed infants for the former two parameters (weight gain 26.8 ± 1.3 and 20.4 ± 1.2 g/day, p < 0.05; head circumference 1.0 ± 0.1 and 0.8 ± 0.1 cm/week; length 0.9 ± 0.1 and 0.8 ± 0.1 cm/week, respectively). Serum chemistries were normal and acceptable for age. Study events were typical for premature infants and similar in both groups. Conclusions: This new human milk fortifier had comparable safety to the reference human milk fortifier and promoted faster weight gain and head circumference growth.

Essential fatty acids in early life: structural and functional role.

Essential fatty acids (EFA) are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LCPUFA). These fatty acids serve as specific precursors for eicosanoids that regulate numerous cell and organ functions. Results from animal and recent human studies support the essential nature of n-3 EFA in addition to the well-established role of n-6 EFA for human subjects, particularly in early life. The most significant effects relate to neural development and maturation of sensory systems. Recent studies using stable-isotope-labelled tracers demonstrate that even preterm infants are able to form arachidonic acid (AA) and docosahexaenoic acid (DHA), but that synthesis is extremely low. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation, and retinal and nervous system development. Regulation of gene expression by LCPUFA occurs at the transcriptional level and is mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the steroid hormone receptor family. Two types of polyunsaturated fatty acid responsive transcription factors have been characterized, the peroxisome proliferator-activated receptor (PPAR) and the hepatic nuclear factor 4alpha. DHA also has significant effects on photoreceptor membranes involved in the signal transduction process, rhodopsin activation, and rod and cone development. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oils, sources of LCPUFA, results in increased blood levels of DHA and AA, as well as an associated improvement in visual function in formula-fed premature infants to match that of human milk-fed infant. Recent clinical trials convincingly support LCPUFA supplementation of preterm infant formulations and possibly term formula to mimic human milk composition.

Secretion of 13C-Labelled Oligosaccharides into Human Milk and Infant's Urine after an Oral 13C-Galactose Load

Human milk oligosaccharides seem to play an important role in the infant's defense against bacterial and viral infections of the gastrointestinal and the urogenital tract. In this study, we investigated the influence of dietary carbohydrates on the biosynthesis of lactose and oligosaccharides in the human mammary gland and their renal excretion by the human milk-fed infant. For this purpose, a lactating woman was given 27 g galactose (Gal) containing 2 g [13C] Gal (1-13C/99%) immediately after breakfast. In the following 36 h. milk (5–10 ml) was collected before each nursing. Infant's urine was collected over a period of 24 h. 13C-enrichment was measured in total milk, milk fat and protein, in the carbohydrate fraction as well as in urine by isotope ratio mass spectrometry (IRMS). Milk carbohydrates and deproteinized urine samples were fractionated by Sephadex G25 gel nitration and further analyzed by IRMS, high performance thin layer chromatography and and high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). IRMS revealed that in milk a maximal δ13CPDB was reached within 8h after Gal intake which then rapidly declined in the following 8h. The cumulative 13C-elimination over this first peak was 6.9% of the oral 13C-dose. The highest 13C-enrichment was detectable in the carbohydrate fraction, mainly in lactose and neutral oligosaccharides. Compared to the enrichment of human milk, the δ13CPDB of infant's urine was delayed. In urine, the highest amount of 13C was found in the Sephadex G25 fractions which mainly contained lactose, fucosyl-lactose, lacto-N-tetraose (LNT), fucosyl-LNT and difucosyl-LNT. For further characterization, individual components were separated by HPAEC-PAD and subsequently analyzed by fast atom bombardment mass spectrometry and IRMS. The data show, that orally applied Gal is incorporated in milk, especially in lactose and neutral oligosaccharides. Obviously, some of these components were absorbed by the infant and then excreted with urine. There, oligosaccharides may serve as analogous receptors for bacterial or viral adhesion molecules, and, hence, may prevent urogenital infections in breastfed infants.

Utilization of supplemental iron by premature infants fed fortified human milk.

We measured red blood cell iron incorporation (RBC-inc) in 13 human milk-fed premature infants (birthweight 1037 +/- 289 g, gestational age 27 +/- 2 wk, weight at start of study 1571 +/- 426 g) who were receiving full tube-feedings of human milk fortified with a commercial human milk fortifier (FortHM). The relative RBC-inc of supplemental iron (2 mg/kg/d of ferrous sulfate) was assessed using 57Fe sulfate mixed directly into a 24-h volume of FortHM, and 54Fe sulfate given as a bolus between two FortHM feedings the next day. RBC-inc was similar between the two methods of supplemental iron administration (4.7 +/- 2.5% vs 4.6 +/- 1.5%, respectively). Although these values are lower than RBC-inc expected from iron native to human milk, the relatively large amount of iron in the supplements contributed most of the iron incorporated into RBC by the infants. There was a significant positive correlation between the reticulocyte count and RBC-inc. As the high nutrient (especially calcium) content of the FortHM did not interfere with iron utilization, adding iron directly to FortHM, or incorporating it into commercial fortifiers, may be a practical method to provide iron to premature infants.

Effects of nutrients in human milk on the recipient premature infant.

As the rate of survival of premature infants is increasing, more attention is necessarily focused on improving the quality of survival through optimal nutritional management. The nutritional needs of the premature infant are greater than at any other time in the life cycle. The benefits of human milk for term infants are well known. Emerging data suggest that human milk may especially benefit the premature infant. The human milk-fed premature infant may experience improved health (such as lower rates of infection and necrotizing enterocolitis), gastrointestinal function, and neurodevelopment. These factors may outweigh the concerns about adequate growth, nutrient accretion, and biochemical indices of nutritional status attributed to the lower nutrient content of human milk compared with preterm formula. Some of the nutritional concerns may be met by the use of multinutrient supplements during the time infants receive tube-feeding, generally the time prior to attaining complete oral feeding in-hospital. The available data suggest that the quality of survival of premature infants can be improved, both in the short-term and long-term, through the feeding of human milk.

Iron Absorption by Human Milk-fed Premature Infants Receiving Supplemental Iron ♦ 1551

To evaluate optimal methods of delivering iron (Fe) to human milk (HM)-fed preterm infants, we measured Fe utilization by 8 HM-fed premature infants[birth weight 1.0 (0.2) kg, gestational age 27 (2) wk, weight at start of study 1.4 (0.3) kg] who were receiving full feedings of human milk fortified with a commercial human milk fortifier. Supplemental Fe was given daily for 7-14 days before the study as 2 mg/kg of ferrous sulfate administered between feedings. On the first study day, 57Fe (2 mg/kg) which had been premixed with a 24-hour supply of fortified HM was fed to the infants, and 58Fe (70 mcg) was administered intravenously (IV). On study day 2, no Fe was mixed with the HM, but 54Fe (2 mg/kg) was administered as ferrous sulfate by orogastric gavage between feedings. Two weeks later, a 1-mL blood sample was collected and red blood cell incorporation (RBC-inc) was calculated from measurement of the isotope enrichment performed using magnetic sector thermal ionization mass spectrometry. Percent absorption was calculated by dividing the RBC-inc of 54Fe and 57Fe by the RBC-inc of 58Fe. All data are mean (SD).

Acid steatocrit during infancy.

The faecal acid steatocrit is an improved steatocrit method for the evaluation of faecal fat. The present study was set up in order to establish reference values during the first year of life. Faecal acid steatocrit values were determined in 58 healthy full term and in 16 healthy prematurely born infants. Very high acid steatocrit results (above 60%) were found in all premature and many formula-fed term infants during the first 6 months of age, thereafter with values below 10%. In 40- to 120-day-old infants acid steatocrit results of human milk-fed infants were significantly lower than those of formula-fed infants (p < 0.01). We conclude that high acid steatocrit results after the age of 6 months are indicative of fat malabsorption, while before this age high values can be due to "physiological steatorrhoea". The acid steatocrit should be useful for the evaluation of milk fat absorption in infants.

Urinary oxalate excretion in premature infants: effect of human milk versus formula feeding

To study urinary oxalate excretion in infants fed human milk versus formula, and to compare urinary calcium oxalate and calcium phosphate saturation in premature infants with term infants and adults. We measured urinary oxalate-to-creatinine ratio and urinary oxalate concentration in 15 premature infants fed human milk compared to 16 formula-fed premature infants, and in eight human milk-fed term infants compared to 17 formula-fed term infants. We then studied urinary calcium oxalate and calcium phosphate saturations based on our observations of elevated urinary oxalate excretion in premature infants. Urinary calcium oxalate and calcium phosphate saturations were calculated from urinary concentrations of oxalate, calcium, sodium, potassium, chloride, uric acid, magnesium, phosphorus, and urinary pH. We calculated urinary calcium oxalate and calcium phosphate saturations in nine healthy adults and nine formula-fed term infants to establish control values for urinary saturation. Urinary calcium oxalate and calcium phosphate saturations were determined in nine premature infants receiving a glucose and electrolyte solution, 11 premature infants receiving parenteral nutrition, nine formula-fed premature infants, and 11 human milk-fed premature infants. Urinary oxalate excretion was higher in formula-fed compared to human milk-fed premature infants whether expressed as oxalate-to-creatinine ratio (0.32 +/- 0.04 versus 0.18 +/- 0.03, P < .01) or urinary oxalate concentration (0.047 +/- 0.007 versus 0.022 +/- 0.002 mg/mL, P < .01). Urinary oxalate excretion was higher in formula-fed term infants than in human milk-fed term infants whether expressed as oxalate-to-creatinine ratio (0.14 +/- 0.01 versus 0.07 +/- 0.01, P < .01) or urinary oxalate concentration (0.022 +/- 0.002 versus 0.012 +/- 0.002 mg/mL, P < .01). The urinary calcium oxalate saturation in healthy adults was 2.84 +/- 0.79; the value in formula-fed term infants was 2.12 +/- 0.31. The urinary calcium oxalate saturation was significantly higher in premature infants receiving formula (15.68 +/- 3.15), human milk (15.02 +/- 2.27), or parenteral nutrition (11.38 +/- 2.56) compared to adults or term infants (P < .01). Urinary calcium oxalate saturation in premature infants receiving a glucose and electrolyte solution (2.45 +/- 0.36) was not significantly different from that in adults or term infants. In contrast, urinary calcium phosphate saturation in premature infants as well as term infants and adults was less than 1; precipitation of calcium phosphate is not likely to occur under these conditions. Formula-fed infants have higher urinary oxalate excretion than human milk-fed infants. Premature infants receiving standard nutritional regimens may have urinary calcium oxalate saturation levels at which dissolved calcium oxalate may form nuclei of its solid phase.

Fatty acid composition of plasma and red blood cell phospholipids in preterm infants from 2 weeks to 6 months postpartum.

The purpose of this study was to follow the long-chain polyunsaturated fatty acid (LCP) status in initially human milk-fed preterm infants from 2 weeks to 6 months postpartum. Twenty-two infants aged 27-33 weeks of gestation at birth who had a birthweight of 710-2525 g were fed human milk for > or = 4 weeks. After discharge from the hospital, they were either human milk-fed or formula-fed according to their mothers' decision: 10 were fully breast-fed for 6 months and 12 were formula-fed after discharge at 1-2 months. The formula fat contained 20% 18:2n-6 and 3% 18:3n-3 but was devoid of long-chain polyunsaturated fatty acids (LCP). Blood samples were taken at 2 weeks, 3 months, and 6 months postpartum. Percentage fatty acid compositions in red blood cell (RBC) and plasma total phospholipids were analyzed by capillary gas liquid chromatography. In formula-fed infants, the change from human milk to formula resulted in a significant rise in plasma and RBC 18:2n-6 and 18:3n-3 and a decrease in plasma 20:4n-6. Interestingly, RBC 20:4n-6 remained constant in both groups, even after 4-5 months of formula feeding. In the formula-fed group, RBC 22:5n-6 showed an increasing trend. The largest changes were seen in 22:6n-3; in the formula-fed group, it decreased in both plasma and RBC, whereas in the human milk-fed group, it showed an increasing trend.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium, phosphorus and magnesium needs for the low‐birth‐weighi infant

Parental mineral-containing solutions for LBW infants should be started soon after birth. For the initiation of parenteral nutrition and during short-term therapy for less than 2 weeks' duration, LBW infants should receive parenteral nutrition solutions at rates of approximately 120-130 ml/kg/day, containing minerals at the following concentrations: Ca 15 mM, P 15 mM and Mg 2.5 mM. For optimal growth and nutrient utilization, however, LBW infants maintained on parenteral nutrition at rates of 120-130 ml/kg/day for 2 or more weeks should receive mineral concentrations of Ca 20 mM, P 20 mM and Mg 2.5 mM. In addition, these latter mixtures must contain amino acids in concentrations greater than or equal to 2.2 g% and cysteine-HCl must be provided. As newer formulations emerge, these recommendations may be modified. For human milk-fed LBW infants, after 1 week of enteral feeding, Ca and P should be supplied as fortifiers. Ca 2-3 mmol/kg/day and P 1.5-2.0 mmol/kg/day should be provided in addition to human milk. Magnesium supplementation of human milk is unnecessary. These recommendations assume that the intake of human milk is approximately 200 ml/kg/day and will decrease as more bioavailable mineral salts are found. For LBW infants fed commercial formula, the intake of Ca should be greater than 3.5 mmol/kg/day, P 2.5 mmol/kg/day and Mg 0.2 mmol/kg/day. These recommendations assume reported bioavailabilities of mineral salts. If more bioavailable sources are found, these recommendations will decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary Oxalate Excretion in Premature Infants: Effect of Human Milk Versus Formula Feeding

Objective. To study urinary oxalate excretion in infants fed human milk versus formula, and to compare urinary calcium oxalate and calcium phosphate saturation in premature infants with term infants and adults. Methodology. We measured urinary oxalate-to-creatinine ratio and urinary oxalate concentration in 15 premature infants fed human milk compared to 16 formula-fed premature infants, and in eight human milk-fed term infants compared to 17 formula-fed term infants. We then studied urinary calcium oxalate and calcium phosphate saturations based on our observations of elevated urinary oxalate excretion in premature infants. Urinary calcium oxalate and calcium phosphate saturations were calculated from urinary concentrations of oxalate, calcium, sodium, potassium, chloride, uric acid, magnesium, phosphorus, and urinary pH. We calculated urinary calcium oxalate and calcium phosphate saturations in nine healthy adults and nine formula-fed term infants to establish control values for urinary saturation. Urinary calcium oxalate and calcium phosphate saturations were determined in nine premature infants receiving a glucose and electrolyte solution, 11 premature infants receiving parenteral nutrition, nine formula-fed premature infants, and 11 human milk-fed premature infants. Results. Urinary oxalate excretion was higher in formula-fed compared to human milk-fed premature infants whether expressed as oxalate-to-creatinine ratio (0.32 ± 0.04 versus 0.18 ± 0.03, P &amp;lt; .01) or urinary oxalate concentration (0.047 ± 0.007 versus 0.022 ± 0.002 mg/mL, P &amp;lt; .01). Urinary oxalate excretion was higher in formula-fed term infants than in human milk-fed term infants whether expressed as oxalate-to-creatinine ratio (0.14 ± 0.01 versus 0.07 ± 0.01, P &amp;lt; .01) or urinary oxalate concentration (0.022 ± 0.002 versus 0.012 ± 0.002 mg/mL, P &amp;lt; .01). The urinary calcium oxalate saturation in healthy adults was 2.84 ± 0.79; the value in formula-fed term infants was 2.12 ± 0.31. The urinary calcium oxalate saturation was significantly higher in premature infants receiving formula (15.68 ± 3.15), human milk (15.02 ± 2.27), or parenteral nutrition (11.38 ± 2.56) compared to adults or term infants (P &amp;lt; .01). Urinary calcium oxalate saturation in premature infants receiving a glucose and electrolyte solution (2.45 ± 0.36) was not significantly different from that in adults or term infants. In contrast, urinary calcium phosphate saturation in premature infants as well as term infants and adults was less than 1; precipitation of calcium phosphate is not likely to occur under these conditions. Conclusion. Formula-fed infants have higher urinary oxalate excretion than human milk-fed infants. Premature infants receiving standard nutritional regimens may have urinary calcium oxalate saturation levels at which dissolved calcium oxalate may form nuclei of its solid phase.

Effects of human milk or formula feeding on the growth, behavior, and protein status of preterm infants discharged from the newborn intensive care unit

The growth, behavior, and protein status of 59 healthy preterm (mean gestational age 30 wk) infants fed either human milk or one of three infant formulas were studied post-discharge from the hospital. Formula-fed infants received either a standard term formula, a standard preterm formula, or an experimental preterm formula from discharge to 8 wk of age. From 8 to 16 wk, all formula-fed infants received the standard term formula. At 2, 8, and 16 wk, anthropometric, dietary intake, blood biochemistry, amino acid, and Brazelton Neonatal Behavioral Assessment measurements were evaluated. Weights, lengths, and head circumferences were similar for all feeding groups at discharge. After discharge all formula-fed infants were heavier than human milk-fed infants. Length and head circumference values and plasma urea nitrogen and retinol-binding protein concentrations were not different among dietary groups. Formula-fed infants had higher plasma concentrations of numerous amino acids compared with those of human milk-fed infants during the first 8 wk but not at 16 wk. There were no differences among the feeding groups in the Brazelton assessment. This study found little effect on the growth or behavioral or protein status of preterm infants discharged from the hospital who were fed either human milk or formulas designed for term or preterm infants.