Growth and metabolic responses in low-birth-weight infants fed human milk fortified with human milk protein or with a bovine milk protein preparation

Unfortified human milk does not normally provide enough protein to secure maximal growth in low-body-weight (LBW) infants. Due to the practical difficulties in obtaining human milk protein (HMP), a bovine milk protein preparation (BMP) was designed by computer calculation to contain as close as possible the amino acid composition of the nutritionally available human milk proteins. Twenty-one AGA, LBW infants (BW of 1,180 to 1,600 g, GA of 27 to 33 weeks) were randomly assigned to be fed HM enriched either with HMP (9 infants) or BMP (12 infants). When full volume intake (170 ml/kg/day) was reached, the protein intakes were 3.6 +/- 0.5 and 3.3 +/- 0.3 g/kg/day, respectively, in the two diet groups. During the study period of 24 days, the infants achieved intrauterine or better weight gains: 32.9 +/- 3.3 g/day (17.7 +/- 1.9 g/kg/day) in the HMP group and 34.7 +/- 7.3 g/day (18.3 +/- 3.5 g/kg/day) in the BMP group. Serum urea nitrogen, acid-base status, and albumin values were normal and similar in both groups of infants. Plasma concentrations of total essential and total amino acids at the end of the study were 3,999 and 1,539 mumol/L and 3,899 and 1,422 mumol/L in the HMP and the BMP groups, respectively. The concentrations of all individual plasma amino acids were similar in both feeding groups. These results show that feeding human milk fortified with a modified bovine milk protein preparation produces satisfactory growth and a plasma amino acid profile similar to that found in LBW infants fed exclusively human milk protein at similar intakes.     

Alterations of serum bile acid profile in breast-fed infants with prolonged jaundice

Serum bile acid conjugates in breast-fed infants with prolonged jaundice were analyzed by a newly developed procedure using high-performance liquid chromatography with fluorescence labeling. Major bile acids were cholate and chenodeoxycholate conjugates. Some of the breast-fed jaundiced infants had high levels of serum bile acid conjugates (greater than 25 mumol/L), but the mean levels of individual bile acid conjugates found in jaundiced breastfed infants were not significantly different from those in breast-fed infants without jaundice. The glycine- to taurine-conjugated bile acid ratio in breast-fed jaundiced infants was significantly lower than in breast-fed nonjaundiced infants or bottle-fed nonjaundiced infants. In breast-fed infants, the portion of taurine-conjugated bile acids increased in proportion to serum bilirubin levels. These findings suggest that alteration in conjugated bile acid patterns of breast milk jaundice is related to an increased enterohepatic circulation of bile acids as well as bilirubin in infants fed on breast milk that contains high amounts of taurine.     

The effect of food supplements on the bioavailability of breast milk for premature infants--fecal fat and carbohydrate excretion

Faecal excretion of fat and carbohydrates was studied in 14 preterm infants fed on raw mother's milk (group I) or banked fortified human milk (group II) at days 7, 14, 21 and 28 of postnatal life: group I: n = 5; 31.0 +/- 2.0 weeks; 1954 +/- 441 g; group II: n = 9; 32.0 +/- 1.0 weeks; 1806 +/- 176 g. Mixtures of amino acids, peptides, minerals, dextrine and maltose were designed for fortifying banked human milk. There were no significant differences between faecal excretion of fat and carbohydrates in both feeding groups. The investigated human milk fortifier helps to realize the protein-energy ratio needed in preterm infants with well tolerable volumes of feeding and without stressing their limited digestive capacity.     

Fatty acid balance studies in preterm infants fed formula milk containing long-chain polyunsaturated fatty acids (LCP) II

A milk formula (Prematil-LCP) containing long-chain polyunsaturated fatty acids (LCP) and with a fatty acid profile closely resembling breast milk has recently been introduced for preterm infants. A double-blind randomized controlled trial was performed comparing fatty acid absorption from Prematil-LCP (n = 10) and standard Prematil (n = 10). Formula-fed preterm infants underwent 3 d fat balances (once full enteral feeds were established) along with a parallel human milk fed group (n = 11). Plasma samples were taken on the last day. Median total fat excretion (absorption, %) was 2.34 g kg (82.0), 2.64 g kg (82.9) and 1.65 g kg (87.8) with Prematil, Prematil-LCP and human milk feeding, respectively. This reflected differences in the excretion and absorption of long-chain saturated fatty acids. All groups excreted detectable LCP. LCP disappearance was higher in infants fed human milk than in those fed Prematil-LCP, particularly for n -6 LCP (p <0:01). Nevertheless, excreted LCP equated to <30% dietary intake, with Prematil-LCP feeding. Plasma lipid fatty acid composition reflected differences in dietary LCP intake.     

Sulfated and nonsulfated bile acids in urine of patients with biliary atresia: analysis of bile acids by high-performance liquid chromatography

To elucidate urinary bile acid patterns in patients with biliary atresia (BA), 15 sulfated and nonsulfated bile acids in urine were separately measured by high-performance liquid chromatography. This relatively simple technique for fluorescence detection utilizes the enzyme 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) to reveal urinary bile acid patterns. By this method, recovery rates of sulfated and nonsulfated bile acids in urine were satisfactory, and this analysis was shown to be applicable to clinical situations. In 10 patients with BA, the mean level of total bile acids in urine (23.35 +/- 18.51 mumol/day) was seven times higher than the mean level in eight normal infants (3.05 +/- 2.05 mumol/day). In the infants with BA, the mean level of total sulfated bile acids was about half of the total bile acid level. The main components of urinary nonsulfated bile acids in BA were glycocholic acid (6.21 +/- 5.55 mumol/day) and taurocholic acid (2.28 +/- 1.33 mumol/day), whereas the main components of the urinary sulfated bile acids were glycochenodeoxycholic acid (4.58 +/- 6.97 mumol/day) and taurochenodeoxycholic acid (3.67 +/- 3.54 mumol/day). Chenodeoxycholic acid, which is relatively toxic to the liver, may more easily be conjugated with sulfate and, hence, excreted into urine at a faster rate than cholic acid. Marked individual variations in urinary bile acid patterns were observed not only in BA patients but also in normal controls.     

Growth and biochemical response of premature infants fed pooled preterm milk or special formula

This study compared growth of a group of very low birth weight infants fed a formula specifically developed for such infants (Formula) with another group fed expressed breast milk (EBM). The Formula contained 2.4 g/dl of protein (lactalbumin:casein ratio, 60:40); 4.1 g/dl of fat (40% medium-chain triglycerides); 8.8 g/dl of carbohydrates; and 81 kcal/dl, with more calcium, phosphorus, and electrolytes than are in human milk. Premature babies with birth weights between 1,200 and 1,500 g and gestational age less than 36 weeks were eligible for the study and were fed either pooled EBM or Formula until they reached a weight of 1,800 g. Twenty infants fed EBM and 19 infants fed Formula completed the trial. Weight gain was faster in the Formula-fed infants after a caloric intake of 100 kcal/kg/day was achieved (Formula 27.7 g/day vs. EBM 17.2 g/day; p less than 0.001). Time to reach 1,800 g was 27 days for the Formula group and 39 days for those on EBM (p less than 0.001). Increments in head circumference and skinfold thickness were also greater in the Formula-fed group. Laboratory studies in the two groups of infants showed higher alkaline phosphatase levels, which were not due to vitamin D deficiency, in the EBM-fed infants.     

Protein supplementation of human milk for the nutrition of VLBW-infants: human milk protein vs. meat protein hydrolysate

In 25 very low birth weight infants appropriate for gestational age the influences of different human milk (HM) preparations on weight gain, gross indices of nitrogen metabolism and energy balance were studied during the second month of postnatal life. HM was fortified either by HM-protein (HMP) or by an enzymatic meat protein hydrolysate (PH) to protein concentrations between 1.5 and 1.7 g/100 ml. The caloric densities of both HM preparations were similar between 62 and 68 kcal/100 ml. There were no differences in weight gain (MM + HMP: 18.6 +/- 3.4 g/kg/day; HM + PH: 16.5 +/- 4.1 g/kg/day), nitrogen retention (HM + HMP: 31.5 +/- 3.1 mmol/kg/day; HM + PH: 30.0 +/- 3.2 mmol/kg/day), and the preprandial estimated essential amino acid profiles between the both feeding groups. In contrast the serum concentrations of alpha-amino-nitrogen 60 minutes postprandially were elevated in the infants fed HM + PH in comparison to the infants fed HM + HMP. This high postprandial amino acid concentrations in serum in the group fed HM + PH were accompanied by increased bile acids concentrations in serum, higher renal amino acid excretion and increased fecal fat losses. The results suggest that due to the more rapid intestinal absorption of amino acids from PH than from HMP the concentrations of amino acids increase postprandially which results in a detectable increase of the newborn cholestasis in these infants. Nevertheless, the scale of these metabolic responses to feeding protein hydrolysates is small and without detectable influences on nitrogen retention or weight gain.     

Effects of calcium and phosphorus supplementation on calcium retention and fat absorption in preterm infants fed pooled human milk

Fat, phosphorus, and calcium balance studies were performed in normal very low birth weight infants (BW less than or equal to 1,500 g) fed either normal or calcium- and phosphorus-supplemented pooled pasteurized human milk. Calcium and phosphorus supplements were 27 mg/dl and 24.5 mg/dl, respectively, throughout the study. Measured calcium and phosphorus intake in the supplemented group averaged 90 +/- 6 mg/kg/day and 62 mg/kg/day, respectively, compared to 47 +/- 7 mg/kg/day and 24 +/- 6 mg/kg/day in the nonsupplemented group. The percent of fat, calcium, and phosphorus absorption was similar in the two groups: respectively, 71 +/- 23%, 73 +/- 13%, and 93 +/- 2% in the supplemented group compared to 75 +/- 11%, 71 +/- 14%, and 92 +/- 4% in the nonsupplemented group. Calcium and phosphorus retention reached 62 +/- 12 mg/kg/day and 53 +/- 4 mg/kg/day in the supplemented group against 21 +/- 10 mg/kg/day and 21 +/- 5 mg/kg/day in the nonsupplemented group. These data support the notion that calcium, in addition to phosphorus supplementation in pooled human breast milk, improves both calcium and phosphorus retention in preterm infants.     

Influence of dietary taurine on vitamin D absorption

To evaluate the influence of dietary taurine supplementation on vitamin D absorption, we studied three groups of infants: 21 (11 preterm) were fed a taurine-free formula, 21 (10 preterm) were fed a taurine-supplemented formula (50 mg/100 g of powder) and 20 (9 preterm) were fed human, not heat-treated milk. Taurine, total bile acids, glyco-(GBA) and tauro-(TBA) conjugated bile acids, 25–hydroxyvita-min D3 (250HD3) and 1,25–dihydroxyvitamin D3 (1,250H2D3) were determined in all infants at birth in blood cord and at one and three months of life. In preterm infants fed a taurine-free formula, we found lower plasma taurine levels than in infants of other groups at one and three months of life. In these infants, GBA predominated, with a G/T ratio of 1.1 and 1.4 at one and three months of life, whereas in all other infants TBA predominated with a G/T ratio always < 1. Also, 250HD3 and 1,250H2D3 levels were significantly lower in preterm infants fed a taurine-free formula than in infants fed a taurine-enriched formula or human milk. Term infants fed a taurine-free formula did not show differences in the parameters studied in comparison to infants of other groups. Low taurine dietary intake appears to compromise vitamin D absorption in preterm infants, and therefore taurine supplementation of preterm infant formulas should be encouraged.     

Studies on the conjugating activity of bile acids in children

The unconjugated and conjugated bile acid levels in sera of 98 normal children and nine normal adults were measured by high performance liquid chromatography. The results showed that the mean total bile acid level was high, 11.0 +/- 8.7 mumol/liter (1 SD) during the neonatal period (0-4 wk) and then gradually decreased with age. The ratio of the concentration of conjugated bile acids to total bile acids in serum was as high as 90% or more in infants under 1 yr of age and slowly decreased with age. The mean ratio of cholic acid to chenodeoxycholic acid was high (1.7 +/- 1.1) during the neonatal period but decreased after 3 months to the adult level (0.4 +/- 0.2). The mean ratio of glycine conjugated bile acids to taurine conjugated bile acids was 3.0 +/- 3.1 during the neonatal period and the ratio during the 1st month of life was significantly lower than that after that period with little further change at any age. The mean ratio of the concentration of secondary bile acids to primary bile acids showed significantly lower values in infants less than 1 yr of age. The main bile acid was glycocholic acid in the neonatal period but after 1-3 months glycochenodeoxycholic acid predominated. With age, the serum bile acid pattern which was characteristic in infancy gradually approached that of adults.     

Influence of dietary taurine on vitamin D absorption

To evaluate the influence of dietary taurine supplementation on vitamin D absorption, we studied three groups of infants: 21 (11 preterm) were fed a taurine-free formula, 21 (10 preterm) were fed a taurine-supplemented formula (50 mg/100 g of powder) and 20 (9 preterm) were fed human, not heat-treated milk. Taurine, total bile acids, glyco-(GBA) and tauro-(TBA) conjugated bile acids, 25–hydroxyvita-min D3 (250HD3) and 1,25–dihydroxyvitamin D3 (1,250H2D3) were determined in all infants at birth in blood cord and at one and three months of life. In preterm infants fed a taurine-free formula, we found lower plasma taurine levels than in infants of other groups at one and three months of life. In these infants, GBA predominated, with a G/T ratio of 1.1 and 1.4 at one and three months of life, whereas in all other infants TBA predominated with a G/T ratio always < I. Also, 250HD3 and 1,250H2D3 levels were significantly lower in preterm infants fed a taurine-free formula than in infants fed a taurine-enriched formula or human milk. Term infants fed a taurine-free formula did not show differences in the parameters studied in comparison to infants of other groups. Low taurine dietary intake appears to compromise vitamin D absorption in preterm infants, and therefore taurine supplementation of preterm infant formulas should be encouraged.     

Nutritional balance studies of VLBW infants fed their mothers' milk fortified with a liquid human milk fortifier

This article reports the results of a study designed to compare human milk fortified with a liquid human milk fortifier to a preterm infant formula by analyzing the metabolic balances of certain nutrients when these milks are fed to premature infants. Ten very low birth weight (VLBW) infants were studied during 4-day equilibration periods, then 4-day metabolic balances of N, fat, Ca and P, while each consumed a 1:1 mixture of a pool of its own mother's milk and the liquid human milk fortifier (HM/LF). For comparison, another 10 VLBW infants were studied in similar fashion while consuming the preterm infant formula (PF). Percent nitrogen retentions were 77 +/- 4% (+SD) and 79 +/- 4%, and fat absorptions were 94 +/- 7% and 92 +/- 5% in the HM/LF and PF groups, respectively, and did not differ between the groups. Calcium retention was 86 +/- 21 mg/kg/day (51 +/- 12%) in the HM/LF group and 104 +/- 43 mg/kg/day (45 +/- 19%) in the PF group. The percent Ca retentions did not differ. Phosphorus retentions were 56 +/- 7 mg/kg/day (67 +/- 9%) and 77 +/- 18 mg/kg/day (61 +/- 14%) in the HM/LF and PF groups, respectively. Increases in weight, length, and occipitofrontal circumference (OFC) were similar and normal in both groups. We conclude that VLBW infants fed the HM/LF, mixed 1:1 with their mothers' milk, had rates of absorption and retention of Ca, P, N, and fat similar to rates found in the concurrent study of VLBW infants fed a commercially available PF.     

Enterohepatic circulation of nonconjugated bilirubin in rats fed with human milk

To test the hypothesis that enhanced intestinal absorption of bilirubin may contribute to prolonged nonconjugated hyperbilirubinemia in human milk-fed infants, we studied a cross-section of 36 healthy infants and mothers. Milk from mothers and serum from infants were collected at 16.3 +/- 2.4 days. Milk was studied for its effect on the absorption of bilirubin labeled with carbon 14 in rats and compared with buffer and iron-fortified infant formula (Similac With Iron). The percentage of a 1 mg bilirubin dose absorbed by the rat was 25.29 +/- 4.0% when it was administered into the duodenum with buffer, 4.67 +/- 2.4% with Similac formula, and 7.7 +/- 2.9% with human milk. Linear regression analysis, using the infant's serum nonconjugated bilirubin level as the dependent variable and the percentage of (14C)bilirubin absorbed by the rat with the corresponding mother's milk as the independent variable, revealed a significant correlation (r = 0.40; p = 0.016). Inspection of the data suggested that absorptive permissiveness correlated closely with infant serum bilirubin values greater than 24 mumol/L (1.4 mg/dl) (r = 0.55; p = 0.007), whereas in those with bilirubin values less than or equal to 24 mumol/L, there was no apparent correlation. Milk was also analyzed for beta-glucuronidase, nonesterified fatty acids, and the ability to inhibit glucuronosyltransferase activity of rat liver microsomes in vitro, none of which correlated with the infant's serum bilirubin. These data support the theory that enhanced intestinal absorption of bilirubin contributes to the jaundice associated with breast-feeding.     

Fat absorption in preterm infants fed a taurine-enriched formula

An adapted cow's milk infant formula without or with extra taurine (350 μmol/l) was fed to four and five infants, respectively. The infants, born after 28–32 weeks gestation, and initially fed with a starting formula for preterms, were switched to one of the two above-mentioned formulae at approximately the 16th day of life. Each infant was studied during 4 consecutive weeks. The faecal excretion of fat, energy and total bile acids was determined from 3-day stool collections each week. The addition of taurine to the infant formula neither improved the uptake of fat and energy nor changed the faecal bile acid excretion. Growth velocity was similar in both groups of infants. Based on these results there is no rationale for adding taurine to adapted cow's milk infant formula to obtain a better fat absorption.     

Neonatal nutrition with enriched human milk. EOPROTIN 60 in comparison with human albumin]

The influence of feeding fresh human milk supplemented either with EOPROTIN (n = 13) or human albumin (n = 15) on biochemical parameters and growth were studied in preterm infants with gestational ages below 32 weeks p.m. up to the 42nd day of postnatal life. In both feeding groups the intakes of protein, energy and electrolytes were similar. The serum concentrations of bile acids, alpha-amino-nitrogen and prealbumin, the renal excretion of total nitrogen, alpha-amino-nitrogen, urea and ammonia as well as the growth in weight and length were studied in all infants. The supplementation of the fresh human milk with EOPROTIN results in significant lower serum concentrations of alpha-amino-nitrogen (1.56 +/- 0.21 vs 2.03 +/- 0.27 mmol/l; p less than 0.01), higher serum concentrations of prealbumin (89.8 +/- 20.3 vs 72.7 +/- 13.3 mg/l; p less than 0.02), and lower urinary excretion of total nitrogen (7.4 +/- 0.9 vs 8.9 +/- 1.1 mmol/kg/day); if compared to the results found in the infants fed human albumin supplemented human milk. The higher nitrogen retention in the EOPROTIN than in the human albumin fed infants was associated by a significant higher growth in weight (16.6 +/- 1.4 vs 13.7 +/- 1.9 g/kg/day; p less than 0.01) as well as in length (1.02 +/- 0.08 vs 0.87 +/- 0.1 cm/week; p less than 0.01). The results indicate that the bioavailability of EOPROTIN is higher than that of human albumin. The observed differences in the nutritional response between the two human milk supplements may be based on differences in the amino acids composition which is in EOPROTIN adapted to the nutritional available part of the protein in human milk.     

Taurine depletion in very low birth weight infants receiving prolonged total parenteral nutrition: role of renal immaturity

In a prospective, controlled study, plasma and urinary taurine concentrations were determined weekly, between postnatal weeks 3 and 18, in (1) seven sick infants (gestational age less than 28 weeks, birth weight less than or equal to 1000 gm) who received a taurine-free total parenteral nutrition solution for 32 to 49 days (group P) and who subsequently were formula fed and (2) eight sick infants matched by gestational age and birth weight, who received formula or human milk from day 3 to 4 of life (group E). Ten healthy full-term infants ranging in age from 1 to 18 weeks and fed with formula provided normal values (group C). Significantly lower mean plasma taurine values (range 1.59 to 3.43 mumol/dl) were found between postnatal weeks 3 and 7 in group P compared with group E (range 5.54 to 6.97 mumol/dl) and with group C (5.6 +/- 0.34 mumol/dl). After initiation of feeding, plasma taurine concentrations in group P increased to normal. Markedly elevated values of mean fractional excretion of taurine, 38% to 56%, were found between weeks 3 and 5 in group P and E compared with group C (15.5 +/- 3.2%). In contrast, during the same period, low urinary taurine values (4.9% to 6.7%) were found in two larger, older infants receiving total parenteral nutrition whose plasma taurine values were in the normal range. After week 5, urinary taurine values were in the control range in all groups. We conclude that the absence of taurine in total parenteral nutrition solutions administered to very low birth weight infants and the limited ability of the immature kidney to adapt to low taurine intake by "up-regulation" of tubular taurine reabsorption may result in depleted taurine body pools during the first weeks of life. This inability to conserve taurine by the immature nephron could potentially have a deleterious effect on the developing brain and retina in these infants, and indicates a possible need for taurine supplementation.     

Pasteurization of mother's own milk reduces fat absorption and growth in preterm infants

AIM: A randomized study was conducted to evaluate whether pasteurized milk (Holder pasteurization 62.5 degrees C, 30 min) reduces fat absorption and growth in preterm infants. METHODS: Preterm infants (825-1325 g) born with gestational age < or =30 weeks were randomized into two groups, of which one started with pasteurized own mother's milk for 1 week and continued with raw milk the following week, and a second group was fed in reverse order. By using this design the infants served as their own controls. At the end of each week, a 72-h fat balance was performed and growth was monitored. RESULTS: We found, on an average, 17% higher fat absorption with raw as compared to pasteurized milk. Infants gained more weight and linear growth assessed as knee-heel length was also greater during the week they were fed raw milk as compared to the week they were fed pasteurized milk. CONCLUSION: Feeding preterm infants pasteurized as compared to raw own mother's milk reduced fat absorption. When the infants were fed raw milk, they gained more in knee-heel length compared to when they were fed pasteurized milk.     

Nitrogen and fat balances in very low birth weight infants fed human milk fortified with human milk or bovine milk protein

The study was designed to compare two different human milk fortifiers in a group of very low birth weight (VLBW) infants by analysing nitrogen and fat balances, serum concentrations of alpha-amino-nitrogen, urea, and prealbumin as well as growth rates when human milk enriched with one of the two studied fortifiers was fed to the infants. Fortifier A contained different bovine proteins, peptides and amino acids and had an amino acid composition comparable to that of the nutritional available proteins in human milk, with carbohydrates, and minerals. Fortifier B was composed of freeze-dried skimmed human milk and minerals to achieve a similar macronutrient composition in both fortifiers.Eleven infants were fed with human milk enriched with fortifier A and 13 with fortifier B. After a 10-day equilibration period, a 3-day metabolic balance was performed. On the 14th day of the study blood was obtained preprandially for serum analysis and growth rates were estimated. The nitrogen absorption rate (93.8% vs 93.5%) as well as the retention rate (80.8% vs 78.5%) were no different between the groups. The fat absorption rate (92.3% vs 91.5%) as well as the weight gain (32.1 vs 31.1 g/day) were similar and there were no differences in the serum parameters studied. The results indicate that feeding VLBW infants with human milk enriched with a well-balanced bovine fortifier fulfil their nutritional requirements as well as diets composed exclusively of human milk protein.     

Fecal cholesterol excretion in preterm infants fed breast milk or formula with different cholesterol contents

In 44 very low-birth-weight infants, fecal cholesterol excretion was measured and in 29 other infants serum total cholesterol concentrations in response to different cholesterol intakes were studied. The infants received fortified breast milk (mean cholesterol content 15.3mg/dl) or were fed either a standard preterm formula (cholesterol content 5.5mg/dl) or the same formula but with a modified lipid composition (long chain polyunsaturated fatty acid concentration closely related to breast milk fat) and 30 mg of cholesterol/dl. In the group fed the high cholesterol formula, fecal cholesterol excretion was significantly higher (35.5mmol/kg/day) than in the groups fed breast milk or the standard formula (20.1 and 18.2mmol/kg/day). Cholesterol balance in the group fed the high cholesterol formula (21.8mg/kg/day) was significantly higher than in the group fed breast milk (+8.6mg/kg/day). In the infants fed the low cholesterol formula the balance was negative (-7.7 mg/ kg/day). Serum concentrations of total cholesterol were similar in the groups fed breast milk or the high cholesterol formula (3.47 and 3.51 mmol/1), but significantly higher than in the group fed the low cholesterol formula (3.15 mmol/1). The data suggest that preterm infants are able to regulate a higher cholesterol intake than during breast feeding by increasing fecal cholesterol excretion as well as decreasing endogenous synthesis.     

Supplementation of pooled human milk with casein hydrolysate: energy and nitrogen balance and weight gain composition in very low birth weight infants

Growth and nitrogen and energy balances were studied with a combined technique of nutrient balance and indirect calorimetry measurement in two groups of eight very low birth weight infants fed pooled pasteurized human milk (HM) or cow's milk casein hydrolysate supplemented HM (HM-Pr). There was no difference in the amount of energy absorbed (91 +/- 17 kcal/kg/day with HM-Pr versus 95 +/- 8 with HM-P) or in the growth rate. The infants fed HM-Pr had a higher nitrogen intake (602 +/- 80 versus 395 +/- 64 mg/kg/day; p less than 0.001), urinary nitrogen excretion (160 +/- 64 versus 78 +/- 16 mg/kg/day; p less than 0.005) and nitrogen retention (326 +/- 32 versus 252 +/- 48 mg/kg/day; p less than 0.01). They also had increased plasma concentrations of essential amino acids, urea nitrogen, and total protein without metabolic imbalance. Energy expenditure was higher (58 versus 49 kcal/kg/day; p less than 0.005) and energy storage lower (33 versus 47 kcal/kg/day; p less than 0.05) with HM-Pr. In percent of weight gain, protein and fat accretion represented 12 and 14% in HM-Pr group versus 10 and 27% in HM group. Very low birth weight infants fed casein hydrolysate supplemented pooled HM achieved a growth rate and a weight gain composition similar to the fetus.