Longitudinal analysis of macronutrients and minerals in human milk produced by mothers of preterm infants

Is targeted fortification of human breast milk an optimal nutrition strategy for preterm infants? An interventional study

Background

Fortifying human milk contributes to the prevention of postnatal growth failure in preterm infants. Because of the natural variability of human milk, targeted fortification of human milk has been advocated. However, data regarding the efficacy and safety of prolonged targeted fortification are scarce. We aimed to assess the safety of targeted fortification of human milk in preterm infants compared with standard fortification, as well as the effects on infant growth.

Methods

We conducted an interventional study during hospital stay in healthy very low birth weight preterm infants who were exclusively fed human milk. Pools of human milk collected for 24 h were analysed using mid-infrared transmission spectroscopy. Targeted fortification of human milk was performed by adding macronutrients to native human milk to obtain optimal ratios of fat (4.4 g), carbohydrates (8.8 g), and protein (3 g) per 100 ml. The intervention period lasted 4–7 weeks. Weekly weight and daily growth rates were compared with those of a standardized fortification group of very low birth weight preterm infants who received standard fortified human milk (n = 10). The osmolality as well as the metabolic and gastrointestinal tolerance were monitored. Intergroup differences were evaluated using the Mann–Whitney U-test.

Results

A total of 10 preterm infants (birth weight 1223 ± 195 g; gestational age 29.1 ± 1.03 weeks) were enrolled and 118 samples of pooled milk were analysed. On average, 1.4 ± 0.1 g of protein, 2.3 ± 0.5 g of carbohydrate, and 0.3 ± 0.1 g of fat per 100 ml were added to the milk. Osmolality values after target fortification were within recommended limits (376 ± 66 mOsml/kg). Weekly weight gain (205.5 g; 95 % CI 177–233 vs 155 g; 95 % CI 132–178; p = 0.025) and daily growth rates (15.7 g/kg/day; 95 % CI 14.5–16.9 vs 12.3 g/kg/day; 95 % CI 10.7–13.9; p = 0.005) were higher in infants receiving target fortification than in infants receiving standardized fortification. The infants receiving targeted fortified milk consumed similar volumes as infants in the standardized fortification group (148 ± 4.5 vs 146 ± 4 ml/kg/day). No signs of either gastrointestinal or metabolic intolerance were observed.

Conclusions

Target fortification appears to promote growth in very low birth weight preterm infants without any detrimental effects.

Trial registration NCT02716337

Longitudinal evolution of true protein, amino acids and bioactive proteins in breast milk: a developmental perspective

The protein content of breast milk provides a foundation for estimating protein requirements of infants. Because it serves as a guideline for regulatory agencies issuing regulations for infant formula composition, it is critical that information on the protein content of breast milk is reliable. We have therefore carried out a meta-analysis of the protein and amino acid contents of breast milk and how they evolve during lactation. As several bioactive proteins are not completely digested in the infant and therefore represent "non-utilizable" protein, we evaluated the quantity, mechanism of action and digestive fate of several major breast milk proteins. A better knowledge of the development of the protein contents of breast milk and to what extent protein utilization changes with age of the infant will help improve understanding of protein needs in infancy. It is also essential when designing the composition of infant formulas, particularly when the formula uses a "staging" approach in which the composition of the formula is modified in stages to reflect changes in breast milk and changing requirements as the infant ages.

Simultaneous quantification of α-lactalbumin and β-casein in human milk using ultra-performance liquid chromatography with tandem mass spectrometry based on their signature peptides and winged isotope internal standards

In recent years, there is an increasing need to measure the concentration of individual proteins in human milk, instead of total human milk proteins. Due to lack of human milk protein standards, there are only few quantification methods established. The objective of the present work was to develop a simple and rapid quantification method for simultaneous determination of α-lactalbumin and β-casein in human milk using signature peptides according to a modified quantitative proteomics strategy. The internal standards containing the signature peptide sequences were synthesized with isotope-labeled amino acids. The purity of synthesized peptides as standards was determined by amino acid analysis method and area normalization method. The contents of α-lactalbumin and β-casein in human milk were measured according to the equimolar relationship between the two proteins and their corresponding signature peptides. The method validation results showed a satisfied linearity (R(2)>0.99) and recoveries (97.2-102.5% for α-lactalbumin and 99.5-100.3% for β-casein). The limit of quantification for α-lactalbumin and β-casein was 8.0mg/100g and 1.2mg/100g, respectively. CVs for α-lactalbumin and β-casein in human milk were 5.2% and 3.0%. The contents of α-lactalbumin and β-casein in 147 human milk samples were successfully determined by the established method and their contents were 205.5-578.2mg/100g and 116.4-467.4mg/100g at different lactation stages. The developed method allows simultaneously determination of α-lactalbumin and β-casein in human milk. The quantitative strategy based on signature peptide should be applicable to other endogenous proteins in breast milk and other body fluids.

One Extra Gram of Protein to Preterm Infants From Birth to 1800 g: A Single-Blinded Randomized Clinical Trial

OBJECTIVE

The aim of the study was to evaluate the effect on growth and neurodevelopment of increasing amino acid (AA) during parenteral nutrition and protein intake during enteral nutrition in extremely low birth-weight infants starting from birth to day of reaching 1800 g body weight.

METHODS

We randomized preterm infants with birth weight 500 to 1249 g either to a high AA/protein intake (HiP [high protein]: parenteral nutrition = 3.5 AA, enteral nutrition = 4.6 protein g · kg · day) or to a standard of care group (StP [standard protein]: parenteral nutrition = 2.5 AA, enteral nutrition = 3.6 protein g · kg · day). The primary outcome was weight gain from birth to 1800 g.

RESULTS

TWO:: hundred twenty-six patients were screened, 164 completed the study and were analyzed (82 StP and 82 HiP). Cumulative AA/protein intake from birth to 1800 g was 178 ± 42 versus 223 ± 45 g/kg in the StP versus HiP group respectively, P < 0.0001.Blood urea was higher in HiP than in StP group both during parenteral and enteral nutrition (P = 0.004).Weight gain from birth to 1800 g was 12.3 ± 1.6 in StP and 12.6 ± 1.7 g · kg · day in HiP group (P = 0.294). We found no difference in any growth parameters neither during hospital stay nor at 2 years corrected age. Bayley III score at 24 months corrected age was 93.8 ± 12.9 in StP group and 94.0 ± 13.9 in the HiP group, P = 0.92.

CONCLUSIONS

Increasing AA/protein intake both during parenteral and enteral nutrition does not improve growth and neurodevelopment of small preterm infants 500 to 1249 g birth weight.

The Effect of Gestational and Lactational Age on the Human Milk Metabolome

Human milk is the ideal nutrition source for healthy infants during the first six months of life and a detailed characterisation of the composition of milk from mothers that deliver prematurely (<37 weeks gestation), and of how human milk changes during lactation, would benefit our understanding of the nutritional requirements of premature infants. Individual milk samples from mothers delivering prematurely and at term were collected. The human milk metabolome, established by nuclear magnetic resonance (NMR) spectroscopy, was influenced by gestational and lactation age. Metabolite profiling identified that levels of valine, leucine, betaine, and creatinine were increased in colostrum from term mothers compared with mature milk, while those of glutamate, caprylate, and caprate were increased in mature term milk compared with colostrum. Levels of oligosaccharides, citrate, and creatinine were increased in pre-term colostrum, while those of caprylate, caprate, valine, leucine, glutamate, and pantothenate increased with time postpartum. There were differences between pre-term and full-term milk in the levels of carnitine, caprylate, caprate, pantothenate, urea, lactose, oligosaccharides, citrate, phosphocholine, choline, and formate. These findings suggest that the metabolome of pre-term milk changes within 5–7 weeks postpartum to resemble that of term milk, independent of time of gestation at pre-mature delivery.

α-Tocopherol in breast milk of women with preterm delivery after a single postpartum oral dose of vitamin E

We evaluated the effect of maternal vitamin E supplementation on the α-tocopherol concentrations of colostrum, transitional milk and mature milk of women who had given birth prematurely. This longitudinal randomised-controlled trial divided eighty-nine women into two groups: a control group and a supplemented group. Blood and breast milk were collected from all the participants after delivery. Next, each woman in the supplemented group received 400 IU of RRR-α-tocopheryl acetate. Further breast milk samples were collected 24 h after the first collection, as well as 7 and 30 d after delivery. α-Tocopherol concentrations were determined by HPLC. The baseline α-tocopherol concentrations in the maternal serum of the two groups were similar: 1159·8 (sd 292·4) μg/dl (27·0 (SD 6·8) μmol/l) for the control group and 1128·3 (sd 407·2) μg/dl (26·2 (SD 9·5) μmol/l) for the supplemented group. None of the women was vitamin E deficient. Breast milk α-tocopherol concentrations increased by 60 % 24 h after supplementation in the intervention group and did not increase at all in the control group. α-Tocopherol concentration of the transitional milk in the supplemented group was 35 % higher compared with the control group. α-Tocopherol concentrations of the mature milk in both groups were similar. Maternal supplementation with 400 IU of RRR-α-tocopherol increased the vitamin E concentrations of the colostrum and transitional milk, but not of the mature milk. This study presents relevant information for the design of strategies to prevent and combat vitamin E deficiency in the risk group of preterm infants.

Urine color as an indicator of urine concentration in pregnant and lactating women

Aim

Urine concentration measured via osmolality (U_OSM) and specific gravity (U_SG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine color (U_COL) may be a practical, surrogate marker for whole-body hydration status.

Purpose

To determine whether U_COL was a valid measure of urine concentration in PREG and LACT, and pair-matched non-pregnant, non-lactating control women (CON).

Methods

Eighteen PREG/LACT (age 31 ± 1 years, pre-pregnancy BMI 24.3 ± 5.9 kg m⁻²) and eighteen CON (age 29 ± 4 years, BMI 24.1 ± 3.7 kg m⁻²) collected 24-h and single-urine samples on specified daily voids at five time points (15 ± 2, 26 ± 1, and 37 ± 1 weeks gestation, 3 ± 1 and 9 ± 1 weeks postpartum during lactation; CON visits were separated by similar time intervals) for measurement of 24-h U_OSM, U_SG, and U_COL and single-sample U_OSM and U_COL.

Results

Twenty-four-hour U_COL was significantly correlated with 24-h U_OSM (r = 0.6085–0.8390, P < 0.0001) and 24-h U_SG (r = 0.6213–0.8985, P < 0.0001) in all groups. A 24-h U_COL ≥ 4 (AUC = 0.6848–0.9513, P < 0.05) and single-sample U_COL ≥ 4 (AUC = 0.9094–0.9216, P < 0.0001) indicated 24-h U_OSM ≥ 500 mOsm kg⁻¹ (representing inadequate fluid intake) in PREG, LACT, and CON.

Conclusions

Urine color was a valid marker of urine concentration in all groups. Thus, PREG, LACT, and CON can utilize U_COL to monitor their daily fluid balance. Women who present with a U_COL ≥ 4 likely have a U_OSM ≥ 500 mOsm kg⁻¹ and should increase fluid consumption to improve overall hydration status.

MicroRNAs in Breastmilk and the Lactating Breast: Potential Immunoprotectors and Developmental Regulators for the Infant and the Mother

Human milk (HM) is the optimal source of nutrition, protection and developmental programming for infants. It is species-specific and consists of various bioactive components, including microRNAs, small non-coding RNAs regulating gene expression at the post-transcriptional level. microRNAs are both intra- and extra-cellular and are present in body fluids of humans and animals. Of these body fluids, HM appears to be one of the richest sources of microRNA, which are highly conserved in its different fractions, with milk cells containing more microRNAs than milk lipids, followed by skim milk. Potential effects of exogenous food-derived microRNAs on gene expression have been demonstrated, together with the stability of milk-derived microRNAs in the gastrointestinal tract. Taken together, these strongly support the notion that milk microRNAs enter the systemic circulation of the HM fed infant and exert tissue-specific immunoprotective and developmental functions. This has initiated intensive research on the origin, fate and functional significance of milk microRNAs. Importantly, recent studies have provided evidence of endogenous synthesis of HM microRNA within the human lactating mammary epithelium. These findings will now form the basis for investigations of the role of microRNA in the epigenetic control of normal and aberrant mammary development, and particularly lactation performance.

Changes in preterm human milk composition with particular reference to introduction of mixed feeding

OBJECTIVE

To study the changes in composition of preterm milk till 6 months of age.

METHODS

Milk samples from 33, 19, 7 and 12 lactating mothers (delivered <34 weeks) were analyzed on days 7, 28, 90 and 180, respectively.

RESULTS

Triglyceride and sodium concentrations increased significantly with time and protein concentration decreased significantly over 180 days. Sodium (P=0.02) and triglyceride concentrations (P=0.06) were higher in milk samples of mothers who had introduced mixed feeding by 6 months post natal age (n=6) compared to exclusively breast-feeding mothers (n=6); but lactose and protein content was not significantly different.

CONCLUSIONS

Milk of preterm mothers has higher amount of triglycerides and sodium during introduction of mixed feeding.

MiRNA Analysis by Quantitative PCR in Preterm Human Breast Milk Reveals Daily Fluctuations of hsa-miR-16-5p

Background and Aims

Human breast milk is an extremely dynamic fluid containing many biologically-active components which change throughout the feeding period and throughout the day. We designed a miRNA assay on minimized amounts of raw milk obtained from mothers of preterm infants. We investigated changes in miRNA expression within month 2 of lactation and then over the course of 24 hours.

Materials and Methods

Analyses were performed on pooled breast milk, made by combining samples collected at different clock times from the same mother donor, along with time series collected over 24 hours from four unsynchronized mothers. Whole milk, lipids or skim milk fractions were processed and analyzed by qPCR. We measured hsa-miR-16-5p, hsa-miR-21-5p, hsa-miR-146-5p, and hsa-let-7a, d and g (all -5p). Stability of miRNA endogenous controls was evaluated using RefFinder, a web tool integrating geNorm, Normfinder, BestKeeper and the comparative ΔΔCt method.

Results

MiR-21 and miR-16 were stably expressed in whole milk collected within month 2 of lactation from four mothers. Analysis of lipids and skim milk revealed that miR-146b and let-7d were better references in both fractions. Time series (5H-23H) allowed the identification of a set of three endogenous reference genes (hsa-let-7d, hsa-let-7g and miR-146b) to normalize raw quantification cycle (Cq) data. We identified a daily oscillation of miR-16-5p.

Perspectives

Our assay allows exploring miRNA levels of breast milk from mother with preterm baby collected in time series over 48–72 hours.

Effects of different arachidonic acid supplementation on psychomotor development in very preterm infants; a randomized controlled trial

Background & aims

Nutritional supplementation with polyunsaturated fatty acids is important in preterm infants neurodevelopment, but it is not known if the omega-6/omega-3 ratio affects this process. This study was designed to determine the effects of a balanced contribution of arachidonic acid in very preterm newborns fed with formula milk.

Methods

This was a randomized trial, in which newborns <1500 g and/or <32 weeks gestational age were assigned to one of two groups, based on the milk formula they would receive during the first year of life. Initially, 60 newborns entered the study, but ultimately, group A was composed of 24 newborns, who were given formula milk with an ω-6/ω-3 ratio of 2/1, and Group B was composed of 21 newborns, given formula milk with an ω-6/ω-3 ratio of 1/1. The infants were followed up for two years: growth, visual-evoked potentials, brainstem auditory-evoked potentials, and plasma fatty acids were periodically measured, and psychomotor development was assessed using the Brunet Lézine scale at 24 months corrected age. A control group, for comparison of Brunet Lézine score, was made up of 25 newborns from the SEN1500 project, who were fed exclusively with breast milk.

Results

At 12 months, arachidonic acid values were significantly higher in group A than in group B (6.95 ± 1.55 % vs. 4.55 ± 0.78 %), as were polyunsaturated fatty acids (41.02 ± 2.09 % vs. 38.08 ± 2.32 %) achieved a higher average. Group A achieved a higher average Brunet Lézine score at 24 months than group B (99.9 ± 9 vs. 90.8 ± 11, p =0.028). The Brunet Lézine results from group A were compared with the control group results, with very similar scores registered between the two groups (99.9 ± 9 vs. 100.5 ± 7). There were no significant differences in growth or evoked potentials between the two formula groups.

Conclusions

Very preterm infants who received formula with an ω-6/ω-3 ratio of 2/1 had higher blood levels of essential fatty acids during the first year of life, and better psychomotor development, compared with very preterm newborns who consumed formula with an ω-6/ω-3 of 1/1. Therefore, formula milk with an arachidonic acid quantity double that of docosahexaenoic acid should be considered for feeding very preterm infants.

Trial registration

ClinicalTrials.gov Identifier NCT02503020.

Breast milk composition and infant nutrient intakes during the first 12 months of life

BACKGROUND/OBJECTIVES

The objective of this study was to quantify human milk supply and intake of breastfed infants up to age 12 months. In addition, human milk composition was quantified per energetic macronutrient and fatty-acid composition in a subsample of lactating mothers.

SUBJECTS/METHODS

One hundred and seventy-four Italian breastfed children were followed using test-weighing and 3-day food protocols from birth to age 12 months. From a subsample of 30 mothers breast milk samples were collected at child ages one (T1), two (T2), three (T3) and six (T6) months, and were analyzed for the amount of protein, digestible carbohydrates, total lipids and fatty-acid composition.

RESULTS

One hundred and forty-two (82%) filled in at least one 3-day food protocol within the first 12 months of life and complied with test-weighing of all milk feeds. The number of valid food protocols declined from 126 infants at 1 month to 77 at 12 months of age. Only galactose, non-protein nitrogen and protein decreased significantly from age 1 to age 6 months of lactation. Maternal body mass index and age affected fatty-acid levels in human milk. Median human milk intake decreased from 625 ml at T1, over 724 ml at T3 to 477 ml/day at T6. Average energy and %energy from protein intake per day increased from 419 kcal (s.d. 99) and 8.4% (1.0) at T1, respectively, to 860 kcal (145) and 16.1% (2.6) at T12.

CONCLUSIONS

These data provide a reference range of nutrient intakes in breastfed infants and may provide guidance for defining optimal nutrient intakes for infants that cannot be fully breastfed.

Gene expression in breastmilk cells is associated with maternal and infant characteristics

Breastmilk is a rich source of cells with a heterogeneous composition comprising early-stage stem cells, progenitors and more differentiated cells. The gene expression profiles of these cells and their associations with characteristics of the breastfeeding mother and infant are poorly understood. This study investigated factors associated with the cellular dynamics of breastmilk and explored variations amongst women. Genes representing different breastmilk cell populations including mammary epithelial and myoepithelial cells, progenitors, and multi-lineage stem cells showed great variation in expression. Stem cell markers ESRRB and CK5, myoepithelial marker CK14, and lactocyte marker α-lactalbumin were amongst the genes most highly expressed across all samples tested. Genes exerting similar functions, such as either stem cell regulation or milk production, were found to be closely associated. Infant gestational age at delivery and changes in maternal bra cup size between pre-pregnancy and postpartum lactation were associated with expression of genes controlling stemness as well as milk synthesis. Additional correlations were found between genes and dyad characteristics, which may explain abnormalities related to low breastmilk supply or preterm birth. Our findings highlight the heterogeneity of breastmilk cell content and its changes associated with characteristics of the breastfeeding dyad that may reflect changing infant needs.

Human Milk Analysis Using Mid-Infrared Spectroscopy

BACKGROUND

The composition of human milk is known to vary with length of gestation, stage of lactation, and other factors. Human milk contains all nutrients required for infant health but requires fortification to meet the needs of low-birth-weight infants. Without a known nutrient profile of the mother's milk or donor milk fed to a baby, the composition of the fortified product is only an estimate. Human milk analysis has the potential to improve the nutrition care of high-risk newborns by increasing the information about human milk composition. Equipment to analyze human milk is available, and the technology is rapidly evolving. This pilot study compares mid-infrared (MIR) spectroscopy to reference laboratory milk analysis.

METHODS

After obtaining informed consent, we collected human milk samples from mothers of infants weighing <2 kg at birth. Duplicate samples were analyzed for macronutrients by MIR and by reference laboratory analysis including Kjeldahl for protein, Mojonnier for fat, and high-pressure liquid chromatography for lactose. Intraclass correlation coefficients, Bland-Altman scatter plots, and paired t tests were used to compare the two methods.

RESULTS

No significant differences were detected between the macronutrient content of human milk obtained by MIR vs reference laboratory analysis.

CONCLUSIONS

MIR analysis appears to provide an accurate assessment of macronutrient content in expressed human milk from mothers of preterm infants. The small sample size of this study limits confidence in the results. Measurement of lactose is confounded by the presence of oligosaccharides. Human milk analysis is a potentially useful tool for establishing an individualized fortification plan.

Gastric Emptying and Curding of Pasteurized Donor Human Milk and Mother's Own Milk in Preterm Infants

We evaluated the effects of fortification and composition on gastric emptying and curding in un/fortified pairs of mother's own milk (MOM, n = 17) and pasteurized donor human milk (PDHM, n = 15) in preterm infants. Retained meal proportions (%) and curding were determined from sonography. Immediate and subsequent postprandial % were higher for PDHM (23%, P = 0.026; 15%, P = 0.006) and fortified meals (31.5%; 8.8%, both P < 0.001), whereas higher casein, whey, and lactose concentrations were associated with lower immediate postprandial % (all P < 0.006). Curding did not affect emptying. Influences of fortification, pasteurization, and differing breast milk compositions are small and unlikely implicated in preterm feeding intolerance.

A pilot study on the protein composition of induced nonpuerperal human milk

BACKGROUND

Our understanding of the components of human puerperal milk is extensive and increasing, yet the literature on nonpuerperal human milk has been limited to studies that measure the success of induced lactation.

OBJECTIVE

This study aimed to describe the composition of total protein and key bioactive proteins when lactation is induced in nonpuerperal women.

METHODS

Two women who induced lactation in the absence of pregnancy provided weekly milk samples over a 2-month period for analysis of total protein, secretory immunoglobulin A (sIgA), lysozyme, and lactoferrin. Composition was compared to the mature milk of 3 puerperal control subjects who were 11 months postpartum.

RESULTS

Median total protein for subject A was 2.30 g/dL (interquartile range [IQR] = 0.46) and showed a significant downward trend over time (P < .0001), whereas the median total protein for subject B was 2.21 g/dL (IQR = 0.18) and showed a nonsignificant decline (P = .232). Total protein in both nonpuerperal subjects was elevated compared to control subjects. Secretory IgA activity declined for both nonpuerperal subjects over time, whereas lysozyme concentrations increased over time. Both sIgA and lysozyme approached the levels seen in the puerperal controls. Lactoferrin levels remained stable for both nonpuerperal subjects and were elevated compared to puerperal milk samples.

CONCLUSION

This pilot study suggests that nonpuerperal milk has similar or higher levels of total protein, sIgA, lactoferrin, and lysozyme compared to puerperal, mature milk at 11 months postpartum, which warrants more attention as adoptive mothers increasingly choose to induce lactation.

Linking fat intake, the intestinal microbiome, and necrotizing enterocolitis in premature infants

Components of diet, including the total amounts and specific types of fat, affect the composition of the intestinal microbiome in both animal models and cohort studies of humans. Amounts of total fat and specific fatty acids (FA) are some of the most variable nutritional components of breast milk. Evaluations of the microbiome in premature infants have shown decreased diversity of species and increased proportions of potentially pathogenic bacteria. Microbial patterns in premature infants may be affected by nutritional fat intake, altering risk of diseases such as necrotizing enterocolitis. Dietary FA may also impact disease susceptibility through molecular mechanisms. Specifically, intestinal Toll-like receptor 4 expression is altered by manipulation of FA in murine models. Abnormal increased expression of Toll-like receptor 4, the receptor for lipopolysaccharide, has been implicated in necrotizing enterocolitis. This report will review the role of dietary fat in the composition of the intestinal microbiome, the extreme variability of FA intake in premature infants, and associations of both dysbiosis and FA intake with the development of necrotizing enterocolitis.

Maternal fucosyltransferase 2 status affects the gut bifidobacterial communities of breastfed infants

BACKGROUND

Individuals with inactive alleles of the fucosyltransferase 2 gene (FUT2; termed the 'secretor' gene) are common in many populations. Some members of the genus Bifidobacterium, common infant gut commensals, are known to consume 2'-fucosylated glycans found in the breast milk of secretor mothers. We investigated the effects of maternal secretor status on the developing infant microbiota with a special emphasis on bifidobacterial species abundance.

RESULTS

On average, bifidobacteria were established earlier and more often in infants fed by secretor mothers than in infants fed by non-secretor mothers. In secretor-fed infants, the relative abundance of the Bifidobacterium longum group was most strongly correlated with high percentages of the order Bifidobacteriales. Conversely, in non-secretor-fed infants, Bifidobacterium breve was positively correlated with Bifidobacteriales, while the B. longum group was negatively correlated. A higher percentage of bifidobacteria isolated from secretor-fed infants consumed 2'-fucosyllactose. Infant feces with high levels of bifidobacteria had lower milk oligosaccharide levels in the feces and higher amounts of lactate. Furthermore, feces containing different bifidobacterial species possessed differing amounts of oligosaccharides, suggesting differential consumption in situ.

CONCLUSIONS

Infants fed by non-secretor mothers are delayed in the establishment of a bifidobacteria-laden microbiota. This delay may be due to difficulties in the infant acquiring a species of bifidobacteria able to consume the specific milk oligosaccharides delivered by the mother. This work provides mechanistic insight into how milk glycans enrich specific beneficial bacterial populations in infants and reveals clues for enhancing enrichment of bifidobacterial populations in at risk populations - such as premature infants.

Changes in preterm breast milk nutrient content in the first month

BACKGROUND

The primary aim of the study was to investigate the changes in composition of breast milk from mothers with preterm infants (gestation age < 35 weeks) during the first 4-6 weeks of lactation.

METHODS

Breast milk from 17 mothers who had delivered preterm infants was collected longitudinally for 4-6 weeks. Breast milk from 15 mothers of full-term infants was also collected at the 1(st) week and 4(th) week. Fat, protein, lactose, energy, minerals (calcium and phosphate), and immune components [secretory immunoglobulin A (IgA), leptin, lysozyme, and lactoferrin] content were measured weekly in each participant. A mid-infrared human milk analyzer was used to measure the protein, fat, and lactose contents. Calcium and phosphate components were checked via spectrophotometry. The concentrations of major immune components (secretory IgA, lactoferrin, lysozyme, and leptin) were quantified using enzyme-linked immunosorbent assay kits.

RESULTS

Eighty samples from 17 preterm mothers were collected. The mean gestational age was 29.88 ± 2.39 weeks. There were significant changes in nutrient components during these periods, with increases in lactose (p < 0.001), lipid (p = 0.001), calorie (p = 0.012), and phosphate (p = 0.022) concentration and decreases in protein (p < 0.001) and secretory IgA (p < 0.001) concentration. There were no differences in calcium (p = 0.919), lactoferrin (p = 0.841), leptin (p = 0.092), and lysozyme (p = 0.561) levels. Furthermore, there were no significant differences in most components of breast milk between full-term and preterm mothers.

CONCLUSION

The longitudinal study revealed significant changes in macronutrient contents and secretory IgA concentration in preterm milk over the 4-6 week period, which is compatible with the results of previous studies. The quantification of phosphate in preterm breast milk was lower than the normal range, suggesting that close monitoring of body bone mass may be indicated. More studies are warranted to evaluate the clinical significance of alterations of major milk components during the postnatal stage.

Temporal trends in the inflammatory cytokine profile of human breastmilk

A longer lifetime duration of breastfeeding may decrease the risk of breast cancer by reducing breast inflammation and mitigating inflammatory cytokine expression during postlactational involution. However, little is known about how the inflammatory cytokine profile in human breastmilk changes over time. To study temporal trends in breastmilk cytokine expression, we measured 80 human cytokines in the whey fraction of breastmilk samples from 15 mothers at 1, 4, 8, and 12 weeks postpartum. We used mixed models to identify temporal changes in cytokine expression and investigated parity status (multiparous vs. primiparous) as a potential confounder. Nine cytokines (monocyte chemoattractant protein-1, epithelial-derived neutrophil-activating protein-78, hepatocyte growth factor, insulin-like growth factor-binding protein-1, interleukin-16, interleukin-8, macrophage colony-stimulating factor, osteoprotegerin, and tissue inhibitor of metallopeptidase-2) had significantly decreased expression with increasing breastfeeding duration; all nine have known roles in breast involution, inflammation, and cancer and may serve as biomarkers of changing breast microenvironment. No cytokine significantly increased in level over the study period. Total protein concentration significantly decreased over time (p<0.0001), which may mediate the association between length of breastfeeding and inflammatory cytokine expression. Parity status did not confound temporal trends, but levels of several cytokines were significantly higher among multiparous versus primiparous women. Our results suggest that inflammatory cytokine expression during lactation is dynamic, and expressed milk may provide a noninvasive window into the extensive biological changes that occur in the postpartum breast.

Intake and macronutrient content of human milk given to extremely preterm infants

BACKGROUND

Human milk (HM) is the preferred basis of nutrition for infants, including those born prematurely. Information on HM macronutrient content is necessary to optimize nutritional support of preterm infants.

OBJECTIVES

This study aimed to describe the types and amounts of enteral feeds given to Swedish extremely preterm infants during hospitalization and to investigate the energy and macronutrient contents in HM given to these infants.

METHODS

A population-based study of Swedish extremely preterm infants (n = 586) born before 27 gestational weeks was conducted. Data on ingested volumes of different milk during hospitalization and analyses of macronutrient content in HM samples were obtained from hospital records. Nutritional content of HM was determined by mid-infrared spectrophotometry analysis.

RESULTS

During the first 4 weeks of life, 99% of the infants were exclusively fed HM, and at 4 weeks of life, 70% of the infants received only mother's own milk (MOM). Nutritional content in 821 MOM samples was analyzed. Protein content in MOM decreased significantly from 2.2 to 1.2 g/100 mL during the first 112 postpartum days, whereas fat and energy content were highly variable within and between MOM samples. In addition, 354 samples of donor milk were analyzed. Content of protein, fat, and energy in pooled donor milk (n = 129) was lower compared to single donor milk.

CONCLUSION

Swedish extremely preterm infants receive MOM to a large extent during hospitalization. Protein, carbohydrates, and energy in MOM changed significantly with time. Weekly analyses of MOM during the first month of lactation would allow more individualized nutritional support for these vulnerable infants.

A systematic review and meta-analysis of the nutrient content of preterm and term breast milk

Background

Breast milk nutrient content varies with prematurity and postnatal age. Our aims were to conduct a meta-analysis of preterm and term breast milk nutrient content (energy, protein, lactose, oligosaccharides, fat, calcium, and phosphorus); and to assess the influence of gestational and postnatal age. Additionally we assessed for differences by laboratory methods for: energy (measured vs. calculated estimates) and protein (true protein measurement vs. the total nitrogen estimates).

Methods

Systematic review results were summarized graphically to illustrate the changes in composition over time for term and preterm milk. Since breast milk fat content varies within feeds and diurnally, to obtain accurate estimates we limited the meta-analyses for fat and energy to 24-hour breast milk collections.

Results

Forty-one studies met the inclusion criteria: 26 (843 mothers) preterm studies and 30 (2299 mothers) term studies of breast milk composition. Preterm milk was higher in true protein than term milk, with differences up to 35% (0.7 g/dL) in colostrum, however, after postnatal day 3, most of the differences in true protein between preterm and term milk were within 0.2 g/dL, and the week 10–12 estimates suggested that term milk may be the same as preterm milk by that age. Colostrum was higher than mature milk for protein, and lower than mature milk for energy, fat and lactose for both preterm and term milk. Breast milk composition was relatively stable between 2 and 12 weeks. With milk maturation, there was a narrowing of the protein variance. Energy estimates differed whether measured or calculated, from −9 to 13%; true protein measurement vs. the total nitrogen estimates differed by 1 to 37%.

Conclusions

Although breast milk is highly variable between individuals, postnatal age and gestational stage (preterm versus term) were found to be important predictors of breast milk content. Energy content of breast milk calculated from the macronutrients provides poor estimates of measured energy, and protein estimated from the nitrogen over-estimates the protein milk content. When breast milk energy, macronutrient and mineral content cannot be directly measured the average values from these meta-analyses may provide useful estimates of mother’s milk energy and nutrient content.

Cytokines, Chemokines, and Growth Factors in Banked Human Donor Milk for Preterm Infants

BACKGROUND

There has been a recent increase in availability of banked donor milk for feeding of preterm infants. This milk is pooled from donations to milk banks from carefully screened lactating women. The milk is then pasteurized by the Holder method to remove all microbes. The processed milk is frozen, banked, and sold to neonatal intensive care units (NICUs). The nutrient bioavailability of banked donor milk has been described, but little is known about preservation of immune components such as cytokines, chemokines, and growth factors (CCGF).

OBJECTIVE

The objective was to compare CCGF in banked donor milk with mother's own milk (MOM).

METHODS

Aliquots (0.5 mL) were collected daily from MOM pumped by 45 mothers of NICU-admitted infants weighing < 1500 grams at birth. All daily aliquots of each mother's milk were pooled each week during 6 weeks of an infant's NICU stay or for as long as the mother provided MOM. The weekly pooled milk was measured for a panel of CCGF through multiplexing using magnetic beads and a MAGPIX instrument. Banked donor milk samples (n = 25) were handled and measured in the same way as MOM.

RESULTS

Multiplex analysis revealed that there were levels of CCGF in banked donor milk samples comparable to values obtained from MOM after 6 weeks of lactation.

CONCLUSION

These data suggest that many important CCGF are not destroyed by Holder pasteurization.

Implementation of a human milk management center

Current hospital practices surrounding the use of human milk and fortification are suboptimal. Safety of milk preparation should be a priority, as should optimization of the milk to meet the nutritional needs of hospitalized infants. This article describes the implementation of a human milk management center (HMMC) at a children's hospital. This centralized center allows for milk to be safely prepared under aseptic technique. In addition, the HMMC staff can analyze milk composition. The widely variable nutrient composition of human milk has been well established and, therefore, should be considered when fortifying human milk. The HMMC staff have the ability to perform creamatocrits on milk, conduct human milk nutrient analysis, and make skim milk for infants. The processes for developing an HMMC are also detailed in this article.

Freezing and thawing effects on fat, protein, and lactose levels of human natural milk administered by gavage and continuous infusion

OBJECTIVES

to analyze the changes in human milk macronutrients: fat, protein, and lactose in natural human milk (raw), frozen and thawed, after administration simulation by gavage and continuous infusion.

METHOD

an experimental study was performed with 34 human milk samples. The infrared spectrophotometry using the infrared analysis equipment MilkoScan Minor® (Foss, Denmark) equipment was used to analyze the macronutrients in human milk during the study phases. The analyses were performed in natural (raw) samples and after freezing and fast thawing following two steps: gavage and continuous infusion. The non-parametric Wilcoxon test for paired samples was used for the statistical analysis.

RESULTS

the fat content was significantly reduced after administration by continuous infusion (p<0.001) during administration of both raw and thawed samples. No changes in protein and lactose content were observed between the two forms of infusion. However, the thawing process significantly increased the levels of lactose and milk protein.

CONCLUSION

the route of administration by continuous infusion showed the greatest influence on fat loss among all the processes required for human milk administration.

Protein intake and neurodevelopmental outcomes

There is a compelling body of literature that suggests that the provision of an inadequate amount of protein to preterm infants in the neonatal period has detrimental effects on the developing brain with the potential to result in long-term, neurodevelopmental sequelae. Although a great deal of indirect evidence implies that the provision of adequate amounts of protein may be associated with better neurodevelopmental outcomes, there remains a paucity of direct evidence that would allow us to draw any final conclusions.

Rapid measurement of human milk macronutrients in the neonatal intensive care unit: accuracy and precision of fourier transform mid-infrared spectroscopy

BACKGROUND

Although it is well established that human milk varies widely in macronutrient content, it remains common for human milk fortification for premature infants to be based on historic mean values. As a result, those caring for premature infants often underestimate protein intake. Rapid precise measurement of human milk protein, fat, and lactose to allow individualized fortification has been proposed for decades but remains elusive due to technical challenges.

OBJECTIVE

This study aimed to evaluate the accuracy and precision of a Fourier transform (FT) mid-infrared (IR) spectroscope in the neonatal intensive care unit to measure human milk fat, total protein, lactose, and calculated energy compared with standard chemical analyses.

METHODS

One hundred sixteen breast milk samples across lactation stages from women who delivered at term (n = 69) and preterm (n = 5) were analyzed with the FT mid-IR spectroscope and with standard chemical methods. Ten of the samples were tested in replicate using the FT mid-IR spectroscope to determine repeatability.

RESULTS

The agreement between the FT mid-IR spectroscope analysis and reference methods was high for protein and fat and moderate for lactose and energy. The intra-assay coefficients of variation for all outcomes were less than 3%.

CONCLUSION

The FT mid-IR spectroscope demonstrated high accuracy in measurement of total protein and fat of preterm and term milk with high precision.

Donor human milk bank data collection in north america: an assessment of current status and future needs

BACKGROUND

The Human Milk Banking Association of North America (HMBANA) is a nonprofit association that standardizes and facilitates the establishment and operation of donor human milk (DHM) banks in North America. Each HMBANA milk bank in the network collects data on the DHM it receives and distributes, but a centralized data repository does not yet exist. In 2010, the Food and Drug Administration recognized the need to collect and disseminate systematic, standardized DHM bank data and suggested that HMBANA develop a DHM data repository.

OBJECTIVES

This study aimed to describe data currently collected by HMBANA DHM banks and evaluate feasibility and interest in participating in a centralized data repository.

METHODS

We conducted phone interviews with individuals in different HMBANA milk banks and summarized descriptive statistics.

RESULTS

Eight of 13 (61.5%) sites consented to participate. All respondents collected donor demographics, and half (50%; n = 4) rescreened donors after 6 months of continued donation. The definition of preterm milk varied between DHM banks (≤ 32 to ≤ 40 weeks). The specific computer program used to house the data also differed. Half (50%; n = 4) indicated that they would consider participation in a centralized repository.

CONCLUSIONS

Without standardized data across all HMBANA sites, the creation of a centralized data repository is not yet feasible. Lack of standardization and transparency may deter implementation of donor milk programs in the neonatal intensive care unit setting and hinder benchmarking, research, and quality improvement initiatives.

Amino acid profiles in term and preterm human milk through lactation: a systematic review

Amino acid profile is a key aspect of human milk (HM) protein quality. We report a systematic review of total amino acid (TAA) and free amino acid (FAA) profiles, in term and preterm HM derived from 13 and 19 countries, respectively. Of the 83 studies that were critically reviewed, 26 studies with 3774 subjects were summarized for TAA profiles, while 22 studies with 4747 subjects were reviewed for FAA. Effects of gestational age, lactation stage, and geographical region were analyzed by Analysis of Variance. Data on total nitrogen (TN) and TAA composition revealed general inter-study consistency, whereas FAA concentrations varied among studies. TN and all TAA declined in the first two months of lactation and then remained relatively unchanged. In contrast, the FAA glutamic acid and glutamine increased, peaked around three to six months, and then declined. Some significant differences were observed for TAA and FAA, based on gestational age and region. Most regional TAA and FAA data were derived from Asia and Europe, while information from Africa was scant. This systematic review represents a useful evaluation of the amino acid composition of human milk, which is valuable for the assessment of protein quality of breast milk substitutes.

2'-fucosyllactose: an abundant, genetically determined soluble glycan present in human milk

Lactose is the preeminent soluble glycan in milk and a significant source of energy for most newborn mammals. Elongation of lactose with additional monosaccharides gives rise to a varied repertoire of free soluble glycans such as 2'-fucosyllactose (2'-FL), which is the most abundant oligosaccharide in human milk. In infants, 2'-FL is resistant to digestion and reaches the colon where it is partially fermented, behaving as soluble prebiotic fiber. Evidence also suggests that portions of small soluble milk glycans, including 2'-FL, are absorbed, thus raising the possibility of systemic biological effects. 2'-FL bears an epitope of the Secretor histo-blood group system; approximately 70-80% of all milk samples contain 2'-FL, since its synthesis depends on a fucosyltransferase that is not uniformly expressed. The fact that some infants are not exposed to 2'-FL has helped researchers to retrospectively probe for biological activities of this glycan. This review summarizes the attributes of 2'-FL in terms of its occurrence in mammalian phylogeny, its postulated biological activities, and its variability in human milk.

The human milk metabolome reveals diverse oligosaccharide profiles

Breast milk delivers nutrition and protection to the developing infant. There has been considerable research on the high-molecular-weight milk components; however, low-molecular-weight metabolites have received less attention. To determine the effect of maternal phenotype and diet on the human milk metabolome, milk collected at day 90 postpartum from 52 healthy women was analyzed by using proton nuclear magnetic resonance spectroscopy. Sixty-five milk metabolites were quantified (mono-, di-, and oligosaccharides; amino acids and derivatives; energy metabolites; fatty acids and associated metabolites; vitamins, nucleotides, and derivatives; and others). The biological variation, represented as the percentage CV of each metabolite, varied widely (4-120%), with several metabolites having low variation (<20%), including lactose, urea, glutamate, myo-inositol, and creatinine. Principal components analysis identified 2 clear groups of participants who were differentiable on the basis of milk oligosaccharide concentration and who were classified as secretors or nonsecretors of fucosyltransferase 2 (FUT2) gene products according to the concentration of 2'-fucosyllactose, lactodifucotetraose, and lacto-N-fucopentaose I. Exploration of the interrelations between the milk sugars by using Spearman rank correlations revealed significant positive and negative associations, including positive correlations between fucose and products of the FUT2 gene and negative correlations between fucose and products of the fucosyltransferase 3 (FUT3) gene. The total concentration of milk oligosaccharides was conserved among participants (%CV = 18%), suggesting tight regulation of total oligosaccharide production; however, concentrations of specific oligosaccharides varied widely between participants (%CV = 30.4-84.3%). The variability in certain milk metabolites suggests possible roles in infant or infant gut microbial development. This trial was registered at clinicaltrials.gov as NCT01817127.

Nutritional content of infant commercial weaning foods in the UK

BACKGROUND AND AIMS

Health professionals are frequently asked to advise on aspects of complementary feeding. This study aimed to describe the types of commercial infant foods available in the UK and provide an overview of their taste, texture and nutritional content in terms of energy, protein, carbohydrates, fat, sugar, iron, sodium and calcium.

METHOD

All infant foods produced by four main UK manufacturers and two more specialist suppliers were identified during October 2010-February 2011. Nutritional information for each product was collected from manufacturers' websites, products in store and via direct email enquiry.

RESULTS

Of the 479 products identified in this study 364 (79%) were ready-made spoonable foods; 44% (201) were aimed at infants from 4 months, and 65% of these were sweet foods. The mean (SD) energy content of ready-made spoonable foods was 282 (59) kJ per 100 g, almost identical to breast milk (283(16) kJ per 100 g). Similar spoonable family foods were more nutrient dense than commercial foods. Commercial finger foods were more energy dense, but had very high sugar content.

CONCLUSIONS

The UK infant food market mainly supplies sweet, soft, spoonable foods targeted from age 4 months. The majority of products had energy content similar to breast milk and would not serve the intended purpose of enhancing the nutrient density and diversity of taste and texture in infants' diets.

Human milk fortification with differing amounts of fortifier and its association with growth and metabolic responses in preterm infants

BACKGROUND

Fortification of human milk (HM) is a common clinical practice to adapt breast milk to the nutritional needs of very low birth weight (VLBW) infants. The optimal method for HM fortification remains to be determined, and a variety of protocols are currently used in neonatal intensive care units.

OBJECTIVE

It is believed that standard fortification is insufficient to meet the needs of VLBW infants. Therefore, we designed a randomized prospective study that investigated the effects of varying levels of blind fortification on short-term growth and metabolic responses of preterm infants.

METHODS

Eligible infants were randomized into 3 groups: standard fortification (SF), moderate fortification (MF), and aggressive fortification (AF). Short-term growth, feeding intolerance, and urea, calcium, phosphorus, and alkaline phosphatase levels were assessed.

RESULTS

There were 26, 29, and 29 infants in the SF, MF, and AF groups, respectively. The baseline characteristics of the groups were similar. Daily weight gain and length at discharge did not differ among the groups; however, head circumference was significantly higher in the MF and AF groups compared with the SF group. Urea, calcium, phosphorus, and alkaline phosphatase levels were similar between the groups.

CONCLUSION

We demonstrated that blind fortification of HM, even with higher amounts than recommended by manufacturers, did not cause any measured adverse effects on the metabolic response of preterm infants. Anthropometric measurements (except head circumference) were not different between the different dosages of fortification.

Variability in human milk composition: benefit of individualized fortification in very-low-birth-weight infants

BACKGROUND

Preterm infants fed fortified human milk (HM) grow more slowly than those fed preterm formulas. These differences could be related to the variability in the macronutrient composition of expressed HM, resulting in inadequate nutrient intake in relation to the estimated needs of the preterm infants.

OBJECTIVES

The aim of this article was to show the variability in HM composition from an infant's own mother's milk (OMM) or pooled HM from the milk bank. The second objective was to evaluate the advantages of individual fortification on nutritional intakes over standard fortification.

DESIGN

The macronutrient composition of 428 OMM, 138 HM pools from single donors, 224 pools from multiple donors, and 14 pools from colostral milk was determined by using a mid-infrared analyzer. Individualized fortification was performed after analysis of the milk samples in 2 steps: adjustment of fat content up to 4 g/dL, followed by the addition of an HM fortifier to provide 4.3 g · kg(-1) · d(-1) according to the daily prescribed volume of feeding. Nutritional intakes resulting from the individualized fortification were compared with calculated intakes resulting from standard fortification (HM fortifier: 4 packets/dL).

RESULTS

The variability in contents of fat, protein, and energy was high for all types of HM samples. Compared with standard fortification, individual fortification significantly reduced the variability in nutritional intakes, allowing the maintenance of protein intake and the protein:energy ratio in the range of the nutritional recommendations.

CONCLUSIONS

The variability in expressed HM with respect to its protein and energy content is high. This variability persists after standard fortification, possibly resulting in under- or overnutrition. Because both over- and undernutrition confer risks in later development, individualized fortification optimizes protein and energy intake.

The enigma to achieve normal postnatal growth in preterm infants--using parenteral or enteral nutrition?

AIM

To evaluate whether increasing the amount of amino acids and energy in parenteral nutrition combined with rapid increment of enteral feeding improves postnatal growth in preterm infants.

METHODS

Observational study; two consecutive year-cohorts of preterm infants; Cohort 2 received higher supplementation of parenteral amino acids and energy with more rapid enhancement of enteral feeding than Cohort 1. Nutritional intake, weight and head circumference (HC) were compared.

RESULTS

Cohort 2 [N: 79, gestational age (GA): 29.8 ± 2.2 weeks, birth weight (BW): 1248 ± 371 g] achieved full enteral feeds earlier (p < 0.001) and had a higher protein/energy intake during the first week (p < 0.001) than Cohort 1 (N: 68, GA: 29.5 ± 2.3 weeks, BW: 1261 ± 339 g). Both cohorts developed cumulative protein/energy deficits, but less in Cohort 2 (p < 0.01). Appropriate for gestational age infants (AGA) of Cohort 2 improved weight gain until week 5 (p < 0.01) compared to AGA of Cohort 1, nevertheless all infants demonstrated a decline in mean standard deviation score (>1) for weight at term. Small for GA infants failed to improve HC.

CONCLUSION

Improved parenteral intake may lead to improved short-term postnatal weight gain. Faster increase of enteral nutrition was well tolerated but failed to prevent nutritional deficits. Practising early enteral feeding with higher supplementation of nutrients may be needed and requires further study.

Investigation of short-term variations in term breast milk composition during repeated breast expression sessions

BACKGROUND

Breast milk composition can be affected by several factors, and it can exhibit short-term (weekly) variations. Investigating variations in breast milk composition is important to accurately estimate nutrient requirements of the infant.

OBJECTIVE

To investigate short-term changes in breast milk composition between left and right breasts, over a 3-week period within the first 6 months of lactation.

METHODS

The left and right breasts of the mothers of healthy, term infants (n = 23) were simultaneously expressed with an electric breast pump for 15 minutes, on 3 occasions within 3 weeks. Milk samples (5 mL) were collected from the total expression volume of each breast at each session. The macronutrient contents, total solids, and energy content were determined using a mid-infrared human milk analyzer. Mothers (n = 17) measured their 24-hour milk production, and the average 24-hour fat contents were also determined.

RESULTS

Over the 3 weekly sessions, no significant changes were found in macronutrient contents. On average, total solids (P = .04) and energy (P = .04) decreased by week 3 of follow-up sessions from 14 to 13 g/100 mL and from 82 to 76 Kcal/100 mL, respectively; however, these changes became insignificant when expression volume was taken into account. The macronutrient concentration was similar for the left and right breasts; however, milk composition varied markedly between mothers. Furthermore, average 24-hour fat content was significantly lower than the mean fat content from a single expression session (P < .01).

CONCLUSION

Our findings highlight that when determining the nutritional adequacy of a mother's milk, assuming an average concentration requires caution. The study findings illustrate the importance of using average 24-hour fat content of milk to obtain representative measures of infant energy intake.

White matter injury in preterm infants: could human milk play a role in its prevention?

Human milk has been found to be beneficial for the development of all newborns. It is protective during the development of the gastrointestinal tract, important in neurologic development, immune system function, and nourishment. Human milk has a number of components that aid in the anti-inflammatory process and free radical reduction and is a building block for neurologic development. Cerebral white matter injury is a common occurrence in preterm infants. Results of this injury can be seen into early childhood and throughout the life of the individual. White matter injury most frequently occurs because of hypoxia and the inflammatory process, which often results in the injury of myelinating oligodendrites. This article proposes the potential importance of human milk in slowing and preventing cerebral white matter injury because of the components in human milk that affect the inflammatory and free radical reduction processes. It also proposes its ability to provide nutrients essential to myelin development.

Human milk composition: nutrients and bioactive factors

This article provides an overview of the composition of human milk, its variation, and its clinical relevance. The composition of human milk is the biological norm for infant nutrition. Human milk also contains many hundreds to thousands of distinct bioactive molecules that protect against infection and inflammation and contribute to immune maturation, organ development, and healthy microbial colonization. Some of these molecules (eg, lactoferrin) are being investigated as novel therapeutic agents. Human milk changes in composition from colostrum to late lactation, within feeds, by gestational age, diurnally, and between mothers. Feeding infants with expressed human milk is increasing.

Human milk for the premature infant

Premature infants are at risk for growth failure, developmental delays, necrotizing enterocolitis, and late-onset sepsis. Human milk from women delivering prematurely has more protein and higher levels of bioactive molecules. Human milk must be fortified for premature infants to achieve adequate growth. Mother's own milk improves growth and neurodevelopment, decreases the risk of necrotizing enterocolitis and late-onset sepsis, and should be the primary enteral diet for premature infants. Donor milk is a resource for premature infants whose mothers are unable to provide an adequate supply of milk. Challenges include the need for pasteurization, nutritional and biochemical deficiencies, and limited supply.

Longitudinal analysis of protein glycosylation and β-casein phosphorylation in term and preterm human milk during the first 2 months of lactation

Human milk proteins provide term and preterm infants with both nutrition and protection. The objective of the present study was to examine longitudinal changes in the protein composition of term and preterm milk during the first 2 months of lactation, focusing on protein phosphorylation and glycosylation. Using gel electrophoresis, the relative concentration and glycosylation status of lactoferrin, secretory Ig A, β-casein, α-lactalbumin, serum albumin, bile salt-stimulated lipase, xanthine oxidoreductase, tenascin and macrophage mannose receptor 1 were measured in milk collected on days 7, 10, 14, 18, 21, 28 and 60 postpartum from preterm mothers (28-32 weeks gestation, n 17). The phosphorylation status of β-casein was also investigated. To determine if these variables differ in term and preterm milk, samples from term mothers (38-41 weeks gestation, n 8) collected on days 7, 14 and 30 of lactation were also analysed. The concentration of the abundant milk proteins decreased during lactation in term and preterm milk (P <0·05). No difference in protein glycosylation was observed, except for the glycoproteins serum albumin and tenascin. The phosphorylation of β-casein varied significantly between term and preterm milk. Further investigation is required to determine whether these modifications affect protein function and are clinically important to preterm infants.

Making the case for using donor human milk in vulnerable infants

Vulnerable infants are at an increased risk for feeding intolerance due to immaturity or dysfunction (ie, congenital anomaly or obstruction) of the gastrointestinal system and/or hemodynamic instability. Symptoms of feeding intolerance include vomiting, water-loss stools, increased abdominal girth, and increased gastric residuals. It has been well documented that human milk provides optimal nutrition for infants and decreases the incidence of feeding intolerance. Donor human milk can be used for these at-risk infants to supplement the mother's own milk supply if insufficient or if the mother has decided not to or is unable to provide human milk for her infant. Establishing a donor human milk program within your institution will allow an opportunity for all vulnerable infants to receive an exclusive human milk diet.