Changes in preterm breast milk nutrient content in the first month

Breast-feeding as protective factor against bronchopulmonary dysplasia in preterm infants

Breast-feeding is associated with fewer comorbidities in very-low-birth-weight (VLBW) preterm infants. Bronchopulmonary dysplasia (BPD) of VLBW infants is a multifactorial pathology in which nutritional aspects may be of special importance. The aim of this study is to determine, in a cohort of VLBW infants, whether breast milk nutrition is associated with a reduced prevalence and severity of BPD. A retrospective study was conducted to record the intake of mother's own milk (MOM), pasteurised donor human milk or preterm formula milk in the first 2 weeks of postnatal life of 566 VLBW newborns at our hospital during the period January 2008-December 2021. After applying the relevant exclusion criteria, data for 489 VLBW infants were analysed; 195 developed some degree of BPD. Moderate or severe BPD is associated with less weight gain. Moreover, the preferential ingestion of breast milk in the first and second postnatal weeks had effects associated with lower OR for BPD, which were statistically demonstrable for mild (OR 0·16; 95 % CI 0·03, 0·71) and severe (OR 0·08; 95 % CI 0·009, 0·91) BPD. Breast-feeding during the first weeks of postnatal life is associated with a reduced prevalence of BPD, which is frequently associated with less weight gain as a result of greater respiratory effort with greater energy expenditure.

Factors affecting total protein and lactoferrin in human milk

The aim of this study was to investigate factors affecting total, true protein and lactoferrin (Lf) concentrations in human milk (HM) and to evaluate the changes in protein concentrations over the course of lactation (first to sixth month postpartum). HM samples were collected from exclusively breastfeeding mothers during six time periods (1-6 months postpartum); 198 breast milk samples were collected in total. The concentrations of total and true protein in HM were determined using the MIRIS human milk analyzer (HMA). The assessment of HM protein content was also performed in skim HM samples and quantified by bicinchoninic methods with the Bicinchoninic Acid Protein Assay Kit. In turn, Lf content in skim HM samples was determined by the enzyme-linked immunosorbent assay (ELISA) in accordance with a slightly modified procedure. In the first month of lactation total protein concentration was negatively correlated with maternal pre-pregnancy BMI (r = - 0.397; p = 0.022), whereas in the third month postpartum, positive correlation with maternal age was found (r = 0.399; p = 0.021). Considering Lf concentration, in the first month of lactation, it was positively correlated with baby's birth weight (r = 0.514; p = 0.002). In the next months (from second to sixth) no relationships between Lf concentration and maternal and infants' factors were observed. The concentration of protein and Lf in HM changes dynamically throughout lactation. Maternal and infant characteristics may impact the HM protein and Lf content, especially in the first month postpartum.

Secretory-IgA binding to intestinal microbiota attenuates inflammatory reactions as the intestinal barrier of preterm infants matures

Previous work has shown that Secretory-IgA (SIgA) binding to the intestinal microbiota is variable and may regulate host inflammatory bowel responses. Nevertheless, the impact of the SIgA functional binding to the microbiota remains largely unknown in preterm infants whose immature epithelial barriers make them particularly susceptible to inflammation. Here, we investigated SIgA binding to intestinal microbiota isolated from stools of preterm infants <33 weeks gestation with various levels of intestinal permeability. We found that SIgA binding to intestinal microbiota attenuates inflammatory reactions in preterm infants. We also observed a significant correlation between SIgA affinity to the microbiota and the infant's intestinal barrier maturation. Still, SIgA affinity was not associated with developing host defenses, such as the production of mucus and inflammatory calprotectin protein, but it depended on the microbiota shifts as the intestinal barrier matures. In conclusion, we reported an association between the SIgA functional binding to the microbiota and the maturity of the preterm infant's intestinal barrier, indicating that the pattern of SIgA coating is altered as the intestinal barrier matures.

High protein content in breast milk from South African mothers of preterm infants

AIM

Macronutrient and energy content of human milk are largely assumed for fortification practices. The aim was to explore macronutrient and energy content of transition and mature human milk from South African mothers of preterm infants with a birth weight <1800 g. Secondary objectives compared day to night milk; and explored associations with selected innate factors.

METHODS

In this single-centre, observational study macronutrient and energy content of day, night and mixed samples of transition (first 14 days of life) and mature (from Day 15 of life) human milk were analysed with mid-infrared spectroscopy.

RESULTS

In total, 116 samples (38 days; 37 night; 41 mixed) from 47 mothers were retained for statistical analysis. Mean true protein, carbohydrate, fat and energy content of mixed samples per 100 mL were 1.5 ± 0.4 g, 7.2 ± 0.7 g, 3.5 ± 0.9 g and 69.4 ± 9.9 kcal, respectively. Mixed transition milk (n = 9) had 1.9 ± 0.3 g protein and 67.4 ± 9.6 kcal and mixed mature milk (n = 32) 1.4 ± 0.4 g protein and 70.0 ± 10.1 kcal, per 100 mL.The protein content of transition (p = 0.004) and mature (p = 0.004) milk were significantly higher than published data. Transition milk: 1.5 g protein, 65 kcal; mature milk: 1.2 g protein, 72 kcal per 100 mL. Night samples had less fat (p = 0.014) and energy (p = 0.033) than day samples. With increasing day of life protein content declined (p = 0.003).

CONCLUSION

The protein content of human milk from South African mothers of preterm babies differs from published data and has implications for human milk fortification practises.

Effect of fortification on the osmolality of human milk

BACKGROUND

It is known that human milk fortifiers (HMF) increases osmolality of human milk (HM) but some aspects of fortification have not been deeply investigated. Our aim was to evaluate the effect of fortification on the osmolality of donor human milk (DHM) and mother's own milk (MOM) over 72 h of storage using two commercial fortifiers and medium-chain triglycerides (MCT) supplementation.

METHODS

Pasteurized DHM and unpasteurized preterm MOM were fortified with 4% PreNAN FM85, 4% PreNAN FM85 plus 2% MCT, or 4% Aptamil BMF. Osmolality was measured in unfortified DHM and MOM and, moreover, just after fortification (T₀), and after 6 (T₆), 24 (T₂₄) and 72 h (T₇₂) to determine the effect of mixing and storage.

RESULTS

Unfortified DHM and MOM did not show changes of osmolality. Fortification increased osmolality of DHM and MOM without changes during the study period, except for Aptamil BMF which increased osmolality of MOM. The addition of MCT to fortified human milk (FHM) did not affect its osmolality.

CONCLUSIONS

Changes of osmolality in the 72 h following fortification of both DHM and MOM did not exceed the safety values supporting the theoretically possibility of preparing 72 h volumes of FHM. Supplementation with MCT of FHM does not change osmolality suggesting that increasing energy intake in preterm infants via this approach is safe.

Protein and Immune Component Content of Donor Human Milk in Japan: Variation with Gestational and Postpartum Age

Donor human milk (DHM) is the second-best nutrition for preterm infants when their own mother's milk is unavailable. The nutrient content of human milk is influenced by various factors, including gestational and postpartum age, but there are no data regarding DHM composition in Japan. The aim of this study was to determine the protein and immune component content of DHM in Japan and to elucidate the effects of gestational and postpartum age on nutrient composition. From September 2021 to May 2022, 134 DHM samples were collected from 92 mothers of preterm and term infants. Protein concentrations in preterm DHM (n = 41) and term DHM (n = 93) were analyzed using a Miris Human Milk Analyzer. The concentrations of secretory immunoglobulin A (sIgA) and lactoferrin, major immune components, were measured using enzyme-linked immunosorbent assays. Preterm DHM exhibited higher protein content than term DHM (1.2 g/dL and 1.0 g/dL, respectively, p < 0.001), whereas sIgA content was higher in term DHM than in preterm DHM (110 μg/mL and 68.4 μg/mL, respectively, p < 0.001). Gestational age was negatively correlated with protein levels and positively correlated with sIgA and lactoferrin levels. Furthermore, a negative correlation was found between postpartum week and protein, sIgA, and lactoferrin concentrations. Our data suggest that gestational and postpartum age affects protein, sIgA, and lactoferrin concentrations in DHM. These results indicate the importance of nutritional analysis for the appropriate use of DHM in preterm infants.

Supplementation of mother's own milk with term versus preterm donor human milk: a randomized controlled trial

The purpose of this is to evaluate the effect of supplementation of enteral feed volume with preterm versus term donor human milk (DHM) on short-term physical growth in very low birth weight (VLBW) neonates. In this open-label, variable block-sized, superiority, randomized controlled trial with allocation concealment, VLBW neonates with insufficient volume of mother's own milk (MOM) were assigned to receive either preterm (n = 48) or term (n = 54) DHM till discharge. Preterm DHM was defined as the breast milk expressed within 28 days of delivery at ≤ 34 weeks of gestation. The primary outcome was days to regain birth weight. Maternal and neonatal demographic variables were comparable in the two study groups. Days to regain birth weight were significantly more in the preterm DHM group, 17.4 (7.7) vs 13.6 (7.2) days, mean difference (95% CI) being 3.74 (0.48-7.0) days, P = 0.02). The proportion of MOM use was 82% in preterm vs 91.1%, P = 0.03 in the term milk group. Duration of skin-to-skin contact was also significantly lower in the preterm vs term milk group, the median (IQR) was 4 (0, 6) vs 4 (2, 6) hours/day, P < 0.01. However, bronchopulmonary dysplasia was higher in the preterm milk group (13% vs. 4%, P = 0.17). The velocity of gain in weight was similar in the two groups from week 1-3 but higher in the term DHM supplementation group during the 4th week. Conclusion: Supplementing MOM with preterm DHM did not result in a faster regaining of birth weight. Trial registration: CTRI/2020/02/023569; Date: 17.02.2020.

Secretory immunoglobulin A in preterm infants: determination of normal values in breast milk and stool

BACKGROUND

IgA and its secretory form sIgA impact protection from infection and necrotising enterocolitis but little is known about quantities in preterm mums own milk (MOM) or infant stool, onset of endogenous production in the preterm gut, and what affects these.

METHODS

We measured by ELISA in MOM and stool from healthy preterm infants total IgA and sIgA longitudinally and additionally in MOM fresh, refrigerated, frozen, and after traversing feeding systems.

RESULTS

In 42 MOM (median gestation 26 weeks), we showed total IgA levels and sIgA were highest in colostrum, fell over 3 weeks, and were not impacted by gestation. Median IgA values matched previous term studies (700 mcg/ml). In MOM recipients stool IgA was detected in the first week, at around 30% of MOM quantities. Formula fed infants did not have detectable stool IgA until the third week. Levels of IgA and sIgA were approximately halved by handling processes.

CONCLUSIONS

MOM in the 3 weeks after preterm delivery contains the highest concentrations of IgA and sIgA. Endogenous production after preterm birth occurs from the 3 week meaning preterm infants are dependent on MOM for IgA which should be optimised. Routine NICU practices halve the amount available to the infant.

IMPACT

(Secretory) Immunoglobulin A (IgA) is present in colostrum of maternal milk from infants as preterm as 23-24 weeks gestational age, falling over the first 3 weeks to steady levels similar to term. Gestation at birth does not impact (secretory) IgA levels in breast milk. IgA is present in very preterm infant stools from maternal milk fed infants from the first week of life, but not in formula milk fed preterm infants until week three, suggesting endogenous production from this point. Refrigeration, freezing, and feeding via plastic tubing approximately halved the amount of IgA available.

Efficacy of Donated Milk in Early Nutrition of Preterm Infants: A Meta-Analysis

Background: Preterm birth is associated with an increased risk of many complications, which is a main public health problem worldwide with social and economic consequences. Human milk from breast feeding has been proved to be the optimal nutrition strategy for preterm infants when available. However, the lack of human milk from mothers makes formula widely used in clinical practice. In recent years, donated breast milk has gained popularity as an alternative choice which can provide human milk oligosaccharides and other bioactive substances. Objective: We aimed to conduct a systematic review and meta-analysis to evaluate the nutritional effects of donated breast milk on preterm infants compared with formula. Method: In the present study, we searched Medline, Web of Science, Embase, clinicaltrials.gov, the China national knowledge infrastructure, and the Cochrane central register of controlled trials for candidate randomized controlled trials (RCTs). Results: A total of 1390 patients were enrolled in 11 RCTs and meta-analysis results showed that donated breast milk is also more advantageous in reducing the incidence of necrotizing enterocolitis (NEC, RR = 0.67, 95% CI = 0.48 to 0.93, p = 0.02), reducing the duration of parenteral nutrition (MD = −2.39, 95% CI = −3.66 to −1.13, p = 0.0002) and the time of full enteral feeding (MD = −0.33, 95% CI = −3.23 to 2.57, p = 0.0002). In comparison, formula significantly promotes the growth of premature infants, including their weight gain (MD = −3.45, 95% CI = −3.68 to −3.21, p < 0.00001), head growth (MD = −0.07, 95% CI = −0.08 to −0.06, p < 0.00001) and body length (MD = −0.13, 95% CI = −0.15 to −0.11, p < 0.00001), and reduces the time it takes for premature infants to regain birth weight (MD = 6.60, 95% CI = 6.11 to 7.08, p < 0.00001. Conclusion: Compared with formula, donated breast milk could significantly reduce the incidence of NEC, the duration of parenteral nutrition, and the time of full enteral feeding. Adding fortifiers in donated milk could make it as effective as formula in promoting the physical growth of premature infants.

Natural Association of Lysozyme and Casein Micelles in Human Milk

Using reversed phase high-performance liquid chromatography with ultraviolet (UV) detection and electrospray ionization (ESI)-quadrupole time-of-flight mass spectrometry (RP-HPLC-UV-ESI-Q-TOF), the lysozyme content in the milk of 10 volunteering mothers was quantified, ranging from 29 to 96 μg/mL. Following ultracentifugation, it was found that the lysozyme in human milk, unlike other whey proteins, is mainly bound to casein micelles (ca. 75%). The enzymatic activity of human lysozyme, measured as lytic activity against cell walls of Micrococcus lysodeikticus, was similar for the micelle-bound and free protein, indicating that the micellar structure should not affect the antibacterial activity of lysozyme. The results indicate that lysozyme is an integral component of casein micelles in human milk.

Review of Preterm Human-Milk Nutrient Composition

BACKGROUND

The human milk-fed preterm infant is at risk for growth failure, micronutrient deficiencies, and neurocognitive delay. Although protective and better tolerated than formula, human milk alone cannot meet the high nutrient requirements of this population, and fortification is necessary. Clinicians use assumptions of preterm human-milk composition to determine the type and quantity of fortification.

OBJECTIVES

The objectives of this review were to identify evidence of macronutrient and micronutrient concentration in preterm human milk and to identify knowledge gaps regarding composition.

METHODS

PubMed and the Cumulative Index to Nursing and Allied Health Literature were used to identify original articles published between January 1950 and December 2019.

RESULTS

Twenty-seven articles were found containing original data on macronutrients and micronutrients. Most (67%) of the studies published after 2011 measured the macronutrients and included gestational ages from 28 to 36 weeks. Milk collection methods, experimental design, and analytical methods varied between studies. There are 15 countries represented in this review; all of the American studies (n = 7) were published from 1980 to 1984.

CONCLUSIONS

African American women, or women delivering before 28 weeks' gestation are not represented in the literature. Accurate and targeted human-milk fortification depends on comprehensive, complete, and representative human-milk nutrient data. We have aggregated all available preterm human-milk macronutrient and micronutrient data and reported trends associated with lactation stage and gestational age. This report can aid in the design of feeding plans that are appropriate for the gestational age of the preterm infant and the lactation stage of the breastmilk.

Nutrient composition of preterm mother's milk and factors that influence nutrient content

BACKGROUND

Breast milk feedings are the optimal feeding choice for premature infants. Clinicians depend on accurate nutrient profiles of the breast milk in order to make informed decisions regarding the need for nutrient supplementation. Existing data for nutrient composition of preterm breast milk are dated and not representative of the current population of women delivering prematurely in the United States.

OBJECTIVES

The purpose of this prospective, longitudinal, single-center observational study was to measure the macronutrient and micronutrient composition of breast milk expressed by mothers, including women who self-identify as black, delivering preterm infants at ≤33 completed weeks of gestation.

METHODS

We collected breast milk samples from mothers of preterm infants admitted to the neonatal intensive care unit at Augusta University Medical Center from January 2019 through November 2019. Mother's milk samples were collected on postpartum days 7, 14, 21, and 28 and analyzed for macronutrients (energy, fat, protein, and carbohydrates) and micronutrients (sodium, potassium, chloride, calcium, phosphorus, magnesium, vitamin D, and zinc).

RESULTS

Thirty-eight mothers, mean age 27 ± 5.1 y and majority black (66%), provided milk for the study. The mean estimated gestational age and birth weight were 28.2 ± 2.8 weeks of gestation and 1098 ± 347 g, respectively, with 42% of mothers in the cohort delivering before week 28 of pregnancy. Differences in protein, sodium, potassium, calcium, phosphorus, and zinc concentrations based on race, day, and milk volume were identified. Dilution effects for protein, sodium, chloride, and vitamin D concentrations over time were identified.

CONCLUSIONS

Our study is among the first to characterize breast milk composition from women who delivered extremely preterm infants and adds to the evidence that race, gestational age, and volume influence the composition of preterm mother's milk. These factors should be considered when designing mother's milk-based feeds for premature infants.

The Effects of Early Oropharyngeal Administration of Microdosed Colostrum on Feeding Status in Ventilated Extremely Low-Birth-Weight Infants

Background: For extremely low-birth-weight infants (ELBWIs), mechanical ventilation and total parenteral nutrition are generally required in the early stages and lose the protective effect of early gastrointestinal nutrition of colostrum. We conducted a prospective randomized controlled trial to explore the effectiveness of early colostrum oropharyngeal administration on the feeding status of ELBWIs on mechanical ventilation. Materials and Methods: We randomly divided mechanically ventilated ELBWIs into an intervention group and a control group. In the intervention group, we provided oropharyngeal administration of colostrum during mechanical ventilation. The first colostrum oropharyngeal administration ended within 24 hours of birth. In the control group, we gave colostrum only for gastrointestinal nutrition, and other interventions were the same as for the intervention group. We collected the 1st and 6th day of life airway secretions and urine specimens from both groups. We recorded feeding status, including corrected gestational age at onset of enteral nutrition, corrected gestational age of no gastric retention during feeding, corrected gestational age of full enteral nutrition, corrected gestational age of sucking began, and corrected gestational age of per oral feeding. We also recorded growth of body mass, the incidence of feeding intolerance, and necrotizing enterocolitis (NEC). Results: On the 6th day of life, concentrations of secretory immunoglobulin A, and lactoferrin in airway secretions and urine of the intervention group were significantly higher than those of the control group (p < 0.05). The intervention group showed younger corrected gestational age of no gastric retention during feeding, corrected gestational age of full enteral nutrition, the corrected gestational age of sucking began and per oral feeding than those in the control group (p < 0.05). The day of recovery to birth weight was earlier than those in the control group (p < 0.05). The rate of feeding intolerance and NEC incidence in the intervention group was significantly lower than in the control group (p < 0.05). Conclusions: Early oropharyngeal administration of colostrum improves immune function of the gastrointestinal tract and the systemic anti-infective capability in ELBWI on mechanical ventilation, promoting the maturity of gastrointestinal function, improving feeding condition, and reducing the risk of feeding intolerance and NEC.

Analysis of the composition and antioxidant status of breast milk in women giving birth prematurely and on time

Background

Breastfeeding with mother’s milk is the best form of nutrition not only for newborn babies, but especially for premature babies, due to the health benefits of taking human food.

Objectives

The aim of the study was to examine the basic composition, cortisol concentration and antioxidant status of breast milk samples from women giving birth before 37 weeks of pregnancy and comparing it with milk samples from women giving birth after 37 weeks of pregnancy.

Methods

The material for the study was milk taken from women giving birth before and after 37 weeks of pregnancy. The basic composition of breast milk was determined using a MIRIS analyzer, cortisol concentration in samples by an enzyme-linked immunosorbent test and their total antioxidant status was assessed by DPPH and FRAP methods.

Results

It has been shown that the concentration of cortisol in samples of human milk in the group of women giving birth before 37 weeks was 13.95 ng / ml [4,71–86,84], while in the group of women giving birth after week 37 of pregnancy—10.31 ng / ml [2.35-39-02] (p = 0.014), while% inhibition of DPPH was 65.46% and 58.30%, respectively (p = 0.014).

Conclusions

Milk from women giving birth prematurely is qualitatively different from the milk of women giving birth on time. The total antioxidant status of preterm milk is higher than term milk, which promotes the development of premature babies. Higher cortisol levels in samples from women giving birth before 37 weeks of pregnancy may stimulate the digestive system.

New Insights Into Microbiota Modulation-Based Nutritional Interventions for Neurodevelopmental Outcomes in Preterm Infants

Gut microbiota and the central nervous system have parallel developmental windows during pre and post-natal life. Increasing evidences suggest that intestinal dysbiosis in preterm infants predisposes the neonate to adverse neurological outcomes later in life. Understanding the link between gut microbiota colonization and brain development to tailor therapies aimed at optimizing initial colonization and microbiota development are promising strategies to warrant adequate brain development and enhance neurological outcomes in preterm infants. Breast-feeding has been associated with both adequate cognitive development and healthy microbiota in preterms. Infant formula are industrially produced substitutes for infant nutrition that do not completely recapitulate breast-feeding benefices and could be largely improved by the understanding of the role of breast milk components upon gut microbiota. In this review, we will first discuss the nutritional and bioactive component information on breast milk composition and its contribution to the assembly of the neonatal gut microbiota in preterms. We will then discuss the emerging pathways connecting the gut microbiota and brain development. Finally, we will discuss the promising microbiota modulation-based nutritional interventions (including probiotic and prebiotic supplementation of infant formula and maternal nutrition) for improving neurodevelopmental outcomes.

Human Milk and Brain Development in Infants

Human milk is considered the most advantageous source of nourishment for infants. Even though there is no ideal composition of human milk, it still contains a unique combination of components that contribute to brain development. The aim of this review is to provide an overview on the possible correlation of human milk with the neurodevelopment of infants, with a special emphasis on myelination and epigenetic modifications. Research in human milk is a rapidly expanding field and cutting-edge technologies might contribute to identify specific mechanisms underlying the beneficial effects on human milk on neurodevelopment.

The impact of donor breast milk on metabolic bone disease, postnatal growth, and neurodevelopmental outcomes at 18 months' corrected age

BACKGROUND

Preterm infants are at risk for metabolic bone disease (MBD). Analysis of donor breast milk (DBM) shows lower levels of macronutrients compared with mother's own milk (MOM). The purpose of this study was to investigate the prevalence of MBD, rate of postnatal growth, and long-term neurodevelopmental outcomes in infants fed predominantly MOM vs DBM.

METHODS

Retrospective observational study of infants born <1500g and <32 weeks at New York University Langone Health or Bellevue Hospital from January 2014 to January 2018. Infants were divided into two groups: those who received >70% of feeds with either MOM or DBM by 34 weeks' corrected age (CA). MBD was assessed using alkaline phosphatase (AlkPO4) levels and radiographic findings. Data was also collected on growth, feeding tolerance, and long-term neurodevelopmental outcomes.

RESULTS

A total of 210 infants were included (MOM =156 and DBM =54). The DBM group had higher AlkPO4 levels for the first 3 weeks of life (P < .01). Growth was similar between the groups, and both groups demonstrated catch-up growth after discharge. No difference was seen in feeding intolerance, incidence of necrotizing enterocolitis, or sepsis. The DBM group had lower cognitive (odds ratio [OR], 0.93 [0.88-0.98]; P < .01) and language (OR, 0.95 [0.90-0.99]; P < .01) scores at 18 months' CA.

CONCLUSION

Infants fed predominantly DBM had elevated AlkPO4 levels suggestive of MBD but did not develop osteopenia. Despite appropriate growth and comparable short-term outcomes, infants fed DBM had lower cognitive and language scores at 18 months' CA.

Maternal BMI is positively associated with human milk fat: a systematic review and meta-regression analysis

BACKGROUND

Lack of robust estimates of human-milk nutrient composition and influential maternal factors, such as body composition, are barriers to informing nutrition policies and programs.

OBJECTIVE

The objective was to understand the relation between maternal BMI and human-milk energy, fat, and/or total protein.

METHODS

Four electronic databases (MEDLINE, Embase, CINAHL, and Web of Science) were searched. Outcomes assessed were human-milk energy (kcal/L), fat (g/L), and total protein (g/L) from mothers 1 to 6 mo postpartum. Studies with data on maternal BMI or weight and height that quantified human-milk energy, fat, or protein between 1 and 6 mo postpartum were eligible. Random-effects meta-regression weighted by the inverse of the study-level SE was completed for each of the 3 outcomes. The certainty of evidence for each outcome was assessed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

RESULTS

A total of 11,373 titles and abstracts were identified, and after full-text screening, 69 articles of 66 studies were included. Meta-regression results showed a positive association between maternal BMI and human-milk fat (β: 0.56 g/L; 95% CI: 0.034, 1.1; P = 0.04; I2 = 93.7%, n = 63 datapoints). There was no significant association between maternal BMI and human-milk energy (β: 3.9 kcal/L; 95% CI: -1.6, 9.5; P = 0.16, I2 = 93.3%, n = 40 datapoints) or total protein (β: 0.13 g/L; 95% CI: -0.16, 0.41; P = 0.37, I2 = 99.1%, n = 40 datapoints). The certainty of evidence for human-milk energy was low and the certainty of evidence for fat and total protein was very low.

CONCLUSIONS

Meta-regression analysis of available literature suggested an association between maternal BMI and human-milk fat between 1 and 6 mo postpartum. Future studies are needed to confirm the relation between maternal BMI; variation in human-milk energy, fat, and protein content; and the implications for child growth and development. This review is registered with International Prospective Register of Systematic Reviews (PROSPERO 2018 CRD42018098808) at https://www.crd.york.ac.uk/prospero/.

Acute changes to breast milk composition following consumption of high-fat and high-sugar meals

Breast milk composition is influenced by habitual diet, yet little is known about the short-term effects of changes in maternal diet on breast milk macronutrient concentrations. Our aim was to determine the acute effect of increased consumption of sugar/fat on breast milk protein, lactose and lipids. Exclusively breastfeeding women (n = 9) were provided with a control, higher fat (+28 g fat) and higher sugar (+66 g sugar) diet over three separate days at least 1 week apart. Hourly breast milk samples were collected concurrently for the analysis of triglycerides, cholesterol, protein, and lactose concentrations. Breast milk triglycerides increased significantly following both the higher fat and sugar diet with a greater response to the higher sugar compared to control diet (mean differences of 3.05 g/dL ± 0.39 and 13.8 g/dL ± 0.39 in higher fat and sugar diets, respectively [P < 0.001]). Breast milk cholesterol concentrations increased most in response to the higher sugar diet (0.07 g/dL ± 0.005) compared to the control (0.04 g/dL) and the higher fat diet (0.05 g/dL) P < 0.005. Breast milk triglyceride and lactose concentrations increased (P < 0.001, P = 0.006), whereas protein decreased (p = 0.05) in response to the higher fat diet compared to the control. Independent of diet, there were significant variations in breast milk composition over the day; triglycerides and cholesterol concentrations were higher at end of day (P < 0.001), whereas protein and lactose concentrations peaked at Hour 10 (of 12) (P < 0.001). In conclusion, controlled short-term feeding to increase daily sugar/fat consumption altered breast milk triglycerides, cholesterol, protein and lactose. The variations observed in breast milk protein and lactose across the 12 h period is suggestive of a circadian rhythm.

Role of Human Milk Bioactives on Infants' Gut and Immune Health

Exclusive human milk feeding of the newborn is recommended during the first 6 months of life to promote optimal health outcomes during early life and beyond. Human milk contains a variety of bioactive factors such as hormones, cytokines, leukocytes, immunoglobulins, lactoferrin, lysozyme, stem cells, human milk oligosaccharides (HMOs), microbiota, and microRNAs. Recent findings highlighted the potential importance of adding HMOs into infant formula for their roles in enhancing host defense mechanisms in neonates. Therefore, understanding the roles of human milk bioactive factors on immune function is critical to build the scientific evidence base around breastfeeding recommendations, and to enhance positive health outcomes in formula fed infants through modifications to formulas. However, there are still knowledge gaps concerning the roles of different milk components, the interactions between the different components, and the mechanisms behind health outcomes are poorly understood. This review aims to show the current knowledge about HMOs, milk microbiota, immunoglobulins, lactoferrin, and milk microRNAs (miRNAs) and how these could have similar mechanisms of regulating gut and microbiota function. It will also highlight the knowledge gaps for future research.

Longitudinal changes in the bioactive proteins in human milk of the Chinese population: A systematic review

This systematic review aimed at investigating longitudinal changes in human milk bioactive protein concentrations in Chinese population. Both English and Chinese databases were searched. The data were pooled into six defined lactation stages. Weighted means of protein concentrations in each stage and the statistical significance of means of different lactation stages were calculated. The data of 11 bioactive proteins were retrieved. Concentrations of sIgA, IgM, and IgG decreased sharply during the first 14 days of lactation. The levels of α-lactalbumin, lactoferrin, and β-casein also decreased throughout lactation. Conversely, lysozyme levels increased over lactation. The changing patterns of the serum albumin, osteopontin, and bile salt-stimulated lipase (BSSL) were not conclusive. This study represents the most comprehensive summary of bioactive proteins in Chinese human milk. In the future, mass spectrometry-based analysis of human milk proteomics may be used to investigate the longitudinal changes of many more bioactive proteins.

Infrared analyzers for the measurement of breastmilk macronutrient content in the clinical setting

INTRODUCTION

There is growing interest in the possibility of measuring the macronutrient content of human milk. Several studies that intend to validate commercially available human milk analyzers have been published with inconsistent results. This review will focus on currently available, verified methodologies for analyzing macronutrients in human milk.

AREAS COVERED

A literature search was conducted in the PubMed database. Five milk analyzers were chosen to be included in this review: MIRIS (Uppsala, Sweden) (seven articles found), Calais (Cleveland, United States) (four articles), SpectraStar (Brookfield, United States) (four articles), MilkoScan (Hillerdo, Denmark) (two articles), and Delta LactoScope (Stockholm, Sweden) (one article). The following information was extracted from published manuscripts: measuring device, sample preparation, purpose of the study, type of macronutrients studied, results, and conclusions.

EXPERT OPINION

Infrared spectroscopy can be an accurate and reliable technology for assessing the macronutrient content of human milk, specifically crude protein, and total fat. However, an optimal handling of samples, the development of standardized quality-control protocols, and an improvement in calibration procedures are required before the full implementation of infrared technology in neonatal units.

The Effect of Prolonged Freezing and Holder Pasteurization on the Macronutrient and Bioactive Protein Compositions of Human Milk

Introduction: Human donor milk is widely used to feed premature and sick newborns when the milk of their own mothers is insufficient. All treatment processes involving human milk affect its composition. The aim of this study was to assess changes in the macronutrients and bioactive protein (lactoferrin and lysozyme) content in human milk caused by freezing and Holder pasteurization. Materials and Methods: Milk samples were collected from 42 mothers 14-16 days after delivery. Each sample was divided into two parts and tested twice for macronutrient content, once upon being freshly collected and again after freezing at -40°C, thawing and Holder pasteurization. The lysozyme and lactoferrin concentrations were first determined in the unpasteurized thawed human milk after it was stored frozen at -80°C for up to 10 months and again after Holder pasteurization. The macronutrient concentrations were determined by midinfrared spectrophotometry, and enzyme-linked immunosorbent assay was used to measure the lysozyme and lactoferrin concentrations. Results: Freezing and Holder pasteurization had no significant effects on the macronutrient concentrations. The mean lactoferrin content before and after pasteurization was 2.5 ± 1.07 and 0.03 ± 0.03 mg/mL, respectively (p < 0.001), and the lysozyme content was 19.57 ± 20.11 and 12.62 ± 14.14 μg/mL, respectively (p = 0.007). Conclusions: Freezing and Holder pasteurization did not decrease the nutritional value of human milk but caused considerable loss of lactoferrin and lysozyme. New methods for treating human milk are needed that ensure the destruction of pathogenic microorganisms while retaining the biological and nutritional value of the milk. The Clinical Trial Registration number: NCT04382989.

Comparison of Changes in Breast Milk Macronutrient Content During the First Month in Preterm and Term Infants

Purpose: This study aims to achieve a better understanding of the trend of maternal milk macronutrient levels by analyzing protein, lipid, carbohydrate, and energy content of the breast milk and investigate the possible confounders of macronutrient content during the first 4 weeks of lactation to meet the specific needs of babies, guide optimum fortification of maternal milk. Patients and Methods: Breast milk from 39 mothers who had delivered preterm infants and 21 mothers of term infants were collected longitudinally for the first 4 weeks of lactation. Fresh milk samples were obtained on day 3, 7, 14, and 28 of lactation. The samples are analyzed using mid-infrared milk analyzer (MIRIS Human Milk Analyzer, HMA; Miris AB, Uppsala, Sweden). Results: Colostral milk protein concentrations of mothers of both preterm and term infants were significantly higher and the protein content of the samples decreased in time, according to the week of lactation during the study period. In contrast, fat, carbohydrate, and energy content were lowest in the colostral milk in both groups. When preterm and term milks were compared, fat and carbohydrate levels on 28th day and energy levels on 14th and 28th days were significantly higher in term milks, whereas no difference in protein contents were observed between the two groups on each time period. Mode of delivery was found to have statistically significant correlation with protein content of the milk. Conclusion: This longitudinal study revealed significant changes in analyzed macronutrient contents of mother's milk over the first 4 week period.

A Review of the Immunomodulating Components of Maternal Breast Milk and Protection Against Necrotizing Enterocolitis

Breast milk contains immunomodulating components that are beneficial to newborns during maturation of their immune system. Human breast milk composition is influenced by an infant's gestational and chronological age, lactation stage, and the mother and infant's health status. Major immunologic components in human milk, such as secretory immunoglobulin A (IgA) and growth factors, have a known role in regulating gut barrier integrity and microbial colonization, which therefore protect against the development of a life-threatening gastrointestinal illness affecting newborn infants called necrotizing enterocolitis (NEC). Breast milk is a known protective factor in the prevention of NEC when compared with feeding with commercial formula. Breast milk supplements infants with human milk oligosaccharides, leukocytes, cytokines, nitric oxide, and growth factors that attenuate inflammatory responses and provide immunological defenses to reduce the incidence of NEC. This article aims to review the variety of immunomodulating components in breast milk that protect the infant from the development of NEC.

Human Milk Retains Important Immunologic Properties After Defatting

BACKGROUND

In neonatal chylothorax, thoracic lymphatic drainage is ineffective. The resultant effusions often require drainage, leading to a loss of immune components. Affected infants can be managed with formula or defatted human milk feedings low in long-chain triglycerides to decrease lymph production. We hypothesized that there is no significant difference in the immunological profile or antibacterial effect of full-fat and defatted human milk.

METHODS

Milk from lactating mothers was divided into 1 aliquot that was defatted via centrifugation with the full-fat aliquot as control. Macronutrient content was analyzed with mid-infrared spectroscopy. Flow cytometry was used to measure immune cell populations. Lactoferrin, lysozyme, immunoglobulin (Ig)A, and IgG values were determined using enzyme-linked immunosorbent assay. The antibacterial properties were determined by inoculating paired full-fat and defatted milk samples with Escherichia coli or Streptococcus pneumoniae bacteria and performing colony counts.

RESULTS

Compared with full-fat milk, defatted milk demonstrated decreased total energy and fat and increased carbohydrate concentrations. Defatted milk demonstrated a significant decrease in all immune cell populations. There was no difference in IgA, IgG, lysozyme, or lactoferrin concentrations. Both aliquots demonstrated equivalent growth inhibition of E. coli and S. pneumoniae.

CONCLUSIONS

Unexpectedly, defatted human milk contained significantly less leukocytes than full-fat milk. IgA, IgG, lysozyme, and lactoferrin concentrations were preserved. The ability of defatted milk to inhibit bacterial growth was unaffected, suggesting that the antibacterial benefits of human milk remain after the defatting process. Further investigation regarding the clinical effect of leukocyte loss in defatted milk is warranted.

Longitudinal Analysis of Macronutrient Composition in Preterm and Term Human Milk: A Prospective Cohort Study

Background: Mother’s own milk is the optimal source of nutrients and provides numerous health advantages for mothers and infants. As they have supplementary nutritional needs, very preterm infants may require fortification of human milk (HM). Addressing HM composition and variations is essential to optimize HM fortification strategies for these vulnerable infants. Aims: To analyze and compare macronutrient composition in HM of mothers lactating very preterm (PT) (28 0/7 to 32 6/7 weeks of gestational age, GA) and term (T) infants (37 0/7 to 41 6/7 weeks of GA) over time, both at similar postnatal and postmenstrual ages, and to investigate other potential factors of variations. Methods: Milk samples from 27 mothers of the PT infants and 34 mothers of the T infants were collected longitudinally at 12 points in time during four months for the PT HM and eight points in time during two months for the T HM. Macronutrient composition (proteins, fat, and lactose) and energy were measured using a mid-infrared milk analyzer, corrected by bicinchoninic acid (BCA) assay for total protein content. Results: Analysis of 500 HM samples revealed large inter- and intra-subject variations in both groups. Proteins decreased from birth to four months in the PT and the T HM without significant differences at any postnatal time point, while it was lower around term equivalent age in PT HM. Lactose content remained stable and comparable over time. The PT HM contained significantly more fat and tended to be more caloric in the first two weeks of lactation, while the T HM revealed higher fat and higher energy content later during lactation (three to eight weeks). In both groups, male gender was associated with more fat and energy content. The gender association was stronger in the PT group, and it remained significant after adjustments. Conclusion: Longitudinal measurements of macronutrients compositions of the PT and the T HM showed only small differences at similar postnatal stages in our population. However, numerous differences exist at similar postmenstrual ages. Male gender seems to be associated with a higher content in fat, especially in the PT HM. This study provides original information on macronutrient composition and variations of HM, which is important to consider for the optimization of nutrition and growth of PT infants.

Oropharyngeal Mother's Milk: State of the Science and Influence on Necrotizing Enterocolitis

Oropharyngeal administration of mother's own milk-placing drops of milk directly onto the neonate's oral mucosa-may serve to (ex utero) mimic the protective effects of amniotic fluid for the extremely low birth weight infant; providing protection against necrotizing enterocolitis. This article presents current evidence to support biological plausibility for the use of OroPharyngeal Therapy with Mother's Own Milk (OPT-MOM) as an immunomodulatory therapy; an adjunct to enteral feeds of mother's milk administered via a nasogastric or orogastric tube. Current methods and techniques are reviewed, published evidence to guide clinical practice will be presented, and controversies in practice will be addressed.

Changes in the metabolite profile of breast milk over lactation stages and their relationship with dietary intake in Chinese women: HPLC-QTOFMS based metabolomic analysis

The aim of the present study was to comprehensively evaluate the changes in the metabolite profile of breast milk over lactation stages and their relationship with dietary intake in Chinese women by HPLC-QTOFMS based metabolomic analysis. The colostrum, transitional milk and mature milk of thirty healthy lactating women were collected for analysis. Eighty-four differential metabolites over lactation stages were identified, including 12 fatty acyls, 15 glycerolipids, 23 glycerophospholipids, 7 sphingolipids, 7 vitamins, 5 nucleotides-related metabolites, 2 amino acids, 1 amino acid derivate, 9 dipeptides, 1 steroid hormone, 1 energy-related metabolite and 1 amine. Partial least-squares regression analysis indicated that the metabolite profiles of the colostrum, transitional milk and mature milk have a strong relationship with dietary intake (R2 values were 0.92, 0.87 and 0.74, respectively). However, among the 84 differential metabolites over lactation stages, only two showed a strong relationship with dietary intake: 1,24,25-(OH)3 vitamin D3 was positively correlated with the dietary intake of meat and eggs, protein and fat; 11β-hydroxyprogesterone was negatively correlated with the dietary intake of fruit and carbohydrate. After adjusting for dietary intake, the variation trend of all the 84 differential metabolites over lactation stages remained unchanged. In conclusion, 84 differential metabolites in the breast milk of Chinese women over lactation stages were identified, and their variation trend was independent of dietary intake. These metabolites were partially different from those identified in previous metabolomic studies in the Western population. The present study is quite meaningful for understanding the variation of nutritional requirements in Chinese infants at different developmental stages and manufacturing optimal infant formulas for them.

Temporal changes of major protein concentrations in preterm and term human milk. A prospective cohort study

BACKGROUND

Proteins are major contributors to the beneficial effects of human milk (HM) on preterm infant health and development. Alpha-lactalbumin, lactoferrin, serum albumin and caseins represent approximately 85% of the total HM protein. The temporal changes of these proteins in preterm (PT) HM and its comparison with term (T) HM is poorly characterized.

AIMS

To quantify and compare the temporal changes of the major proteins in PT HM and T HM.

METHODS

HM was collected for 4 months postpartum at 12 time points for PT HM (gestational age 28 0/7-32 6/7 weeks; 280 samples) and for 2 months postpartum at 8 time points for T HM (gestational age 37 0/7-41 6/7 weeks; 220 samples). Proteins were measured with a micro-fluidic LabChip system.

RESULTS

Casein, alpha-lactalbumin and lactoferrin decreased with advancing stages of lactation in PT and T HM, whereas serum albumin remained stable. Only marginal differences between PT and T HM were observed for alpha-lactalbumin during postpartum weeks 3-5 and for serum albumin at the first week. However, a comparison of HM provided to preterm and term infants at the same postmenstrual ages revealed that alpha-lactalbumin contents were significantly lower in PT HM than in T HM during the 39-48 postmenstrual weeks.

CONCLUSIONS

This study provides comprehensive information of the longitudinal changes of major proteins in PT and T HM, and suggests limited availability of alpha-lactalbumin, a nutritionally important protein, in breastfed PT infants after reaching the term corrected age. This information may be important to optimize HM protein fortification, although its biological relevance needs to be confirmed by intervention studies.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov (NCT02052245), https://clinicaltrials.gov/ct2/show/NCT02052245.

Dose-response Relationship Between Donor Human Milk, Mother's Own Milk, Preterm Formula, and Neonatal Growth Outcomes

BACKGROUND

A dose-response relationship between proportions of donor human milk (DHM) intake and in-neonatal intensive care unit (in-NICU) growth rates, if any, remains poorly defined. Objective was to evaluate interrelationships between percentages of DHM, mother's own milk (MOM), and preterm formula (PF) intake and neonatal growth parameters at 36 weeks postmenstrual age or NICU discharge.

METHODS

Infants eligible for this single-center retrospective study were inborn at ≤32 weeks gestation or ≤1800 g, stayed in the NICU for ≥7 days, and received enteral nutrition consisting of human milk fortified with Enfamil human milk fortifier acidified liquid. Study exposures were defined as 10% increments in the total volumetric proportions of infant diet provided as MOM, DHM, or PF. Outcomes were growth parameters at 36 weeks postmenstrual age or NICU discharge. Multivariable linear regression modeled the adjusted additive effect of infant diet on individual growth parameters.

RESULTS

A total of 314 infants records were eligible for analysis. Using MOM as reference, the adjusted mean growth velocity for weight significantly decreased by 0.17 g · kg · day for every 10% increase in DHM intake, but did not vary with PF intake. The adjusted mean change in weight z score significantly decreased with increasing proportion of DHM intake but significantly improved with increasing PF intake. The adjusted mean head circumference velocity was significantly decreased by 0.01 cm/wk for every 10% increase in DHM intake, in reference to MOM, but did not vary with PF intake. Neither proportion of DHM nor PF intake was associated with length velocity.

CONCLUSIONS

When DHM and MOM are fortified interchangeably, preterm infants receiving incremental amounts of DHM are at increased risk of postnatal growth restriction. The dose-response relationship between DHM, MOM, and PF and long-term growth and neurodevelopmental outcomes warrants further research.

Better Control of Holder Pasteurization Results in Higher Retention of Human Milk Lactoferrin, IgA, and Lysozyme

Background: Holder pasteurization is commonly used in milk banks. We previously reported that the pattern of temperature and time may be different according to the pasteurizer used. Aim: The aim of our study was to assess the variances in pasteurization using two different devices: a standard pasteurizer (Past STD) and an optimized pasteurizer (Past OPTI). Methods: Immunoglobulin A (IgA), lactoferrin (LF), and lysozyme (LZ) content were assessed before and after pasteurization of 24 donor human milk samples. The impact of the pasteurization device was evaluated by testing 50- to 200-mL samples. Results: Mean temperature and duration of the plateau were 1.5°C lower and 11 min shorter, respectively, with Past OPTI vs. Past STD. The loss of IgA, LF, and LZ was 17.6, 5.6, and 9.8% lower, respectively, with Past OPTI than with Past STD. Conclusions: Accurate control of temperature enabled better preservation of IgA, LF, and LZ in donor milk. Holder pasteurization should be optimized, and new techniques proposed to treat donor milk should be compared with Holder pasteurization performed with a well-controlled device under realistic conditions.

Oropharyngeal Colostrum Administration in Very Low Birth Weight Infants: A Randomized Controlled Trial

OBJECTIVES

Studies have confirmed the safety of oropharyngeal administration of colostrum in very low birth weight infants. However, the effect of oropharyngeal administration of colostrum on immune system is inconclusive. This study aims to evaluate the effect of oropharyngeal administration of colostrum on secretory immunoglobulin A and lactoferrin in very low birth weight infants.

DESIGN

Randomized controlled trial.

SETTING

Forty-bedded neonatal ICU in a university children's hospital in the People's Republic of China.

PATIENTS

Very low birth weight infants were allocated to the study group (n = 32) and control group (n = 32).

INTERVENTION

The intervention was oropharyngeal administration of 0.2 mL of their mother's colostrum every 4 hours for 7 days. The control group received saline solution.

MEASUREMENTS AND MAIN RESULTS

Secretory immunoglobulin A and lactoferrin in urine and saliva were measured within 24 hours of life (baseline) and at 7 and 21 days. Primary outcomes were changes of secretory immunoglobulin A and lactoferrin in urine and saliva between baseline and at 7 and 21 days. Infant's clinical data were also collected during hospitalization. Change from baseline in lactoferrin in saliva at 7 days (5.18 ± 7.07 vs -1.74 ± 4.67 µg/mL; p < 0.001) and 21 days (5.31 ± 9.74 vs -1.17 ± 10.38 µg/mL; p = 0.02) shows statistic difference. No differences were found of lactoferrin in urine and also no differences of secretory immunoglobulin A in urine and saliva. There were also no differences between days to full enteral feeding, occurrence rate of clinical sepsis, proven sepsis, and necrotizing enterocolitis.

CONCLUSIONS

Oropharyngeal administration of colostrum can increases the level of lactoferrin in saliva in very low birth weight infants. No effect could be documented of secretory immunoglobulin A and lactoferrin in urine. Larger trials are needed to better describe the benefit of oropharyngeal administration of colostrum, if any, in very low birth weight infants.

"Bed Side" Human Milk Analysis in the Neonatal Intensive Care Unit: A Systematic Review

Human milk analyzers can measure macronutrient content in native breast milk to tailor adequate supplementation with fortifiers. This article reviews all studies using milk analyzers, including (i) evaluation of devices, (ii) the impact of different conditions on the macronutrient analysis of human milk, and (iii) clinical trials to improve growth. Results lack consistency, potentially due to systematic errors in the validation of the device, or pre-analytical sample preparation errors like homogenization. It is crucial to introduce good laboratory and clinical practice when using these devices; otherwise a non-validated clinical usage can severely affect growth outcomes of infants.

The Importance of Human Milk for Immunity in Preterm Infants

The immune system of preterm infants is immature, placing them at increased risk for serious immune-related complications. Human milk provides a variety of immune protective and immune maturation factors that are beneficial to the preterm infant's poorly developed immune system. The most studied immune components in human milk include antimicrobial proteins, maternal leukocytes, immunoglobulins, cytokines and chemokines, oligosaccharides, gangliosides, nucleotides, and long-chain polyunsaturated fatty acids. There is growing evidence that these components contribute to the lower incidence of immune-related conditions in the preterm infant. Therefore, provision of these components in human milk, donor milk, or formula may provide immunologic benefits.

Differences in Breast Milk Composition of HIV-Infected and HIV-Uninfected Mothers of Premature Infants: Effects of Antiretroviral Therapy

INTRODUCTION

A key strategy to prevent mother-to-child transmission of the human immunodeficiency virus (HIV) and to reduce infant morbidity and mortality includes providing the HIV-exposed premature infant with breast milk accompanied by dual anti-retroviral therapy (ART). The effects of HIV and ART on premature breast milk composition are largely unknown. The aim of the study was to assess and compare the breast milk composition of HIV-infected mothers receiving ART and HIV-uninfected mothers who gave birth to premature infants.

MATERIALS AND METHODS

Lactating HIV-infected women receiving ART (n = 38) and HIV-uninfected women (n = 36) with premature infants provided two breast milk samples on days 7 and 9, respectively, of lactation. Breast milk samples were analyzed for total energy, protein, carbohydrates, fat, phosphate, iron, zinc, and copper content.

RESULTS

Breast milk of HIV-infected women contained higher protein (1.95 versus 1.78 g/100 g; p = 0.04), fat (4.42 versus 3.49 g/100 g; p = 0.01), and copper (0.64 versus 0.56 mg/L; p = 0.02) levels; whereas carbohydrate (5.37 versus 6.67 g/100 g; p = 0.002) and zinc (5.26 versus 5.78 mg/L; p = 0.04) levels were lower compared with those of HIV-uninfected women. Zinc levels were significantly lower in HIV-infected women with early gestation periods, and the lowest levels were observed in women who received ART for ≤4 weeks (0.58 mg/L; p = 0.03). Total energy (78.22 versus 61.48 kCal/100 mL) and fat levels (5.39 versus 3.00 g/100 mL) were significantly higher in the late gestation period HIV-infected women. Copper levels (0.61 mg/L) were higher in the late gestation period women who received >4 weeks of ART exposure (p = 0.05).

CONCLUSION

Differences existed in the breast milk composition of HIV-infected women on ART compared with HIV-uninfected women. ART exposure period may influence breast milk composition.

Breast-Milk Cortisol and Cortisone Concentrations Follow the Diurnal Rhythm of Maternal Hypothalamus-Pituitary-Adrenal Axis Activity

BACKGROUND

Very preterm infants often receive donor milk from mothers who deliver at term, but its composition differs from that of their own mother's milk. Because breast-milk glucocorticoids can support developing neonates, we explored concentration variability within and between mothers.

OBJECTIVE

We hypothesized that breast-milk glucocorticoid concentrations would be higher after very preterm delivery [gestational age (GA) <32 wk; study 1] and would follow the diurnal rhythm of maternal adrenocortical activity (study 2).

METHODS

Study 1 assessed differences in milk cortisol, cortisone, and the cortisone-to-(cortisol+cortisone) ratio of mothers who delivered at (median) GA: 28.6 wk or at term weekly during the first month postpartum. Study 2 assessed variations in milk cortisol, cortisone, and the cortisone-to-(cortisol+cortisone) ratio over 24 h, and tested Pearson correlations between milk and salivary concentrations in mothers who delivered at term (median GA: 38.9 wk) during week 4 postpartum. In these studies, foremilk glucocorticoids were measured by liquid chromatography-tandem mass spectrometry. Associations of milk cortisol, milk cortisone, and the milk cortisone-to-(cortisol+cortisone) ratio with prematurity (study 1) or collection time (study 2) were studied with longitudinal data analyses.

RESULTS

In study 1, giving birth to a very preterm infant was associated with reductions in milk cortisol and cortisone concentrations of 50% (β: 0.50; 95% CI: 0.26, 0.99; P = 0.05) and 53% (β: 0.53; 95% CI: 0.30, 0.93; P = 0.03), respectively, when adjusted for collection time. In study 2, concentrations of milk cortisol and cortisone were associated with collection time (both P < 0.01), peaking at ∼0700. Milk and salivary concentrations of cortisol (r = 0.92, P < 0.01) and cortisone (r = 0.93, P < 0.01) as well as the cortisone-to-(cortisol+cortisone) ratio (r = 0.64, P < 0.01) were correlated with one another.

CONCLUSIONS

Breast-milk glucocorticoid concentrations follow the diurnal rhythm of maternal hypothalamus-pituitary-adrenal axis activity and are lower in mothers who deliver very preterm.

Factors affecting lactoferrin concentration in human milk: how much do we know?

Lactoferrin (LF) is a breast milk glycoprotein with antimicrobial and anti-inflammatory effects. Its beneficial properties in infants, especially in those born preterm, are currently being studied in clinical trials. However, the maternal and nursing infant factors that may affect LF concentration in breast milk are still not clear. We conducted a systematic review to investigate the factors that may affect the concentration of LF in breast milk. We used a 2-step approach to identify the eligible studies according to inclusion/exclusion criteria, and to determine which studies would be considered. We included 70 qualified articles from 29 countries with publication dates ranging from 1976 to 2015. We described the correlation between LF concentration in breast milk and lactation stage; 10 maternal factors, such as race, parity, among others; and 2 infant factors: infections and prematurity. Colostrum has the highest LF levels, but they decrease with days postpartum. No other factor has been consistently associated with LF concentration. A major limitation of the majority of the published studies is the small sample size and the different methods used to measure LF concentration. Therefore, there is a need for large, multicenter studies with standardized study design, sample collection, and LF measurement methods to identify clinically significant factors associated with LF expression in breast milk, which will help promote exclusive breastfeeding in preterm infants.

Calibration Adjustment of the Mid-infrared Analyzer for an Accurate Determination of the Macronutrient Composition of Human Milk

BACKGROUND

Human milk composition analysis seems essential to adapt human milk fortification for preterm neonates. The Miris human milk analyzer (HMA), based on mid-infrared methodology, is convenient for a unique determination of macronutrients. However, HMA measurements are not totally comparable with reference methods (RMs).

OBJECTIVE

The primary aim of this study was to compare HMA results with results from biochemical RMs for a large range of protein, fat, and carbohydrate contents and to establish a calibration adjustment.

METHODS

Human milk was fractionated in protein, fat, and skim milk by covering large ranges of protein (0-3 g/100 mL), fat (0-8 g/100 mL), and carbohydrate (5-8 g/100 mL). For each macronutrient, a calibration curve was plotted by linear regression using measurements obtained using HMA and RMs.

RESULTS

For fat, 53 measurements were performed, and the linear regression equation was HMA = 0.79RM + 0.28 (R(2) = 0.92). For true protein (29 measurements), the linear regression equation was HMA = 0.9RM + 0.23 (R(2) = 0.98). For carbohydrate (15 measurements), the linear regression equation was HMA = 0.59RM + 1.86 (R(2) = 0.95). A homogenization step with a disruptor coupled to a sonication step was necessary to obtain better accuracy of the measurements. Good repeatability (coefficient of variation < 7%) and reproducibility (coefficient of variation < 17%) were obtained after calibration adjustment.

CONCLUSION

New calibration curves were developed for the Miris HMA, allowing accurate measurements in large ranges of macronutrient content. This is necessary for reliable use of this device in individualizing nutrition for preterm newborns.

Levels of innate immune factors in preterm and term mothers' breast milk during the 1st month postpartum

There is a paucity of data on the effect of preterm birth on the immunological composition of breast milk throughout the different stages of lactation. We aimed to characterise the effects of preterm birth on the levels of immune factors in milk during the 1st month postpartum, to determine whether preterm milk is deficient in antimicrobial factors. Colostrum (days 2-5 postpartum), transitional milk (days 8-12) and mature milk (days 26-30) were collected from mothers of extremely preterm (<28 weeks of gestation, n 15), very preterm (28-<32 weeks of gestation, n 15), moderately preterm (32-<37 weeks of gestation, n 15) and term infants (37-41 weeks of gestation, n 15). Total protein, lactoferrin, secretory IgA, soluble CD14 receptor (sCD14), transforming growth factor-β2 (TGF-β2), α defensin 5 (HD5), β defensins 1 (HBD1) and 2, IL-6, IL-10, IL-13, interferon-γ, TNF-α and lysozyme (LZ) were quantified in milk. We examined the effects of lactation stage, gestational age, volume of milk expressed, mode of delivery, parity and maternal infection on milk immune factor concentrations using repeated-measures regression analysis. The concentrations of all factors except LZ and HD5 decreased over the 1st month postpartum. Extremely preterm mothers had significantly higher concentrations of HBD1 and TGF-β2 in colostrum than term mothers did. After controlling for other variables in regression analyses, preterm birth was associated with higher concentrations of HBD1, LZ and sCD14 in milk samples. In conclusion, preterm breast milk contains significantly higher concentrations of some immune proteins than term breast milk.