Components Of Human Milk Research Articles

Effects on Maternal Macronutrient Intake Towards Human Milk’s Fatty Acids Composition

While fatty acids found in human milk account for half of the energy consumed by exclusively breastfed infants, fatty acids such as monounsaturated fatty acids (MUFA) and long chain polyunsaturated fatty acids (LC-PUFA) plays critical roles in infant growth. Fatty acids components in human milk are vary widely accordance to the maternal diet during lactation but has not been sufficiently studied. The objective of this paper was to determine the correlation between maternal macronutrient intake with human milk’s fatty acids composition among exclusively breastfeeding mothers. A total of N=36 lactating mothers were recruited based on convenience sampling basis from Dengkil, Selangor and Kuantan, Pahang. A 24-hour dietary recall (24HR) was used to capture mother’s dietary intake in the past 24 hours. The human milk sample was collected in the next day morning after the diet recall and stored before proceeded to another fatty acids extraction and transesterification process namely Blight and Dyer method. The composition of fatty acids methyl esters was analyzed and quantified by a gas chromatography (Agilent 7890A), equipped with a flame ionization detector (FID) and Agilent Chromatography Workstation software. As overall, the most abundance fatty acids found was SFA ranged (81.90 to 97.7 %) followed with MUFA (2.3 to 18.1%), but PUFA was below detection limit (BDL). Result also indicated that palmitic, stearic, and oleic acids were the three major types of fatty acids determined from human milk. Correlational study also determined that, there was no significant correlation between the human milk’s SFA and MUFA with the same dietary intake and another macronutrient like carbohydrate and protein. Even though there was no significant correlation determined for the most composition, various pattern of correlation was found in the study. Human milk’s SFA only had a positive correlation with dietary carbohydrate but negative with the rest. Different pattern also showed for human milk’s MUFA which only negatively correlate with carbohydrate and fats while positive for the rest. Thus, overall, this fat composition is known to have higher variation in terms of concentration of its components compared to another macronutrient even within the same population. Aside from geographical considerations, maternal nationality and age have a substantial impact on the fatty acid composition of human milk.

A novel heat treatment protocol for human milk.

Human milk (HM) is the recommended nutrition for premature infants, but it may require processing to ensure microbial safety. The current standard is Holder pasteurisation (HoP), i.e. heating milk at 62.5 ± 0.5°C for 30 min, which eliminates bacteria but destroys heat labile bioactive HM components. We aimed to test an alternative thermal method, high-temperature short-time (HTST) pasteurisation using a modified Holder pasteurisation platform as this method has shown to preserve proteins in experimental HM flow pasteurisers. We analysed the ability of this batch process to eliminate bacterial species and to retain alkaline phosphatase, secretory immunoglobulin A and lactoferrin in HM. HTST at 81°C/5 s was as effective as HoP in bacterial count reduction while the retention of bioactive components was only improved at 62°C/5 s as compared to 72°C/5 s and HoP. HTST is a promising alternative to HoP but an optimal temperature-time combination needs to be determined for each technical platform separately.

The Results of Different Heating Temperatures on Activities of Bioactive Proteins in Human Milk.

The most utilized pasteurization method in donor human milk banks is Holder pasteurization (heating 62.5 °C for 30 min). However, many bioactive proteins are heat sensitive and are inactivated. To determine the results of a range of heating regimes on the activities of xanthine oxidase, lactoperoxidase and lysozyme, the concentrations of immunoglobulin A and lactoferrin, as well as bacterial inactivation. This prospective, cross-sectional, intervention study was designed to measure the influence of heating temperatures on bioactive components in donor human milk. Milk samples were processed at 40, 50, 55, 62.5, 75, 127 °C and the activities of the enzymes, and the concentration of immune proteins, were measured. No bacterial colonies were detectable, using standard culture methods, after heating above 50 ºC. All proteins studied retained over 60% concentrations or activities when the pasteurization temperature was 50 ºC or lower, while their concentrations or activities were lost at higher temperatures. For lactoferrin, the residual concentration was above 80% when heating temperature was under 55 °C, while only 20% remained after Holder pasteurization. Both xanthine oxidase and lactoperoxidase had little residual activity when temperatures were above Holder pasteurization. Lysozyme retained a greater proportion of residual activity than other proteins, following heating at all temperatures. The concentrations or activities of immune proteins and bioactive enzymes decreased when heated above 50 °C. The results of this study can be used to design temperature control guidance during alternative methods of pasteurization.

Dynamic change, influencing factors, and clinical impact of cellular components in human breast milk.

Numerous cellular components have been well demonstrated in human breast milk. However, little is known about their dynamic change, influencing factors, and potential clinical impacts on infants. Sixty and forty-five healthy mother-infant pairs were enrolled in the colostrum group and mature milk group, respectively. Participants' demographic and clinical information were collected by questionnaires, and the infants were followed up until 6 months after birth through telephone interview. Colostrum and mature milk were collected, and the percentage of various cell components were determined by flow cytometric analysis. The results showed that, the total cell numbers, and the percentages of some stem cells, including CD34+, CD117+, CD133+, CD90+, CD105+, and CD146+ cells, were different in colostrum and mature milk. Besides, participants' characteristics had influence on the cellular components. Finally, high-CD34+ cells in colostrum, as well as the high-CD133+ cells and low-CD105+ cells in mature milk were associated with a significantly increased risk of infantile eczema within their first 3 months after birth. Our data showed a dynamic change of cellular components, identified some of their influencing factors and their potential clinical impacts on infantile eczema, which helps to better understand the cellular components in human breast milk. Some stem cell markers were dynamically changed in human colostrum and mature milk. Different cellular components were shown to be influenced by different participants' characteristics. High percentage of CD34+ cells in colostrum, as well as high percentage of CD133+ cells and low percentage of CD105+ cells in mature milk, were associated with a significantly increased risk of infantile eczema within their first 3 months after birth. To our knowledge, this is the first study on the clinical impacts of stem cells on infantile diseases, which helps to give a better understanding of human breast milk.

Human Milk Oligosaccharide 2'-Fucosyllactose Modulates Local Viral Immune Defense by Supporting the Regulatory Functions of Intestinal Epithelial and Immune Cells.

Human milk contains bioactive components that provide protection against viral infections in early life. In particular, intestinal epithelial cells (IEC) have key regulatory roles in the prevention of enteric viral infections. Here we established an in vitro model to study the modulation of host responses against enteric viruses mimicked by poly I:C (pIC). The effects of 2′-fucosyllactose (2′FL), abundantly present in human milk, were studied on IEC and/or innate immune cells, and the subsequent functional response of the adaptive immune cells. IEC were pre-incubated with 2′FL and stimulated with naked or Lyovec™-complexed pIC (LV-pIC). Additionally, monocyte-derived dendritic cells (moDC) alone or in co-culture with IEC were stimulated with LV-pIC. Then, conditioned-moDC were co-cultured with naïve CD4+ T helper (Th)-cells. IEC stimulation with naked or LV-pIC promoted pro-inflammatory IL-8, CCL20, GROα and CXCL10 cytokine secretion. However, only exposure to LV-pIC additionally induced IFNβ, IFNλ1 and CCL5 secretion. Pre-incubation with 2′FL further increased pIC induced CCL20 secretion and LV-pIC induced CXCL10 secretion. LV-pIC-exposed IEC/moDC and moDC cultures showed increased secretion of IL-8, GROα, IFNλ1 and CXCL10, and in the presence of 2′FL galectin-4 and -9 were increased. The LV-pIC-exposed moDC showed a more pronounced secretion of CCL20, CXCL10 and CCL5. The moDC from IEC/moDC cultures did not drive T-cell development in moDC/T-cell cultures, while moDC directly exposed to LV-pIC secreted Th1 driving IL-12p70 and promoted IFNγ secretion by Th-cells. Hereby, a novel intestinal model was established to study mucosal host-defense upon a viral trigger. IEC may support intestinal homeostasis, regulating local viral defense which may be modulated by 2′FL. These results provide insights regarding the protective capacity of human milk components in early life.

Unveiling the influence of ultrasonic-assisted lipolysis: A pilot study of short-chain fatty acid profiling in human milk based on mass spectrometry

Short-chain fatty acids (SCFAs) were recently emerging components in human milk (HM), which might have positive effect on the growth and development of infants. Thus, rapid monitoring of SCFAs in HM, as well as their physiological roles, was vitally important. In this study, the complete profiling of HM SCFA was established in order to further understand the potential association of SCFA with human milk fat globule (HMFG) membranes. A new liquid-liquid extraction coupled with crucial pretreatment of ultrasonic-assisted lipolysis was used to break HMFG membranes efficiently, releasing valeric acid (VA) and hexanoic acid (HA) from their lipid-binding forms, while unchanged acetic acid (AA), propionic acid (PA) and butyric acid (BA). Moreover, an inter-platform comparison for the rapid semi-quantification of HM SCFAs, based on gas chromatography and liquid chromatography-mass spectrometry (GC–MS/LC-MS) was also performed. Our observations linked certain features of AA and HA, such as higher intensity under electron impact ionization than under electrospray ionization, to method performance characteristics. The concentrations of most SCFAs, obtained by GC-MS and LC-MS, showed consistent trends among individuals (p < 0.0001). This study was the first report on the comparative analysis of HM SCFA profiling, with all detectable components including AA, PA, BA, VA, and HA.

How Does Human Milk Protect Against Necrotizing Enterocolitis (NEC)? Targeted Validation and Time-Course Analysis of 35 Gene Responses as NEC-Signature in Fetal Intestinal Epithelial Cells.

Breastfeeding reduces the risk of necrotizing enterocolitis (NEC), one of the most common causes of morbidity and mortality in preterm infants. However, the molecular substrates by which human milk (HM) offers protection against NEC are not well known. Using fetal intestinal epithelial cells treated with known NEC aggravators, namely lipopolysaccharide (LPS) and platelet-activating factor (PAF), we mapped the time-course of changes in targeted expression analysis of 35 NEC-associated genes, so-called the NEC signature. We found, first, that HM treatment fully rescued LPS/PAF-induced fetal intestinal cell death at 12 and 24 h (n = 5). Differential gene expression and bioinformatics revealed that HM did not mitigate inflammatory and cell death signals, but instead promoted cell proliferation and stress response pathways to mitigate LPS/PAF-induced inflammatory cell death. From this, epidermal growth factor (EGF) synthesis emerged as the central player in rescue of the fetal intestinal cell death. Functional validation was supported by reversal of the cellular rescue by HM following EGF knockdown by small interfering RNA. In conclusion, this study suggests that HM might offer protection against NEC through enhancing intestinal EGF production to rescue the inflammatory cell death. Future studies are warranted to verify these HM molecular protective effects in NEC models in vivo. The findings reported herein also support future research avenues to discover new therapeutics to boost intrinsic EGF production in the injured intestinal tissues in neonates with NEC, for example, by bioactive components in human milk, natural compounds, or small molecules.

Breastfeeding: Importance in Early Development of the Immune System and Long-term Health

Breastfeeding supplies the baby and infant with unparalleled natural nutrients. Human breast milk also has several antimicrobial agents and may influence immune system development, as evidenced by prior research on newborn immunisation response and thymus gland development. Human milk is a dynamic supply of nutrients and bioactive ingredients and promotes the healthy growth and development of the human newborn. Infants are more susceptible to infection because their developing immune systems have a number of weaknesses. This review focuses on the direct effect of human milk on innate immunity in infants. Numerous new studies have made the multi-functionality of the bioactive components of human milk very clear. Our knowledge of the potential positive effects of human milk on infants has increased. These effects are not achievable with milk formulae. Human milk contains antimicrobial proteins and peptides that have a broader involvement in innate immune defence than previously thought. A complex combination of the anti-inflammatory and antioxidative substances that human milk supplies to the intestine results in a special environment of improved immune defence with reduced inflammation.

In silico analysis of the human milk oligosaccharide glycome reveals key enzymes of their biosynthesis

Human milk oligosaccharides (HMOs) form the third most abundant component of human milk and are known to convey several benefits to the neonate, including protection from viral and bacterial pathogens, training of the immune system, and influencing the gut microbiome. As HMO production during lactation is driven by enzymes that are common to other glycosylation processes, we adapted a model of mucin-type GalNAc-linked glycosylation enzymes to act on free lactose. We identified a subset of 11 enzyme activities that can account for 206 of 226 distinct HMOs isolated from human milk and constructed a biosynthetic reaction network that identifies 5 new core HMO structures. A comparison of monosaccharide compositions demonstrated that the model was able to discriminate between two possible groups of intermediates between major subnetworks, and to assign possible structures to several previously uncharacterised HMOs. The effect of enzyme knockouts is presented, identifying β-1,4-galactosyltransferase and β-1,3-N-acetylglucosaminyltransferase as key enzyme activities involved in the generation of the observed HMO glycosylation patterns. The model also provides a synthesis chassis for the most common HMOs found in lactating mothers.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects.

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant’s early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

Compositional Differences between Preterm Milk of Different Gestational Ages with the Term Milk: A Comparative Lipidomic Study by LC‐MS/MS

AbstractHuman milk lipids have important biological effects on recipient infants. The objective of this study is to comprehensively describe lipidomic differences between preterm milk of different gestational ages and term milk over the course of lactation. Colostrum (&lt;5 d postpartum, n = 20 for very preterm [VPT], n = 20 for moderately preterm [MPT] and n = 30 for full‐term [FT]) and mature milk (at four weeks postpartum, n = 11 for extremely preterm [EPT], n = 23 for VPT, n = 21 for MPT, and n = 25 for FT) are collected from 88 mothers who had delivered premature babies and 39 who had delivered term infants. It is found that the relative abundance of 10 out of 43 lipid subclasses are persistently higher in preterm milk than in term milk over the course of lactation. Diacylglycerol and fatty acid ester of hydroxyl fatty acid (FAHFA) lipid classes contribute most to the differences. The ten individual lipid species differing most significantly between VPT and FT colostrum are mainly part of the phosphatidylethanolamine and diacylglycerol groups. Levels of lipid species from the FAHFA class are significantly higher in both EPT and VPT mature milk than in their FT counterpart. The lipids in preterm and term milk show substantial differences, which may be critical for postnatal growth.Practical applications: These findings expand the current understanding of lipid components in human milk and provide important laboratory data for the future management of infant feeding, particularly of fragile, high risk EPT and VPT infants.

Impact of bovine lactoferrin fortification on pathogenic organisms to attenuate the risk of infection for infants

Cronobacter and Pseudomonas spp. are pathogenic organisms that are associated with neonatal morbidities such as bacteremia, sepsis, necrotizing enterocolitis (NEC), and infant meningitis. Lactoferrin (Lf) is a known bactericidal component of fresh human milk. Infants receiving formula or pasteurized donor milk however may not be receiving lactoferrin at same concentration as mother's own milk, so it is beneficial to understand an exogenous role for dairy bovine lactoferrin (bLf). Our aim was to investigate the potential for bLf to provide a novel way to inhibit the growth of these harmful organisms in infant feeding. Subinhibitory doses, Disc-diffusion assay, Minimum Inhibitory Concentrations (MIC), Minimum Bactericidal Concentrations (MBC), and challenge experiments in powder formula were used to investigate the effects of bLf on sepsis-causing bacteria such as C. muytjensii (ATCC-51329), C. sakazakii (ATCC-12868), C. sakazakii (ATCC-9027), P. aeruginosa (ATCC-19429), and P. aeruginosa (ATCC-9027). MIC and MBC of bLf in the range of 12.5–31.25 μM were sufficient to achieve a 3 log reduction of Cronobacter in nutrient broth (P < 0.0001). Similarly, minimum concentrations of 43.75–118.75 μM bLf against Pseudomonas (P < 0.0001) were demonstrated. After bactericidal concentrations were determined, higher resistant strains such as C. sakazakii (ATCC-12868) and P. aeruginosa (ATCC-19429) were chosen as ideal candidates for the bLf supplementation challenge studies. The bLf reduced the C. sakazakii (ATCC-12868) by 3.3 log at 35 °C, 2.8 log at 23 °C, and 1.9 log at 4 °C (P < 0.0001), whereas P. aeruginosa (ATCC-19429) showed 2.4 log reduction at 35 °C, 2.8 log at 23 °C (P < 0.0001), and 1.8 log at 4 °C (P < 0.01). Results indicated that bLf could effectively inactivate the sepsis-causing organisms in reconstituted infant formula and in bacterial growth media. Fortification of infant formula with bLf may address the problems of spoilage/contamination issues and provide a safety measure for feeding infants without mother's own milk.

The cellular dynamics of early and transitional human breast milk

Abstract Breast milk (BM) is a complex fluid containing factors essential for infant nutrition and immunity. Breastfeeding has been shown to be protective against infections and other immune-mediated diseases during the lactation period and beyond in later childhood. This suggests that BM also imprints the neonatal immune system and influences long-term health. BM also contains populations of maternal-derived cells. Which factors in BM that are important for neonatal health and how they change during lactation have not been well-defined. In this study, we used a single-cell transcriptomic approach to identify and define cell types of early and transitional milk. We collected BM samples from mothers of infants 2–5 days (early milk) and 8–12 days (transitional milk) after delivery. We applied single-cell RNA sequencing on over 154,000 BM-derived cells. We identified 25 transcriptionally distinct populations of cells in the BM. As expected, the most abundant cells in BM were mammary epithelial cells and macrophages. Monocytes, T cells, dendritic cells, and neutrophils were also present and had a higher frequency in week 2, suggesting that some immune cells may remain abundant in the early days of lactation and slowly decline as milk matures. We also detected a small number of stem and progenitor, natural killer and B cells in the BM at a higher frequency in week 1. This work provides an atlas of the cellular component in human milk at two timepoints of lactation. In addition to cell identity and frequencies, we have also uncovered unique molecular pathways that are activated in BM cells. This work will lay the foundation for future studies of how these cells influence neonatal health. Supported by funding from Children's Mercy Kansas City

Thyroxine and Thyroid-Stimulating Hormone in Own Mother’s Milk, Donor Milk, and Infant Formula

Breastfeeding is widely supported in clinical and home practices, and it is known that different forms of infant feeding differ in hormone content. Thyroid hormones have essential physiological roles. In our study, we examined thyroid-stimulating hormone (TSH), thyroxine, and albumin levels in breast milk produced for term (n = 16) or preterm (n = 15) infants throughout the first 6 months of lactation. Moreover, we analyzed these components in donor human milk and in three different infant formulas. Term and preterm breast milk samples were collected monthly. The two groups had similar levels of TSH (18.4 ± 1.4 vs. 24.7 ± 2.9 nU/L), but term milk contained higher amounts of thyroxine (11,245.5 ± 73.8 vs. 671.6 ± 61.2 nmol/L) during the examination period. The albumin level was significantly higher in preterm breast milk than in term breast milk (328.6 ± 17.1 vs. 264.2 ± 6.8 mg/L). In preterm breast milk we detected downward trends in the levels of TSH (−30.2%) and thyroxine (−29.2%) in the 3rd through 6th month compared to the first 2 months of lactation. Microbiological safety of donor milk was ensured by Holder pasteurization (HoP). From the Breast Milk Collection Center of Pécs, Hungary, we enrolled 44 donor mothers into the study. HoP decreased TSH (−73.8%), thyroxine (−22.4%), and albumin (−20.9%) concentrations. Infant formulas used by the Neonatal Intensive Care Unit of the University of Pécs were found to not contain the investigated hormones, but their albumin levels were similar to the breast milk samples. The present study shows the lack of thyroid hormones in infant formulas compared to human milk and raises the question of whether formula-fed infants should be supplemented with thyroid hormones.

Human Milk Macronutrients and Bioactive Molecules and Development of Regional Fat Depots in Western Australian Infants during the First 12 Months of Lactation.

We investigated associations between intakes of human milk (HM) components (macronutrients and biologically active molecules) and regional fat depots development in healthy term infants (n = 20) across the first year of lactation. Infant limb (mid-arm and mid-thigh) lean and fat areas were assessed by ultrasound imaging at 2, 5, 9 and 12 months of age. Concentrations of HM total protein, whey protein, casein, adiponectin, leptin, lysozyme, lactoferrin, secretory IGA, total carbohydrates, lactose, HM oligosaccharides (total HMO, calculated) and infant 24-h milk intake were measured, and infant calculated daily intakes (CDI) of HM components were determined. This pilot study shows higher 24-h milk intake was associated with a larger mid-arm fat area (p = 0.024), higher breastfeeding frequency was associated with larger mid-arm (p = 0.008) and mid-thigh (p < 0.001) fat areas. Lysozyme (p = 0.001) and HMO CDI (p = 0.004) were time-dependently associated with the mid-arm fat area. Intakes of HM components and breastfeeding parameters may modulate infant limb fat depots development during the first year of age and potentially promote favorable developmental programming of infant body composition; however, further studies are needed to confirm these findings.

Identified human breast milk compositions effectively inhibit SARS-CoV-2 and variants infection and replication

SummaryThe global pandemic of COVID-19 caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection confers great threat to public health. Human breast milk is a complex nutritional composition to nourish infants and protect them from different kinds of infectious diseases including COVID-19. Here, we identified that lactoferrin (LF), mucin1 (MUC1), and α-lactalbumin (α-LA) from human breast milk inhibit SARS-CoV-2 infection using a SARS-CoV-2 pseudovirus system and transcription and replication-competent SARS-CoV-2 virus-like-particles (trVLP). In addition, LF and MUC1 inhibited multiple steps including viral attachment, entry, and postentry replication, whereas α-LA inhibited viral attachment and entry. Importantly, LF, MUC1, and α-LA possess potent antiviral activities toward variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617.1 (kappa). Taken together, our study provides evidence that human breast milk components (LF, MUC1, and α-LA) are promising antiviral and potential therapeutic candidates warranting further development for treating COVID-19.

Effects of High-Pressure Processing, UV-C Irradiation and Thermoultrasonication on Donor Human Milk Safety and Quality.

Holder pasteurization (HoP) is the current recommended treatment for donor human milk. Although this method inactivates microbial contaminants, it also negatively affects various milk components. High-pressure processing (HPP, 400, 500, and 600 MPa), ultraviolet-C irradiation (UV-C, 2,430, 3,645, and 4,863 J/L) and thermoultrasonication (TUS, 1,080 and 1,620 kJ/L) were investigated as alternatives to thermal pasteurization (HoP). We assessed the effects of these methods on microbiological safety, and on concentration and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, with LC-MS/MS-based proteomics and activity assays. HoP, HPP, TUS, and UV-C at 4863 J/L, achieved >5-log10 microbial reduction. Native protein levels and functionality showed the highest reduction following HoP, while no significant reduction was found after less intense HPP and all UV-C treatments. Immunoglobulin A, lactoferrin, and lysozyme contents were also preserved after low intensity TUS, but bile salt-stimulated lipase activity was significantly reduced. This study demonstrated that HPP and UV-C may be considered as suitable alternatives to HoP, since they were able to ensure sufficient microbial inactivation while at the same time better preserving the bioactive components of donor human milk. In summary, our results provide valuable insights regarding the evaluation and selection of suitable processing methods for donor human milk treatment, which may replace HoP in the future.

Preterm birth and human milk proteome: are we ready for individualized fortification?

Preterm birth is one of the most pressing clinical problems in obstetrics and neonatology worldwide. One of the most sophisticated components of human milk is the proteome and a better understanding of it can lead to precision guides for feeding preterm infants. In this review, we will examine recent research focused on the human milk proteome and individualized protein fortification of human milk. In both preterm and term birth, the protein content in mother's own milk dropped rapidly in the early postnatal period. Preterm milk had a higher protein content and contained different protein and endogenous peptide compositions compared with term milk. The peptides in gastrointestinal fluids of preterm infants still need further investigation. Individualized fortification is more superior to standard fortification, but it only focuses on the total protein amount. There is no data concerning the composition and posttranslational modifications of proteins and endogenous peptides with fortification and their longterm effects. Comprehensive identification and characterization of the human milk proteome have led to the targeted breast milk fortification theory of preterm infant feeding and has also been enriched by clinical trials. However, to achieve fortification of key proteins and/or endogenous peptides, as standard clinical practice, requires additional studies. Future research should explore the long-term effect of protein fortification and pay more attention to quality rather than quantity in relation to infant body composition and growth outcomes.

Analysing the protection from respiratory tract infections and allergic diseases early in life by human milk components: the PRIMA birth cohort

BackgroundMany studies support the protective effect of breastfeeding on respiratory tract infections. Although infant formulas have been developed to provide adequate nutritional solutions, many components in human milk contributing to the protection of newborns and aiding immune development still need to be identified. In this paper we present the methodology of the “Protecting against Respiratory tract lnfections through human Milk Analysis” (PRIMA) cohort, which is an observational, prospective and multi-centre birth cohort aiming to identify novel functions of components in human milk that are protective against respiratory tract infections and allergic diseases early in life.MethodsFor the PRIMA human milk cohort we aim to recruit 1000 mother–child pairs in the first month postpartum. At one week, one, three, and six months after birth, fresh human milk samples will be collected and processed. In order to identify protective components, the level of pathogen specific antibodies, T cell composition, Human milk oligosaccharides, as well as extracellular vesicles (EVs) will be analysed, in the milk samples in relation to clinical data which are collected using two-weekly parental questionnaires. The primary outcome of this study is the number of parent-reported medically attended respiratory infections. Secondary outcomes that will be measured are physician diagnosed (respiratory) infections and allergies during the first year of life.DiscussionThe PRIMA human milk cohort will be a large prospective healthy birth cohort in which we will use an integrated, multidisciplinary approach to identify the longitudinal effect human milk components that play a role in preventing (respiratory) infections and allergies during the first year of life. Ultimately, we believe that this study will provide novel insights into immunomodulatory components in human milk. This may allow for optimizing formula feeding for all non-breastfed infants.

Biology of human milk oligosaccharides: From basic science to clinical evidence.

Human milk oligosaccharides (HMOs) have been researched by scientists for over 100 years, driven by the substantial evidence for the nutritional and health benefits of mother's milk. Yet research has truly bloomed during the last decade, thanks to progress in biotechnology, which has allowed the production of large amounts of bona fide HMOs. The availability of HMOs has been particularly crucial for the renewed interest in HMO research because of the low abundance or even absence of HMOs in farmed animal milk. This interest is reflected in the increasing number of original research publications and reviews on HMOs. Here, we provide an overview and critical discussion on structure–function relations of HMOs that highlight why they are such interesting and important components of human milk. Clinical observations in breastfed infants backed by basic research from animal models provide guidance as to what physiological roles for HMOs are to be expected. From an evidence‐based nutrition viewpoint, we discuss the current data supporting the clinical relevance of specific HMOs based on randomised placebo‐controlled clinical intervention trials in formula‐fed infants.