The human milk metabolome reveals diverse oligosaccharide profiles

Composition of linear and branched short-chain fatty acids in human milk and newborn feces: influence of perinatal and maternal factors

This research aimed to analyze the percentage of short-chain fatty acids (SCFAs) in human milk (HM) and newborn feces and to explore potential associations with factors such as maternal nutrition, age, biological sex, delivery mode, diet, and the type of HM. Gas chromatography was used to measure the percentage of SCFAs in colostrum (n = 23), transitional HM (n = 23), and mature HM (n = 92) and feces of newborn (n = 36) at day 30 postpartum. Anthropometry was also evaluated in the mother and the infant. The results showed that acetic acid was the most abundant in HM. The percentage of butyric acid and isovaleric acid was higher (p < 0.05) in the feces of newborns whose mothers were overweight/obese or were male, respectively, compared to newborns whose mothers were of normal weight or were female. The percentage of valeric acid was higher in the feces of newborns whose mothers were over 30 years old and who were delivered by C-section, compared to newborns whose mothers were 30 years old or younger and who were delivered vaginally. Inadequate intake of proteins, carbohydrates, and fiber was associated (p < 0.05) with lower acetic acid and higher butyric acid, higher propionic acid and lower butyric acid, and higher isovaleric acid percentage, respectively, in mature HM. The percentage of acetic acid was higher (p < 0.01) and that of propionic acid, butyric acid, isobutyric acid, and isovaleric acid was lower (p < 0.01) in colostrum compared to mature HM. The intake of lipids was associated with the percentage of butyric acid (β = -0.32, p = 0.01), and the percentage of propionic acid (β = 0.43, p < 0.01) was associated with carbohydrate intake. Overall, this study concluded that factors such as maternal nutritional status, diet, age, biological sex, and delivery mode were related to the composition of specific SCFAs in mature HM and newborn feces. Additionally, the percentage of SCFAs gradually decreased from colostrum to mature HM.

Evaluating Metabolic Profiling of Human Milk Using Biocrates MxP® QUANT 500 Assay

Background/Objectives: Metabolic profiling of human milk (HM) is indispensable for elucidating mother-milk-infant relationships. Methods: We evaluated the Biocrates MxP® Quant 500 assay for HM-targeted metabolomics (106 small molecules, 524 lipids) and analyzed in a feasibility test HM from apparently healthy Brazilian mothers (A: 2-8, B: 28-50, C: 88-119 days postpartum, ntotal = 25). Results: Of the 630 possible signatures detectable with this assay, 506 were above the limits of detection in an HM-pool (10 µL) used for assay evaluation, 12 of them above the upper limit of quantitation. Analyzing five different HM-pool volumes (2-20 µL) revealed acceptable linearity for 458 metabolites. Intraday accuracy of 80-120% was attained by 469 metabolites after spiking and for 342 after a 1:2 dilution. Analyzing HM from Brazilian mothers revealed significantly lower concentrations in colostrum vs. mature milk for many flow-injection analyses (FIA) and only a few LC-MS metabolites, including triglycerides, sphingomyelins, and phosphatidylcholines. Higher concentrations at the later lactation stages were found predominantly for amino acids and related compounds. Conclusions: The MxP Quant® 500 assay is a useful tool for HM metabolic profiling, minimizing analytical bias between matrices, and enhancing our ability to study milk as a biological system.

Associations of Maternal Salivary Cortisol and Psychological Symptoms With Human Milk's Microbiome Composition

OBJECTIVE

Human milk (HM) is considered the best source of infant nutrition with many benefits for the infant. However, pregnancy changes can lead to increased stress in some women, which might affect HM composition. Although studies have demonstrated a link between maternal psychopathology and child development, it remains unclear how maternal psychobiological changes can be intergenerationally transmitted. We aimed to investigate the associations of maternal stress, depressive symptoms, and anxiety symptoms with the HM microbiome; to analyze these parameters in relation to HM glucocorticoid concentrations; and to explore the influence of HM glucocorticoids on HM bacterial composition.

METHODS

One hundred women completed psychological questionnaires (e.g., EPDS, STAI, GAS) at 34-36 weeks' gestation and in the early postpartum period and provided saliva at 34-36 and 38 weeks' gestation. HM samples were collected in the early postpartum. Microbiota were analyzed using 16S rRNA amplicon sequencing.

RESULTS

Birth anxiety was negatively correlated with Alphaproteobacteria (τ = -0.20, FDR = 0.01), whereas in the postpartum period, anxiety symptoms were negatively correlated with different taxa. The sum of postpartum-related symptoms was linked to lower Propionibacteriales. Salivary cortisol AUCg at 34-36 weeks was negatively correlated with Stenotrophomonas (τ = -0.24, FDR = 0.05), whereas HM cortisol was positively correlated with Streptococcus mitis (τ = 0.26, FDR = 0.03) and Gemella haemolysans (τ = 0.24, FDR = 0.02). No associations emerged between psychobiological parameters and HM glucocorticoids.

CONCLUSIONS

Higher perinatal psychological symptoms and prenatal salivary cortisol AUCg were associated with lower relative abundances of different bacteria, whereas higher HM cortisol was linked to higher Gemella and Streptococcus. These findings suggest a negative association between high maternal psychobiological symptoms and relative abundances of the milk microbiota.

1H Nuclear Magnetic Resonance-Based Metabolomic Profiling and Comparison of Human Milk across Different Lactation Stages in Secretors and Nonsecretors: A Study of Chinese Lactating Women

BACKGROUND

Human milk oligosaccharides (HMOs) and other milk-derived metabolites are crucial for infant health, influencing gut microbiota and overall development.

OBJECTIVE

This study aimed to uncover insights into the variations of HMOs and non-HMO metabolites based on secretor (Se) status, lactation time, mode of delivery, and infant sex.

METHODS

An exploratory cross-sectional study was designed to compare the concentrations of HMOs and non-HMOs metabolites in milk samples from 129 lactating Chinese women within 1 y postpartum. Nuclear magnetic resonance analysis was employed for the identification and quantification of the metabolites. The metabolites measured were grouped into sugars, free amino acids, fatty acids, and metabolites related to energy metabolism. The influences of delivery mode and infant sex on milk metabolite composition were explored.

RESULTS

Uniform Manifold Approximation and Projection analysis of HMOs profiles revealed distinct clustering based on Se status, with significant differences in 2'-fucosyllactose (2'-FL) and 3-fucosyllactose (3-FL) concentrations observed between Se+ and Se- groups. A decreasing trend for 2'-FL and 6'-sialyllactose concentrations, along with an increase in 3-FL concentrations, was observed with increasing lactating period within 12 mo postpartum. Non-HMOs metabolite analysis indicated that Se status only affected glutamate concentrations. An increase in glutamine concentrations was observed 3-9 mo postpartum. A continuous increase in o-phosphocholine concentrations was noted in 12 mo postpartum, along with reductions in citrate and sn-glycero-phosphocholine concentrations. Delivery mode and infant sex did not affect both HMOs and non-HMOs concentrations.

CONCLUSIONS

Metabolomic analysis of human milk reveals significant variation of HMOs, but not in non-HMOs, based on Se status. Changes in certain HMOs and non-HMOs concentrations were also observed over the 1 y of lactation. Understanding how these metabolites change over time may influence recommendations for maternal diet, supplementation, and the timing of breastfeeding to ensure optimal nutrient delivery to the infant.

Comprehensive Targeted and Quantitative Profiling of the Human Milk Metabolome: Impact of Delivery Mode, Breastfeeding Practices, and Maternal Diet

SCOPE

Human milk (HM) is rich in bioactive compounds and essential nutrients. While research has focused on lipids, minerals, immune markers, microbiota, and oligosaccharides, specific metabolites are less studied. This study uses targeted metabolomics to identify and quantify metabolites in HM and explores the impact of perinatal and dietary factors on the metabolomic profile.

METHODS AND RESULTS

In a cross-sectional study of 123 healthy lactating women, HM samples were collected up to 1 month postpartum and analyzed using the Biocrates MxP Quant 500 kit. Maternal and neonatal clinical, anthropometric, and nutritional data were collected. A total of 432 metabolites were quantified and categorized into 20 groups. The metabolomic profiles formed three distinct clusters, primarily driven by triglyceride concentration differences. Docosahexaenoic acid (DHA) levels were higher in HM from mothers with vaginal delivery compared to C-section births and differences in hexoses were found between exclusive and mixed-feeding practices. Maternal diets rich in lipids and animal proteins were associated with elevated amino acids, sphingolipids, and glycosyl-ceramides.

CONCLUSION

The HM metabolome was grouped into three clusters influenced by delivery mode, lactation practices, and maternal diet. This comprehensive analysis opens new avenues to explore HM composition and offers valuable insights for future dietary interventions aimed at modulating HM.

The Influence of Maternal Lifestyle Factors on Human Breast Milk Microbial Composition: A Narrative Review

Human breast milk (HBM) is considered the gold standard for infant nutrition due to its optimal nutrient profile and complex composition of cellular and non-cellular components. Breastfeeding positively influences the newborn's gut microbiota and health, reducing the risk of conditions like gastrointestinal infections and chronic diseases (e.g., allergies, asthma, diabetes, and obesity). Research has revealed that HBM contains beneficial microbes that aid gut microbiota maturation through mechanisms like antimicrobial production and pathogen exclusion. The HBM microbiota composition can be affected by several factors, including gestational age, delivery mode, medical treatments, lactation stage, as well as maternal lifestyle habits (e.g., diet, physical activity, sleep quality, smoking, alcohol consumption, stress level). Particularly, lifestyle factors can play a significant role in shaping the HBM microbiota by directly modulating the microbial composition or influencing the maternal gut microbiota and influencing the HBM microbes through the enteromammary pathway. This narrative review of current findings summarized how maternal lifestyle influences HBM microbiota. While the influence of maternal diet on HBM microbiota is well-documented, indicating that dietary patterns, especially those rich in plant-based proteins and complex carbohydrates, can positively influence HBM microbiota, the impact of other lifestyle factors is poorly investigated. Maintaining a healthy lifestyle during pregnancy and breastfeeding is crucial for the health of both mother and baby. Understanding how maternal lifestyle factors influence microbial colonization of HBM, along with their interactions and impact, is key to developing new strategies that support the beneficial maturation of the infant's gut microbiota.

Effects of Human Milk Oligosaccharide 2'-Fucosyllactose Ingestion on Weight Loss and Markers of Health

BACKGROUND

2'-Fucosyllactose (2'-FL) is an oligosaccharide contained in human milk and possesses prebiotic and anti-inflammatory effects, which may alleviate skeletal muscle atrophy under caloric restriction. This study evaluated the impacts of 12 weeks of 2'-FL supplementation in conjunction with exercise (10,000 steps/day, 5 days/week) and energy-reduced (-300 kcals/day) dietary interventions on changes in body composition and health-related biomarkers.

METHODS

A total of 41 overweight and sedentary female and male participants (38.0 ± 13 years, 90.1 ± 15 kg, 31.6 ± 6.6 kg/m2, 36.9 ± 7% fat) took part in a randomized, double-blind, and placebo-controlled study. The participants underwent baseline assessments and were then assigned to ingest 3 g/day of a placebo (PLA) or Momstamin 2'-F while initiating the exercise and weight-loss program. Follow-up tests were performed after 6 and 12 weeks. Data were analyzed using general linear model statistics with repeated measures and mean changes from baseline values with 95% confidence intervals (CIs).

RESULTS

No group × time × sex interaction effects were observed, so group × time effects are reported. Participants in both groups saw comparable reductions in weight. However, those with 2'-FL demonstrated a significantly greater reduction in the percentage of body fat and less loss of the fat-free mass. Additionally, there was evidence that 2'-FL supplementation promoted more favorable changes in resting fat oxidation, peak aerobic capacity, IL-4, and platelet aggregation, with some minimal effects on the fermentation of short-chain fatty acids and monosaccharides in fecal samples. Moreover, participants' perceptions regarding some aspects of the functional capacity and ratings of the quality of life were improved, and the supplementation protocol was well tolerated, although a small, but significant, decrease in BMC was observed.

CONCLUSIONS

The results support contentions that dietary supplementation of 2'-FL (3 g/d) can promote fat loss and improve exercise- and diet-related markers of health and fitness in overweight sedentary individuals initiating an exercise and weight-loss program. Further research is needed to explore the potential health benefits of 2'-FL supplementation in both healthy and elderly individuals (Registered clinical trial #NCT06547801).

Establishing Reference Intakes for Creatine in Infants Aged 0 to 12 Months

Creatine is recognized as a conditionally essential nutrient in certain populations; however, there is a lack of established reference values across different life stages. Infants rely exclusively on dietary creatine from human milk for their first 6 months; evaluating creatine adequacy in this population can be estimated based on preliminary data regarding the intake needed to promote optimal growth. This special article explores creatine requirements for infants aged 0 to 12 months, presents a summary of creatine content in human milk, and proposes reference intakes for creatine in this population.

Untargeted metabolomic analysis of human milk from healthy mothers reveals drivers of metabolite variability

Understanding the human milk metabolome can help inform infant nutrition and health. Untargeted metabolomics was used to study breast milk from 31 healthy participants to assess the shared metabolites in milk from participants with various backgrounds and understand how different demographic, health, and environmental factors impact the milk metabolome. Breast milk samples were analyzed by four separate UPLC-MS/MS methods. Metabolite Set Enrichment Analysis was used to study the most and least variable metabolites. The associations between participant factors and the metabolome were assessed with redundancy analyses. Among all 31 participants and between each untargeted UPLC-MS/MS method, 731 metabolites were detected, of which 389 were shared among all participants. Of the shared metabolites, lactose was the least and lactobionate the most variable metabolite. In the biological super pathway analysis, xenobiotics were the most variable metabolites. Infant age, maternal age, number of live births, and pre-pregnancy BMI were associated with the milk metabolome. In conclusion, the most variable metabolites originate from environmental exposures while the well-conserved core metabolites are linked to cell metabolism or are crucial for infant nutrition and osmoregulation. Understanding the variability of the breast milk metabolome can help identify components that are crucial for infant nutrition, growth, and development.

Rapid method for quantitation of seven human milk oligosaccharides in infant formula and premix

As the evidence supporting the beneficial effects of human milk oligosaccharides (HMOs) grows, so does the commercial interest in their inclusion in infant formula products. This also requires analytical methods capable of their quantification from finished infant formula products as well as from premixed ingredients in some cases. The objective of the present study was the development and single-laboratory validation of a method that can be used for this purpose for seven HMOs: 2'-fucosyllactose (2'FL), 3-fucosyllactose (3FL), difucosyllactose (DFL), 3'-sialyllactose (3'SL), 6'-sialyllactose (6'SL), lacto-N-tetraose (LNT), and lacto-N-neotetraose (LNnT). The present method uses labeling by reductive amination, with 4-aminobenzoic acid ethyl ester (benzocaine) as the labeling reagent and picoline borane as the reducing agent, then applies HPLC separation with UV detection. The seven HMOs could be analyzed from infant formula and premix samples with recoveries between 91 and 108 %, relative standard deviations of 4.3 % or lower across all replicates, and limits of quantitation between 0.001 % and 0.004 % of powder sample by weight. The method was found to be rapid and reliable, with a runtime of only 14 min per injection, in contrast to other methods found in literature which typically use nearly or more than an hour. In addition, it uses instrumentation that's readily available in most analytical laboratories.

Unlocking the mysteries of milk oligosaccharides: Structure, metabolism, and function

Milk oligosaccharides (MOs), complex carbohydrates prevalent in human breast milk, play a vital role in infant nutrition. Serving as prebiotics, they inhibit pathogen adherence, modulate the immune system, and support newborn brain development. Notably, MOs demonstrate significant variations in concentration and composition, both across different species and within the same species. These characteristics of MOs lead to several compelling questions: (i) What distinct beneficial functions do MOs offer and how do the functions vary along with their structural differences? (ii) In what ways do MOs in human milk differ from those in other mammals, and what factors drive these unique profiles? (iii) What are the emerging applications of MOs, particularly in the context of their incorporation into infant formula? This review delves into the structural characteristics, quantification methods, and species-specific concentration differences of MOs. It highlights the critical role of human MOs in infant growth and their potential applications, providing substantial evidence to enhance infant health and development.

Comparison of canine colostrum and milk using a multi-omics approach

BACKGROUND

A mother's milk is considered the gold standard of nutrition in neonates and is a source of cytokines, immunoglobulins, growth factors, and other important components, yet little is known about the components of canine milk, specifically colostrum, and the knowledge related to its microbial and metabolic profiles is particularly underwhelming. In this study, we characterized canine colostrum and milk microbiota and metabolome for several breeds of dogs and examined profile shifts as milk matures in the first 8 days post-whelping.

RESULTS

Through untargeted metabolomics, we identified 63 named metabolites that were significantly differentially abundant between days 1 and 8 of lactation. Surprisingly, the microbial compositions of the colostrum and milk, characterized using 16S rRNA gene sequencing, were largely similar, with only two differentiating genera. The shifts observed, mainly increases in several sugars and amino sugars over time and shifts in amino acid metabolites, align with shifts observed in human milk samples and track with puppy development.

CONCLUSION

Like human milk, canine milk composition is dynamic, and shifts are well correlated with developing puppies' needs. Such a study of the metabolic profile of canine milk, and its relation to the microbial community, provides insights into the changing needs of the neonate, as well as the ideal nutrition profile for optimal functionality. This information will add to the existing knowledge base of canine milk composition with the prospect of creating a quality, tailored milk substitute or supplement for puppies.

A Stress Reduction Intervention for Lactating Mothers Alters Maternal Gut, Breast Milk, and Infant Gut Microbiomes: Data from a Randomized Controlled Trial

BACKGROUND

This secondary analysis of data from a randomized controlled trial (RCT) investigated how the maternal gut, breast milk, and infant gut microbiomes may contribute to the effects of a relaxation intervention, which reduced maternal stress and promoted infant weight gain.

METHODS

An RCT was undertaken in healthy Chinese primiparous mother-infant pairs (340/7-376/7gestation weeks). Mothers were randomly allocated to either the intervention group (IG, listening to relaxation meditation) or the control group (CG). Outcomes were the differences in microbiome composition and the diversity in the maternal gut, breast milk, and infant gut at 1 (baseline) and 8 weeks (post-intervention) between IG and CG, assessed using 16S rRNA gene amplicon sequencing of fecal and breastmilk samples.

RESULTS

In total, 38 mother-infant pairs were included in this analysis (IG = 19, CG = 19). The overall microbiome community structure in the maternal gut was significantly different between the IG and CG at 1 week, with the difference being more significant at 8 weeks (Bray-Curtis distance R2 = 0.04 vs. R2 = 0.13). Post-intervention, a significantly lower α-diversity was observed in IG breast milk (observed features: CG = 295 vs. IG = 255, p = 0.032); the Bifidobacterium genera presented a higher relative abundance. A significantly higher α-diversity was observed in IG infant gut (observed features: CG = 73 vs. IG = 113, p < 0.001).

CONCLUSIONS

The findings were consistent with the hypothesis that the microbiome might mediate observed relaxation intervention effects via gut-brain axis and entero-mammary pathways; but confirmation is required.

Brain-Derived Neurotrophic Factor as a Potential Mediator of the Beneficial Effects of Myo-Inositol Supplementation during Suckling in the Offspring of Gestational-Calorie-Restricted Rats

This study aims to investigate the potential mechanisms underlying the protective effects of myo-inositol (MI) supplementation during suckling against the detrimental effects of fetal energy restriction described in animal studies, particularly focusing on the potential connections with BDNF signaling. Oral physiological doses of MI or the vehicle were given daily to the offspring of control (CON) and 25%-calorie-restricted (CR) pregnant rats during suckling. The animals were weaned and then fed a standard diet until 5 months of age, when the diet was switched to a Western diet until 7 months of age. At 25 days and 7 months of age, the plasma BDNF levels and mRNA expression were analyzed in the hypothalamus and three adipose tissue depots. MI supplementation, especially in the context of gestational calorie restriction, promoted BDNF secretion and signaling at a juvenile age and in adulthood, which was more evident in the male offspring of the CR dams than in females. Moreover, the CR animals supplemented with MI exhibited a stimulated anorexigenic signaling pathway in the hypothalamus, along with improved peripheral glucose management and enhanced browning capacity. These findings suggest a novel connection between MI supplementation during suckling, BDNF signaling, and metabolic programming, providing insights into the mechanisms underlying the beneficial effects of MI during lactation.

Comparative Analysis of Free and Glycoconjugates Oligosaccharide Content in Milk from Different Species

Human milk is important for infant growth, and oligosaccharides are one of its main functional nutrients. To enable a systematic comparison of free oligosaccharide and glycoconjugate content in milk from different species, the phenol-sulfuric acid and resorcinol assays were combined to determine the content. Using real samples, the method revealed that human milk contained the highest amount of total, neutral (9.84 ± 0.31 g/L), and sialylated (3.21 ± 0.11 g/L) free oligosaccharides, followed by goat milk, with neutral (0.135 ± 0.015 g/L) and sialylated (0.192 ± 0.016 g/L) free oligosaccharides and at a distance by bovine and yak milk. The highest total glycoconjugate content was detected in yak milk (0.798 ± 0.011 g/L), followed by human, bovine, and goat milk. These findings suggest that goat milk is the best source of free oligosaccharides in infant formula and functional dairy products and yak milk is the best source of glycoconjugates.

Interaction and Metabolic Pathways: Elucidating the Role of Gut Microbiota in Gestational Diabetes Mellitus Pathogenesis

Gestational diabetes mellitus (GDM) is a complex metabolic condition during pregnancy with an intricate link to gut microbiota alterations. Throughout gestation, notable shifts in the gut microbial component occur. GDM is marked by significant dysbiosis, with a decline in beneficial taxa like Bifidobacterium and Lactobacillus and a surge in opportunistic taxa such as Enterococcus. These changes, detectable in the first trimester, hint as the potential early markers for GDM risk. Alongside these taxa shifts, microbial metabolic outputs, especially short-chain fatty acids and bile acids, are perturbed in GDM. These metabolites play pivotal roles in host glucose regulation, insulin responsiveness, and inflammation modulation, which are the key pathways disrupted in GDM. Moreover, maternal GDM status influences neonatal gut microbiota, indicating potential intergenerational health implications. With the advance of multi-omics approaches, a deeper understanding of the nuanced microbiota-host interactions via metabolites in GDM is emerging. The reviewed knowledge offers avenues for targeted microbiota-based interventions, holding promise for innovative strategies in GDM diagnosis, management, and prevention.

De novo biosynthesis of 2'-fucosyllactose by bioengineered Corynebacterium glutamicum

2'-Fucosyllactose (2'-FL) which is well-known human milk oligosaccharide was biotechnologically synthesized using engineered Corynebacterium glutamicum, a GRAS microbial workhorse. By construction of the complete de novo pathway for GDP-L-fucose supply and heterologous expression of Escherichia coli lactose permease and Helicobacter pylori α-1,2-fucosyltransferase, bioengineered C. glutamicum BCGW_TL successfully biosynthesized 0.25 g L-1 2'-FL from glucose. The additional genetic perturbations including the expression of a putative 2'-FL exporter and disruption of the chromosomal pfkA gene allowed C. glutamicum BCGW_cTTLEΔP to produce 2.5 g L-1 2'-FL batchwise. Finally, optimized fed-batch cultivation of the BCGW_cTTLEΔP using glucose, fructose, and lactose resulted in 21.5 g L-1 2'-FL production with a productivity of 0.12 g L-1 •h, which were more than 3.3 times higher value relative to the batch culture of the BCGW_TL. Conclusively, it would be a groundwork to adopt C. glutamicum for biotechnological production of other food additives including human milk oligosaccharides.

Glycerophosphocholine provision rescues Candida albicans growth and signaling phenotypes associated with phosphate limitation

IMPORTANCE

Candida albicans is the most commonly isolated species from patients suffering from invasive fungal disease. C. albicans is most commonly a commensal organism colonizing a variety of niches in the human host. The fungus must compete for resources with the host flora to acquire essential nutrients such as phosphate. Phosphate acquisition and homeostasis have been shown to play a key role in C. albicans virulence, with several genes involved in these processes being required for normal virulence and several being upregulated during infection. In addition to inorganic phosphate (Pi), C. albicans can utilize the lipid-derived metabolite glycerophosphocholine (GPC) as a phosphate source. As GPC is available within the human host, we examined the role of GPC in phosphate homeostasis in C. albicans. We find that GPC can substitute for Pi by many though not all criteria and is likely a relevant physiological phosphate source for C. albicans.

Impact of milk secretor status on the fecal metabolome and microbiota of breastfed infants

Maternal secretor status has been shown to be associated with the presence of specific fucosylated human milk oligosaccharides (HMOs), and the impact of maternal secretor status on infant gut microbiota measured through 16s sequencing has previously been reported. None of those studies have confirmed exclusive breastfeeding nor investigated the impact of maternal secretor status on gut microbial fermentation products. The present study focused on exclusively breastfed (EBF) Indonesian infants, with exclusive breastfeeding validated through the stable isotope deuterium oxide dose-to-mother (DTM) technique, and the impact of maternal secretor status on the infant fecal microbiome and metabolome. Maternal secretor status did not alter the within-community (alpha) diversity, between-community (beta) diversity, or the relative abundance of bacterial taxa at the genus level. However, infants fed milk from secretor (Se+) mothers exhibited a lower level of fecal succinate, amino acids and their derivatives, and a higher level of 1,2-propanediol when compared to infants fed milk from non-secretor (Se-) mothers. Interestingly, for infants consuming milk from Se+ mothers, there was a correlation between the relative abundance of Bifidobacterium and Streptococcus, and between each of these genera and fecal metabolites that was not observed in infants receiving milk from Se- mothers. Our findings indicate that the secretor status of the mother impacts the gut microbiome of the exclusively breastfed infant.

Viruses and Human Milk: Transmission or Protection?

Human milk (HM) is considered the best source of nutrition for infant growth and health. This nourishment is unique and changes constantly during lactation to adapt to the physiological needs of the developing infant. It is also recognized as a potential route of transmission of some viral pathogens although the presence of a virus in HM rarely leads to a disease in an infant. This intriguing paradox can be explained by considering the intrinsic antiviral properties of HM. In this comprehensive and schematically presented review, we have described what viruses have been detected in HM so far and what their potential transmission risk through breastfeeding is. We have provided a description of all the antiviral compounds of HM, along with an analysis of their demonstrated and hypothesized mechanisms of action. Finally, we have also analyzed the impact of HM pasteurization and storage methods on the detection and transmission of viruses, and on the antiviral compounds of HM. We have highlighted that there is currently a deep knowledge on the potential transmission of viral pathogens through breastfeeding and on the antiviral properties of HM. The current evidence suggests that, in most cases, it is unnecessarily to deprive an infant of this high-quality nourishment and that the continuation of breastfeeding is in the best interest of the infant and the mother.

Short-chain fatty acids levels in human milk are not affected by holder pasteurization and high hydrostatic pressure processing

Sterilized donor milk (DM) is frequently used for feeding preterm infants. To date, the effect of different modes of DM sterilization on short-chain fatty acids (SCFAs) remains unknown. We aimed to quantify SCFAs in DM samples after two types of milk sterilization: the Holder pasteurization (HoP) and a high hydrostatic pressure (HP) processing. Eight pooled DM samples were sterilized by HoP (62.5°C for 30 min) or processed by HP (350 MPa at 38°C). Raw DM was used as control. Six SCFAs were quantified by gas chromatography/mass spectrometry. Compared to raw milk, both HoP and HP treatment did not significantly modulate the concentration of acetate, butyrate, propionate and isovalerate in DM. Valerate and isobutyrate were undetectable in DM samples. In conclusion, both HoP and HP processing preserved milk SCFAs at their initial levels in raw human milk.

Dietary Fiber and Microbiota Metabolite Receptors Enhance Cognition and Alleviate Disease in the 5xFAD Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder with poorly understood etiology. AD has several similarities with other "Western lifestyle" inflammatory diseases, where the gut microbiome and immune pathways have been associated. Previously, we and others have noted the involvement of metabolite-sensing GPCRs and their ligands, short-chain fatty acids (SCFAs), in protection of numerous Western diseases in mouse models, such as Type I diabetes and hypertension. Depletion of GPR43, GPR41, or GPR109A accelerates disease, whereas high SCFA yielding diets protect in mouse models. Here, we extended the concept that metabolite-sensing receptors and SCFAs may be a more common protective mechanism against Western diseases by studying their role in AD pathogenesis in the 5xFAD mouse model. Both male and female mice were included. Depletion of GPR41 and GPR43 accelerated cognitive decline and impaired adult hippocampal neurogenesis in 5xFAD and WT mice. Lack of fiber/SCFAs accelerated a memory deficit, whereas diets supplemented with high acetate and butyrate (HAMSAB) delayed cognitive decline in 5xFAD mice. Fiber intake impacted on microglial morphology in WT mice and microglial clustering phenotype in 5xFAD mice. Lack of fiber impaired adult hippocampal neurogenesis in both W and AD mice. Finally, maternal dietary fiber intake significantly affects offspring's cognitive functions in 5xFAD mice and microglial transcriptome in both WT and 5xFAD mice, suggesting that SCFAs may exert their effect during pregnancy and lactation. Together, metabolite-sensing GPCRs and SCFAs are essential for protection against AD, and reveal a new strategy for disease prevention.Significance Statement Alzheimer's disease (AD) is one of the most common neurodegenerative diseases; currently, there is no cure for AD. In our study, short-chain fatty acids and metabolite receptors play an important role in cognitive function and pathology in AD mouse model as well as in WT mice. SCFAs also impact on microglia transcriptome, and immune cell recruitment. Out study indicates the potential of specialized diets (supplemented with high acetate and butyrate) releasing high amounts of SCFAs to protect against disease.

Real-world evidence study on tolerance and growth in infants fed an infant formula with two human milk oligosaccharides vs mixed fed and exclusively breastfed infants

INTRODUCTION

Human milk oligosaccharides (HMOs) are important components of human milk having diverse functions in the development of infants. Randomized controlled trials (RCTs) have demonstrated that infant formulas with the HMOs 2'-fucosyllactose (2'FL) and lacto-N-neotetraose (LNnT) are safe, well-tolerated, and support normal growth. This study aimed to generate real-world evidence (RWE) on growth and gastrointestinal (GI) tolerance in infants consuming a formula with 1 g/L 2'FL and 0.5 g/L LNnT, including a mixed feeding group not studied before in RCTs.

PARTICIPANTS AND METHODS

This 8-week open-label prospective multicenter study was conducted in Germany and Austria, and included groups of healthy, exclusively breastfed infants (BF), exclusively formula-fed infants (FF) who received the HMO-formula, and infants mixed fed with both HMO formula and human milk (MF). Co-primary outcomes were anthropometry and gastrointestinal tolerance via validated Infant Gastrointestinal Symptom Questionnaire (IGSQ). Secondary outcomes included formula satisfaction and adverse events (AEs).

RESULTS

One-hundred six infants completed the study (46 FF, 22 MF, and 38 BF). Mean anthropometric z-scores were comparable between groups and generally within ± 0.5 of WHO medians at week 8. IGSQ composite scores demonstrated good GI tolerance in all groups with no significant group differences at week 4 or 8. IGSQ composite scores in FF improved during the course of the study and parents provided high satisfaction ratings for the HMO-formula. Four potentially product-related AEs were reported in FF (no in MF).

CONCLUSIONS

In this RWE study examining an infant formula with HMOs, growth and GI tolerance outcomes were confirming the good tolerance and safety of this early feeding option previously reported in RCTs.

Intestinal mucus and their glycans: A habitat for thriving microbiota

The colon mucus layer is organized with an inner colon mucus layer that is impenetrable to bacteria and an outer mucus layer that is expanded to allow microbiota colonization. A major component of mucus is MUC2, a glycoprotein that is extensively decorated, especially with O-glycans. In the intestine, goblet cells are specialized in controlling glycosylation and making mucus. Some microbiota members are known to encode multiple proteins that are predicted to bind and/or cleave mucin glycans. The interactions between commensal microbiota and host mucins drive intestinal colonization, while at the same time, the microbiota can utilize the glycans on mucins and affect the colonic mucus properties. This review will examine this interaction between commensal microbes and intestinal mucins and discuss how this interplay affects health and disease.

Antibiotics augment the impact of iron deficiency on metabolism in a piglet model

Infancy and childhood represent a high-risk period for developing iron deficiency (ID) and is a period of increased susceptibility to infectious disease. Antibiotic use is high in children from low-, middle-, and high-income countries, and thus we sought to determine the impact of antibiotics in the context of ID. In this study, a piglet model was used to assess the impact of ID and antibiotics on systemic metabolism. ID was induced by withholding a ferrous sulfate injection after birth to piglets in the ID group and providing an iron deficient diet upon weaning on postnatal day (PD) 25. Antibiotics (gentamicin and spectinomycin) were administered on PD34-36 to a set of control (Con*+Abx) and ID piglets (ID+Abx) after weaning. Blood was analyzed on PD30 (before antibiotic administration) and PD43 (7 days after antibiotic administration). All ID piglets exhibited growth faltering and had lower hemoglobin and hematocrit compared to control (Con) and Con*+Abx throughout. The metabolome of ID piglets at weaning and sacrifice exhibited elevated markers of oxidative stress, ketosis, and ureagenesis compared to Con. The impact of antibiotics on Con*+Abx piglets did not result in significant changes to the serum metabolome 7-days after treatment; however, the impact of antibiotics on ID+Abx piglets resulted in the same metabolic changes observed in ID piglets, but with a greater magnitude when compared to Con. These results suggest that antibiotic administration in the context of ID exacerbates the negative metabolic impacts of ID and may have long lasting impacts on development.

Safety of 3-fucosyllactose (3-FL) produced by a derivative strain of Escherichia coli K-12 DH1 as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on 3-fucosyllactose (3-FL) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is mainly composed of the human-identical milk oligosaccharide (HiMO) 3-FL, but it also contains d-lactose, l-fucose, 3-fucosyllactulose and a small fraction of other related saccharides. The NF is produced by fermentation by a genetically modified strain (Escherichia coli K-12 DH1 MDO MAP1834) of E. coli K-12 DH1 (DSM 4235). The information provided on the manufacturing process, composition and specifications of the NF does not raise safety concerns. The applicant intends to add the NF to a variety of foods, including infant formula and follow-on formula, food for special medical purposes and food supplements (FS). The target population is the general population. The anticipated daily intake of 3-FL from both proposed and combined (authorised and proposed) uses at their respective maximum use levels in all population categories does not exceed the highest intake level of 3-FL from human milk in infants on a body weight basis. The intake of 3-FL in breastfed infants on a body weight basis is expected to be safe also for other population groups. The intake of other carbohydrate-type compounds structurally related to 3-FL is also considered of no safety concern. FS are not intended to be used if other foods with added 3-FL or human milk are consumed on the same day. The Panel concludes that the NF is safe under the proposed conditions of use.

Prebiotics to prevent necrotising enterocolitis in very preterm or very low birth weight infants

BACKGROUND

Dietary supplementation with prebiotic oligosaccharides to modulate the intestinal microbiome has been proposed as a strategy to reduce the risk of necrotising enterocolitis (NEC) and associated mortality and morbidity in very preterm or very low birth weight (VLBW) infants.

OBJECTIVES

To assess the benefits and harms of enteral supplementation with prebiotics (versus placebo or no treatment) for preventing NEC and associated morbidity and mortality in very preterm or VLBW infants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Maternity and Infant Care database and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), from the earliest records to July 2022. We searched clinical trials databases and conference proceedings, and examined the reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing prebiotics with placebo or no prebiotics in very preterm (< 32 weeks' gestation) or VLBW (< 1500 g) infants. The primary outcomes were NEC and all-cause mortality, and the secondary outcomes were late-onset invasive infection, duration of hospitalisation since birth, and neurodevelopmental impairment.

DATA COLLECTION AND ANALYSIS

Two review authors separately evaluated risk of bias of the trials, extracted data, and synthesised effect estimates using risk ratio (RR), risk difference (RD), and mean difference (MD), with associated 95% confidence intervals (CIs). The primary outcomes of interest were NEC and all-cause mortality; our secondary outcome measures were late-onset (> 48 hours after birth) invasive infection, duration of hospitalisation, and neurodevelopmental impairment. We used the GRADE approach to assess the level of certainty of the evidence.

MAIN RESULTS

We included seven trials in which a total of 705 infants participated. All the trials were small (mean sample size 100). Lack of clarity on methods to conceal allocation and mask caregivers or investigators were potential sources of bias in three of the trials. The studied prebiotics were fructo- and galacto-oligosaccharides, inulin, and lactulose, typically administered daily with enteral feeds during birth hospitalisation. Meta-analyses of data from seven trials (686 infants) suggest that prebiotics may result in little or no difference in NEC (RR 0.97, 95% CI 0.60 to 1.56; RD none fewer per 1000, 95% CI 50 fewer to 40 more; low-certainty evidence), all-cause mortality (RR 0.43, 95% CI 0.20 to 0.92; 40 per 1000 fewer, 95% CI 70 fewer to none fewer; low-certainty evidence), or late-onset invasive infection (RR 0.79, 95% CI 0.60 to 1.06; 50 per 1000 fewer, 95% CI 100 fewer to 10 more; low-certainty evidence) prior to hospital discharge. The certainty of this evidence is low because of concerns about the risk of bias in some trials and the imprecision of the effect size estimates. The data available from one trial provided only very low-certainty evidence about the effect of prebiotics on measures of neurodevelopmental impairment (Bayley Scales of Infant Development (BSID) Mental Development Index score < 85: RR 0.84, 95% CI 0.25 to 2.90; very low-certainty evidence; BSID Psychomotor Development Index score < 85: RR 0.24, 95% 0.03 to 2.00; very low-certainty evidence; cerebral palsy: RR 0.35, 95% CI 0.01 to 8.35; very low-certainty evidence).

AUTHORS' CONCLUSIONS

The available trial data provide low-certainty evidence about the effects of prebiotics on the risk of NEC, all-cause mortality before discharge, and invasive infection, and very low-certainty evidence about the effect on neurodevelopmental impairment for very preterm or VLBW infants. Our confidence in the effect estimates is limited; the true effects may be substantially different. Large, high-quality trials are needed to provide evidence of sufficient validity to inform policy and practice decisions.

Human Milk Lipids and Small Metabolites: Maternal and Microbial Origins

Although there has been limited application in the field to date, human milk omics research continues to gain traction. Human milk lipidomics and metabolomics research is particularly important, given the significance of milk lipids and metabolites for infant health. For researchers conducting compositional milk analyses, it is important to consider the origins of these compounds. The current review aims to provide a summary of the existing evidence on the sources of human milk lipids and small metabolites. Here, we describe five major sources of milk lipids and metabolites: de novo synthesis from mammary cells, production by the milk microbiota, dietary consumption, release from non-mammary tissue, and production by the gut microbiota. We synthesize the literature to provide evidence and understanding of these pathways in the context of mammary gland biology. We recommend future research focus areas to elucidate milk lipid and small metabolite synthesis and transport pathways. Better understanding of the origins of human milk lipids and metabolites is important to improve translation of milk omics research, particularly regarding the modulation of these important milk components to improve infant health outcomes.

Pistachio, Pomegranate and Olive Byproducts Added to Sheep Rations Change the Biofunctional Properties of Milk through the Milk Amino Acid Profile

This study was carried out to determine the effects of adding pistachio shell (PIS), pomegranate hull (POM), and olive pulp (OP) to the diet on milk amino acid and fatty acid parameters in Awassi sheep. In the study, 40 head of Awassi sheep, which gave birth at least twice, were used as animal material. Sheep were fed a control diet without added byproducts (CON), rations containing PIS, POM, and OP. Milk amino acid profile was determined by liquid chromatography-tandem mass spectrometry, milk fatty acid gas chromatography-flame ionization detection device. There was a dramatic reduction in alanine, citrulline, glutamine, glutamic acid, glycine, leucine, ornithine and alphaaminoadipic acid in the research groups. In the PIS group, argininosuccinic acid, gammaminobutyric acid, beta-alanine and sarcosine; In the POM group, asparagine, gammaminobutyric acid, beta-alanine, and taurine; In the OP group, a significant positive increase was found in terms of alanine, histidine, gammaminobutyric acid, and taurine amino acids. The applications in the study did not have a statistically significant effect on the ratio of short, medium and long chain fatty acids in milk (p>0.05). In the presented study, it was determined that PIS, POM, and OP, which were added to the sheep rations at a rate of 5%, caused significant changes in the milk amino acid profiles. In this change in milk amino acid profiles, the benefit-harm relationship should be considered.

Safety of 2'-fucosyllactose (2'-FL) produced by a derivative strain (APC199) of Corynebacterium glutamicumATCC 13032 as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on 2'-fucosyllactose (2'-FL) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is mainly composed of the human-identical milk oligosaccharide (HiMO) 2'-FL, but it also contains d-lactose, l-fucose, 3-fucosyllactose, difucosyllactose, d-glucose and d-galactose. The NF is produced by fermentation with a genetically modified strain (APC199) of Corynebacterium glutamicum ATCC 13032. 2'-FL, when chemically synthesised or produced by fermentation with derivative strains of Escherichia coli K-12 DH1 or E. coli BL21 (DE3), is already authorised and included in the EU list of NFs. This application refers to a change in the production process and specifications, while target population, conditions of use and consequently, the anticipated intake remain unchanged. The information provided on the identity, production process, composition and specifications of the NF does not raise safety concerns. The intake of other carbohydrate-type compounds structurally related to 2'-FL is also considered of no safety concern. In line with other milk oligosaccharides that are natural components of human milk, the safety assessment of this NF is mainly based on the comparison between the intake of breastfed infants and the estimated intake as NF. Given that the NF would be consumed at the same extent as the already authorised 2'-FL, the Panel considers that the consumption of the NF at the proposed uses and use levels does not raise safety concerns. The Panel concludes that the NF is safe under the proposed conditions of use.

Comparison of twelve human milk oligosaccharides in mature milk from different areas in China in the Chinese Human Milk Project (CHMP) study

Human milk oligosaccharides (HMOs) act as a vital role in the development of infant's gut microbiome and immune function. This study aimed to measure 12 oligosaccharides in milk from Chinese donors (n = 203), and evaluated the influences of multiple factors on the HMOs profiles. The results indicated that concentrations of 6'-sialyllactose were the highest among 12 oligosaccharides (2.31 ± 0.81 g/L). HMOs concentrations varied depending on geographical location. Latitude was observed to be related to concentrations of Lacto-N-neohexaose, lacto-N-fucopentaose III, 3'-sialyllactose (r = -0.67, r = +0.63 and r = +0.50, respectively). Environmental factors like seasons correlated with lacto-N-difucohexaose Ⅱ, Lacto-N-neohexaose and 2'-fucosyllactose (r = -0.47, r = -0.4, r = -0.35, respectively). Several HMOs concentrations were correlated with maternal diet. As a consequence, the HMOs profiles measured were influenced by geographical, environmental, maternal anthropometric as well as dietary factors.

2'-Fucosyllactose Remits Colitis-Induced Liver Oxygen Stress through the Gut-Liver-Metabolites Axis

Liver oxygen stress is one of the main extraintestinal manifestations of colitis and 5% of cases develop into a further liver injury and metabolic disease. 2′-fucosyllactose (2′-FL), a main member of human milk oligosaccharides (HMOs), has been found to exert efficient impacts on remitting colitis. However, whether 2′-FL exerts the function to alleviate colitis-induced liver injury and how 2′-FL influences the metabolism via regulating gut microbiota remain unknown. Herein, in our study, liver oxygen stress was measured by measuring liver weight and oxygen-stress-related indicators. Then, 16S full-length sequencing analysis and non-target metabolome in feces were performed to evaluate the overall responses of metabolites and intestinal bacteria after being treated with 2′-FL (400 mg/kg b.w.) in colitis mice. The results showed that, compared with the control group, the liver weight of colitis mice was significantly decreased by 18.30% (p < 0.05). After 2′-FL treatment, the liver weight was significantly increased by 12.65% compared with colitis mice (p < 0.05). Meanwhile, they exhibited higher levels of oxidation in liver tissue with decreasing total antioxidant capacity (T-AOC) (decreased by 17.15%) and glutathione (GSH) levels (dropped by 22.68%) and an increasing malondialdehyde (MDA) level (increased by 36.24%), and 2′-FL treatment could reverse those tendencies. Full-length 16S rRNA sequencing revealed that there were 39 species/genera differentially enriched in the control, dextran sulphate sodium (DSS), and DSS + 2′-FL groups. After treatment with 2′-FL, the intestinal metabolic patterns, especially glycometabolism and the lipid-metabolism-related process, in DSS mice were strikingly altered with 33 metabolites significantly down-regulated and 26 metabolites up-regulated. Further analysis found DSS induced a 40.01%, 41.12%, 43.81%, and 39.86% decline in acetic acid, propionic acid, butyric acid, and total short chain fatty acids (SCFAs) in colitis mice (all p < 0.05), respectively, while these were up-regulated to different degrees in the DSS + 2′-FL group. By co-analyzing the data of gut microbiota and metabolites, glycometabolism and lipid-metabolism-associated metabolites exhibited strong positive/negative relationships with Akkermansia_muciniphila (all p < 0.01) and Paraprevotella spp. (all p < 0.01), suggesting that the two species might play crucial roles in the process of 2′-FL alleviating colitis-induced liver oxygen stress. In conclusion, in the gut−liver−microbiotas axis, 2′-FL mediated in glucose and lipid-related metabolism and alleviated liver oxygen stress via regulating gut microbiota in the DSS-induced colitis model. The above results provide a new perspective to understand the probiotic function of 2′-FL.

Effects of lactic acid bacteria-fermented formula milk supplementation on ileal microbiota, transcriptomic profile, and mucosal immunity in weaned piglets

BACKGROUND

Lactic acid bacteria (LAB) participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites, which has numerous roles in the intestinal health-promoting of the consumer. However, information is lacking regarding the application prospect of LAB fermented milk in the animal industry. This study investigated the effects of lactic acid bacteria-fermented formula milk (LFM) on the growth performance, intestinal immunity, microbiota composition, and transcriptomic responses in weaned piglets. A total of 24 male weaned piglets were randomly divided into the control (CON) and LFM groups. Each group consisted of 6 replicates (cages) with 2 piglets per cage. Each piglet in the LFM group were supplemented with 80 mL LFM three times a day, while the CON group was treated with the same amount of drinking water.

RESULTS

LFM significantly increased the average daily gain of piglets over the entire 14 d (P < 0.01) and the average daily feed intake from 7 to 14 d (P < 0.05). Compared to the CON group, ileal goblet cell count, villus-crypt ratio, sIgA, and lactate concentrations in the LFM group were significantly increased (P < 0.05). Transcriptomic analysis of ileal mucosa identified 487 differentially expressed genes (DEGs) between two groups. Especially, DEGs involved in the intestinal immune network for IgA production pathways, such as polymeric immunoglobulin receptor (PIGR), were significantly up-regulated (P < 0.01) by LFM supplementation. Moreover, trefoil factor 2 (TFF2) in the LFM group, one of the DEGs involved in the secretory function of goblet cells, was also significantly up-regulated (P < 0.01). Sequencing of the 16S rRNA gene of microbiota demonstrated that LFM led to selective enrichment of lactate-producing and short-chain fatty acid (SCFA)-producing bacteria in the ileum, such as an increase in the relative abundance of Enterococcus (P = 0.09) and Acetitomaculum (P < 0.05).

CONCLUSIONS

LFM can improve intestinal health and immune tolerance, thus enhancing the growth performance of weaned piglets. The changes in microbiota and metabolites induced by LFM might mediate the regulation of the secretory function of goblet cells.

Multi-omic brain and behavioral correlates of cell-free fetal DNA methylation in macaque maternal obesity models

Maternal obesity during pregnancy is associated with neurodevelopmental disorder (NDD) risk. We utilized integrative multi-omics to examine maternal obesity effects on offspring neurodevelopment in rhesus macaques by comparison to lean controls and two interventions. Differentially methylated regions (DMRs) from longitudinal maternal blood-derived cell-free fetal DNA (cffDNA) significantly overlapped with DMRs from infant brain. The DMRs were enriched for neurodevelopmental functions, methylation-sensitive developmental transcription factor motifs, and human NDD DMRs identified from brain and placenta. Brain and cffDNA methylation levels from a large region overlapping mir-663 correlated with maternal obesity, metabolic and immune markers, and infant behavior. A DUX4 hippocampal co-methylation network correlated with maternal obesity, infant behavior, infant hippocampal lipidomic and metabolomic profiles, and maternal blood measurements of DUX4 cffDNA methylation, cytokines, and metabolites. We conclude that in this model, maternal obesity was associated with changes in the infant brain and behavior, and these differences were detectable in pregnancy through integrative analyses of cffDNA methylation with immune and metabolic factors.

Determining the metabolic fate of human milk oligosaccharides: it may just be more complex than you think?

Human milk oligosaccharides (HMOs) are a class of structurally diverse and complex unconjugated glycans present in breast milk, which act as selective substrates for several genera of select microbes and inhibit the colonisation of pathogenic bacteria. Yet, not all infants are breastfed, instead being fed with formula milks which may or may not contain HMOs. Currently, formula milks only possess two HMOs: 2'-fucosyllactose (2'FL) and lacto-N-neotetraose (LNnT), which have been suggested to be similarly effective as human breast milk in supporting age-related growth. However, the in vivo evidence regarding their ability to beneficially reduce respiratory infections along with altering the composition of an infant's microbiota is limited at best. Thus, this review will explore the concept of HMOs and their metabolic fate, and summarise previous in vitro and in vivo clinical data regarding HMOs, with specific regard to 2'FL and LNnT.

The Impact of Short-Chain Fatty Acids on Neonatal Regulatory T Cells

Over the first weeks of life, the neonatal gastrointestinal tract is rapidly colonised by a diverse range of microbial species that come to form the ‘gut microbiota’. Microbial colonisation of the neonatal gut is a well-established regulator of several physiological processes that contribute to immunological protection in postnatal life, including the development of the intestinal mucosa and adaptive immunity. However, the specific microbiota-derived signals that mediate these processes have not yet been fully characterised. Accumulating evidence suggests short-chain fatty acids (SCFAs), end-products of intestinal bacterial metabolism, as one of the key mediators of immune development in early life. Critical to neonatal health is the development of regulatory T (Treg) cells that promote and maintain immunological tolerance against self and innocuous antigens. Several studies have shown that SCFAs can induce the differentiation and expansion of Tregs but also mediate pathological effects in abnormal amounts. However, the exact mechanisms through which SCFAs regulate Treg development and pathologies in early life remain poorly defined. In this review, we summarise the current knowledge surrounding SCFAs and their potential impact on the neonatal immune system with a particular focus on Tregs, and the possible mechanisms through which SCFAs achieve their immune modulatory effect.

1H NMR Metabolomics of Chinese Human Milk at Different Stages of Lactation among Secretors and Non-Secretors

Human milk is an intricate, bioactive food promoting infant health. We studied the composition of human milk samples collected over an 8-month lactation using ¹H NMR metabolomics. A total of 72 human breast milk samples were collected from ten Chinese mothers at eight different time points. The concentrations of ten human milk oligosaccharides (HMOs), fucose and lactose were quantified. Six of the mothers were classified as Lewis-positive secretors (Se⁺Le⁺) and four as Lewis-positive non-secretors (Se⁻Le⁺) based on the levels of 2′-fucosyllactose (2′-FL), lacto-N-fucopentaose (LNFP) II, lactodifucotetraose (LDFT) and lacto-N-neotetraose (LNnT). Acetate, citrate, short/medium-chain fatty acids, glutamine and urea showed a time-dependent trend in relation to the stage of lactation. The concentrations of 2′-FL, 3-FL (3-fucosyllactose), 3′-SL (3′-sialyllactose), LDFT, LNFP I, LNFP II, LNFP III, LNnT, LNT (lacto-N-tetraose), and fucose were statistically different between secretors and non-secretors. A temporal difference of approximately 1–2 months between the development of non-secretor and secretor HMO profiles was shown. The results highlighted the importance of long-term breastfeeding, especially among non-secretors.

Dynamic Changes in the Human Milk Metabolome Over 25 Weeks of Lactation

Human milk (HM) provides essential nutrition for ensuring optimal infant growth and development postpartum. Metabolomics offers insight into the dynamic composition of HM. Studies have reported the impact of lactation stage, maternal genotype, and gestational age on HM metabolome. However, the majority of the studies have considered changes within the first month of lactation or sampled with large intervals. This leaves a gap in the knowledge of progressing variation in HM composition beyond the first month of lactation. The objective of this study was to investigate whether the HM metabolome from mothers with term deliveries varies beyond 1 month of lactation, during the period in which HM is considered fully mature. Human milk samples (n = 101) from 59 mothers were collected at weeks 1-2, 3-5, 7-9, and 20-25 postpartum and analyzed using 1H nuclear magnetic resonance spectroscopy. Several metabolites varied over lactation and exhibited dynamic changes between multiple time points. Higher levels of HM oligosaccharides, cis-aconitate, O-phosphocholine, O-acetylcarnitine, gluconate, and citric acid were observed in early lactation, whereas later in lactation, levels of lactose, 3-fucosyllactose, glutamine, glutamate, and short- and medium-chain fatty acids were increased. Notably, we demonstrate that the HM metabolome is dynamic during the period of maturity.

Bioactive compounds in mothers milk affecting offspring outcomes: A narrative review

BACKGROUND

Compared to the exhaustive study of transgenerational programming of obesity and diabetes through exposures in the prenatal period, postnatal programming mechanisms are understudied, including the potential role of breast milk composition linking maternal metabolic status (body mass index and diabetes) and offspring growth, metabolic health and future disease risk.

METHODS

This narrative review will principally focus on four emergent bioactive compounds [microRNA's (miRNA), lipokines/signalling lipids, small molecules/metabolites and fructose] that, until recently were not known to exist in breast milk. The objective of this narrative review is to integrate evidence across multiple fields of study that demonstrate the importance of these compositional elements of breast milk during lactation and the subsequent effect of breast milk components on the health of the infant.

RESULTS

Current knowledge on the presence of miRNA's, lipokines/signalling lipids, small molecules/metabolites and fructose in breast milk and their associations with infant outcomes is compelling, but far from resolved. Two themes emerge: (1) maternal metabolic phenotypes are associated with these bioactives and (2) though existing in milk at low concentrations, they are also associated with offspring growth and body composition.

CONCLUSION

Breast milk research is gaining momentum though we must remain focused on understanding how non-nutritive bioactive components are affected by the maternal phenotype, how they subsequently impact infant outcomes. Though early, there is evidence to suggest fructose is associated with fat mass in the 1st months of life whereas 12,13 diHOME (brown fat activator) and betaine are negatively associated with early adiposity and growth.

Safety of 3-fucosyllactose (3-FL) produced by a derivative strain of Escherichia coli BL21 (DE3) as a Novel Food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on 3-fucosyllactose (3-FL) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is mainly composed of the human-identical milk oligosaccharide (HiMO) 3-FL, but it also contains d-lactose, l-fucose, d-glucose and d-galactose, and a small fraction of other related saccharides. The NF is produced by fermentation with a genetically modified strain of Escherichia coli BL21 (DE3). The information provided on the manufacturing process, composition and specifications of the NF does not raise safety concerns. The applicant intends to add the NF to a variety of foods, including infant formula and follow-on formula, food for infants and young children, food for special medical purposes and food supplements. The target population is the general population. The anticipated daily intake of 3-FL from both proposed and combined (authorised and proposed) uses at their respective maximum use levels in all population categories does not exceed the highest intake level of 3-FL from human milk in infants on a body weight basis. The intake of 3-FL in breastfed infants on a body weight basis is expected to be safe also for other population groups. The intake of other carbohydrate-type compounds structurally related to 3-FL is also considered of no safety concern. Food supplements are not intended to be used if other foods with added 3-FL or human milk are consumed on the same day. The Panel concludes that the NF is safe under the proposed conditions of use.

Recent Advances on Lacto-N-neotetraose, a Commercially Added Human Milk Oligosaccharide in Infant Formula

Human milk oligosaccharides (HMOs) act as the important prebiotics and display many unique health effects for infants. Lacto-N-neotetraose (LNnT), an abundant HMO, attracts increasing attention because of its unique beneficial effects to infants and great commercial importance. It occurs in all groups of human milk, but the concentration generally decreases gradually with the lactation period. It has superior prebiotic property for infants, and its other health effects have also been verified, including being immunomodulatory, anti-inflammatory, preventing necrotizing enterocolitis, antiadhesive antimicrobials, antiviral activity, and promoting maturation of intestinal epithelial cells. Safety evaluation and clinical trial studies suggest that LNnT is safe and well-tolerant for infants. It has been commercially added as a functional ingredient in infant formula. LNnT can be synthesized via chemical, enzymatic, or cell factory approachs, among which the metabolic engineering-based cell factory synthesis is considered to be the most practical and effective. In this article, the occurrence and physiological effects of LNnT were reviewed in detail, the safety evaluation and regulation status of LNnT were described, various approaches to LNnT synthesis were comprehensively summarized and compared, and the future perspectives of LNnT-related studies were provided.

Occurrence, functional properties, and preparation of 3-fucosyllactose, one of the smallest human milk oligosaccharides

Human milk oligosaccharides (HMOs) are receiving wide interest and high attention due to their health benefits, especially for newborns. The HMOs-fortified products are expected to mimic human milk not only in the kinds of added oligosaccharides components but also the appropriate proportion between these components, and further provide the nutrition and physiological effects of human milk to newborns as closely as possible. In comparison to intensively studied 2'-fucosyllactose (2'-FL), 3-fucosyllactose (3-FL) has less attention in almost all respects. Nerveless, 3-FL naturally occurs in breast milk and increases roughly over the course of lactation with a nonnegligible content, and plays an irreplaceable role in human milk and delivers functional properties to newborns. According to the safety evaluation, 3-FL shows no acute oral toxicity, genetic toxicity, and subchronic toxicity. It has been approved as generally recognized as safe (GRAS). Biological production of 3-FL can be realized by enzymatic and cell factory approaches. The α1,3- or α1,3/4-fucosyltransferase is the key enzyme for 3-FL biosynthesis. Various metabolic engineering strategies have been applied to enhance 3-FL yield using cell factory approach. In conclusion, this review gives an overview of the recent scientific literatures regarding occurrence, bioactive properties, safety evaluation, and biotechnological preparation of 3-FL.

Bifidobacterium Species Colonization in Infancy: A Global Cross-Sectional Comparison by Population History of Breastfeeding

Bifidobacterium species are beneficial and dominant members of the breastfed infant gut microbiome; however, their health benefits are partially species-dependent. Here, we characterize the species and subspecies of Bifidobacterium in breastfed infants around the world to consider the potential impact of a historic dietary shift on the disappearance of B. longum subsp. infantis in some populations. Across populations, three distinct patterns of Bifidobacterium colonization emerged: (1) The dominance of Bifidobacterium longum subspecies infantis, (2) prevalent Bifidobacterium of multiple species, and (3) the frequent absence of any Bifidobacterium. These patterns appear related to a country’s history of breastfeeding, with infants in countries with historically high rates of long-duration breastfeeding more likely to be colonized by B. longum subspecies infantis compared with infants in countries with histories of shorter-duration breastfeeding. In addition, the timing of infant colonization with B. longum subsp. infantis is consistent with horizontal transmission of this subspecies, rather than the vertical transmission previously reported for other Bifidobacterium species. These findings highlight the need to consider historical and cultural influences on the prevalence of gut commensals and the need to understand epidemiological transmission patterns of Bifidobacterium and other major commensals.

Weighted analysis of 2'-fucosylactose, 3-fucosyllactose, lacto-N-tetraose, 3'-sialyllactose, and 6'-sialyllactose concentrations in human milk

Over 150 human milk oligosaccharides (HMOs) have been identified and their concentrations in human milk vary depending on Secretor and Lewis blood group status, environmental and geographical factors, lactation stage, gestational period, and maternal health. Quantitation of HMOs in human milk has been the focus of numerous studies, however, comprehensive and weighted statistical analyses of their levels in human milk are lacking. Therefore, weighted means, standard deviations, medians, interquartile ranges, and 90th percentiles for 2'-fucosyllactose (2'-FL), 3-fucosyllactose (3-FL), lacto-N-tetraose (LNT), 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) were calculated using random sampling and the levels of these HMOs in human milk reported in the literature. Probability distributions of the reported levels were also constructed. Although the levels reported in the published studies varied, the weighted means for 2'-FL, 3-FL, LNT, 3'-SL, and 6'-SL were calculated to be 2.58, 0.57, 0.94, 0.28, and 0.39 g/L, respectively, which are consistent with those that have been previously determined in other systematic analyses. Likely due to the use of weighting, the 90th percentiles were greater than the 95% confidence limits that have been previously calculated. Our study therefore provides accurate and important statistical data to help support the level of appropriate HMO supplementation in infant formula.

Synbiotics to prevent necrotising enterocolitis in very preterm or very low birth weight infants

BACKGROUND

Intestinal dysbiosis may contribute to the pathogenesis of necrotising enterocolitis (NEC) in very preterm or very low birth weight (VLBW) infants. Dietary supplementation with synbiotics (probiotic micro-organisms combined with prebiotic oligosaccharides) to modulate the intestinal microbiome has been proposed as a strategy to reduce the risk of NEC and associated mortality and morbidity.

OBJECTIVES

To assess the effect of enteral supplementation with synbiotics (versus placebo or no treatment, or versus probiotics or prebiotics alone) for preventing NEC and associated morbidity and mortality in very preterm or VLBW infants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, the Maternity and Infant Care database and CINAHL, from earliest records to 17 June 2021. We searched clinical trials databases and conference proceedings, and examined the reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing prophylactic synbiotics supplementation with placebo or no synbiotics in very preterm (< 32 weeks' gestation) or very low birth weight (< 1500 g) infants.

DATA COLLECTION AND ANALYSIS

Two review authors separately performed the screening and selection process,  evaluated risk of bias of the trials, extracted data, and synthesised effect estimates using risk ratio (RR), risk difference (RD), and mean difference, with associated 95% confidence intervals (CIs). We used the GRADE approach to assess the level of certainty for effects on NEC, all-cause mortality, late-onset invasive infection, and neurodevelopmental impairment.

MAIN RESULTS

We included six trials in which a total of 925 infants participated. Most trials were small (median sample size 200). Lack of clarity on methods used to conceal allocation and mask caregivers or investigators were potential sources of bias in four of the trials. The studied synbiotics preparations contained lactobacilli or bifidobacteria (or both) combined with fructo- or galacto-oligosaccharides (or both).  Meta-analyses suggested that synbiotics may reduce the risk of NEC (RR 0.18, 95% CI 0.09 to 0.40; RD 70 fewer per 1000, 95% CI 100 fewer to 40 fewer; number needed to treat for an additional beneficial outcome (NNTB) 14, 95% CI 10 to 25; six trials (907 infants); low certainty evidence); and all-cause mortality prior to hospital discharge (RR 0.53, 95% CI 0.33 to 0.85; RD 50 fewer per 1000, 95% CI 120 fewer to 100 fewer; NNTB 20, 95% CI 8 to 100; six trials (925 infants); low-certainty evidence). Synbiotics may have little or no effect on late-onset invasive infection, but the evidence is very uncertain (RR 0.84, 95% CI 0.58 to 1.21; RD 20 fewer per 1000, 95% CI 70 fewer to 30 more; five trials (707 infants); very low-certainty evidence). None of the trials assessed neurodevelopmental outcomes. In the absence of high levels of heterogeneity, we did not undertake any subgroup analysis (including the type of feeding).

AUTHORS' CONCLUSIONS

The available trial data provide only low-certainty evidence about the effects of synbiotics on the risk of NEC and associated morbidity and mortality for very preterm or very low birth weight infants. Our confidence in the effect estimates is limited; the true effects may be substantially different from these estimates. Large, high-quality trials would be needed to provide evidence of sufficient validity and applicability to inform policy and practice.

Exploring Human Milk Dynamics: Interindividual Variation in Milk Proteome, Peptidome, and Metabolome

Human milk is a dynamic biofluid, and its detailed composition receives increasing attention. While most studies focus on changes over time or differences between maternal characteristics, interindividual variation receives little attention. Nevertheless, a comprehensive insight into this can help interpret human milk studies and help human milk banks provide targeted milk for recipients. This study aimed to map interindividual variation in the human milk proteome, peptidome, and metabolome and to investigate possible explanations for this variation. A set of 286 milk samples was collected from 29 mothers in the third month postpartum. Samples were pooled per mother, and proteins, peptides, and metabolites were analyzed. A substantial coefficient of variation (>100%) was observed for 4.6% and 36.2% of the proteins and peptides, respectively. In addition, using weighted correlation network analysis (WGCNA), 5 protein and 11 peptide clusters were obtained, showing distinct characteristics. With this, several associations were found between the different data sets and with specific sample characteristics. This study provides insight into the dynamics of human milk protein, peptide, and metabolite composition. In addition, it will support future studies that evaluate the effect size of a parameter of interest by enabling a comparison with natural variability.

NMR Metabonomic Profile of Preterm Human Milk in the First Month of Lactation: From Extreme to Moderate Prematurity

Understanding the composition of human milk (HM) can provide important insights into the links between infant nutrition, health, and development. In the present work, we have longitudinally investigated the metabolome of milk from 36 women delivering preterm at different gestational ages (GA): extremely (<28 weeks GA), very (29–31 weeks GA) or moderate (32–34 weeks GA) premature. Milk samples were collected at three lactation stages: colostrum (3–6 days post-partum), transitional milk (7–15 days post-partum) and mature milk (16–26 days post-partum). Multivariate and univariate statistical data analyses were performed on the ¹H NMR metabolic profiles of specimens in relation to the degree of prematurity and lactation stage. We observed a high impact of both the mother’s phenotype and lactation time on HM metabolome composition. Furthermore, statistically significant differences, although weak, were observed in terms of GA when comparing extremely and moderately preterm milk. Overall, our study provides new insights into preterm HM metabolome composition that may help to optimize feeding of preterm newborns, and thus improve the postnatal growth and later health outcomes of these fragile patients.

A Comparison of Mother’s Milk and the Neonatal Urine Metabolome: A Unique Fingerprinting for Different Nutritional Phenotypes

The ability of metabolomics to provide a snapshot of an individual’s metabolic state makes it a very useful technique in neonatology for investigating the complex relationship between nutrition and the state of health of the newborn. Through an ¹H-NMR metabolomics analysis, we aimed to investigate the metabolic profile of newborns by analyzing both urine and milk samples in relation to the birth weight of neonates classified as AGA (adequate for the gestational age, n = 51), IUGR (intrauterine growth restriction, n = 14), and LGA (large for gestational age, n = 15). Samples were collected at 7 ± 2 days after delivery. Of these infants, 42 were exclusively breastfed, while 38 received mixed feeding with a variable amount of commercial infant formula (less than 40%) in addition to breast milk. We observed a urinary spectral pattern for oligosaccharides very close to that of the corresponding mother’s milk in the case of exclusively breastfed infants, thus mirroring the maternal phenotype. The absence of this good match between the infant urine and human milk spectra in the case of mixed-fed infants could be reasonably ascribed to the use of a variable amount of commercial infant formulas (under 40%) added to breast milk. Furthermore, our findings did not evidence any significant differences in the spectral profiles in terms of the neonatal customize centile, i.e., AGA (adequate for gestational age), LGA (large for gestational age), or IGUR (intrauterine growth restriction). It is reasonable to assume that maternal human milk oligosaccharide (HMO) production is not or is only minimally influenced by the fetal growth conditions for unknown reasons. This hypothesis may be supported by our metabolomics-based results, confirming once again the importance of this approach in the neonatal field.

A one-year study of human milk oligosaccharide profiles in the milk of healthy UK mothers and their relationship to maternal FUT2 genotype

Human milk oligosaccharides (HMOs) are indigestible carbohydrates with prebiotic, pathogen decoy and immunomodulatory activities that are theorized to substantially impact infant health. The objective of this study was to monitor HMO concentrations over 1 year to develop a long-term longitudinal dataset. HMO concentrations in the breast milk of healthy lactating mothers of the Cambridge Baby Growth and Breastfeeding Study (CBGS-BF) were measured at birth, 2 weeks, 6 weeks, 3 months, 6 months and 12 months postpartum. HMO quantification was conducted by high-performance anion-exchange chromatography with pulsed amperometric detection using a newly validated "dilute-and-shoot" method. This technique minimizes sample losses and expedites throughput, making it particularly suitable for the analysis of large sample sets. Varying patterns of individual HMO concentrations were observed with changes in lactation timepoint and maternal secretor status, with the most prominent temporal changes occurring during the first 3 months. These data provide valuable information for the development of human milk banks in view of targeted distribution of donor milk based on infant age. Maternal FUT2 genotype was determined based on identification at single-nucleotide polymorphism rs516246 and compared with the genotype expected based on phenotypic markers in the HMO profile. Surprisingly, two mothers genotyped as secretors produced milk that displayed very low levels of 2'-fucosylated moieties. This unexpected discrepancy between genotype and phenotype suggests that differential enzyme expression may cause substantial variation in HMO profiles between genotypically similar mothers, and current genotypic methods of secretor status determination may require validation with HMO markers from milk analysis.