Components of human breast milk: from macronutrient to microbiome and microRNA

Exposure to toxic metal(loid)s via breastmilk and stunting in infants living in the Lake Atitlán watershed, Guatemala

Guatemala has the highest child stunting prevalence in the Americas and is ranked sixth internationally. This paper examines concentrations of toxic metals and metalloids in the breastmilk of Mayan women in the Lake Atitlán watershed and explores potential relationships with stunting prevalence and demographic parameters to guide future research. We completed a cross-sectional study in 2022 (n = 80 mother/infant dyads) with 20 mother/infant dyads from each of four communities: San Juan La Laguna, San Pedro La Laguna, Panajachel, and Santiago Atitlán. We collected a breastmilk sample from each mother and measured the length of each infant (90-182 days old) to assess stunting (<-2 SD length-for-age below WHO growth standards median), and we collected community drinking water samples. The mean Z-score for stunting was -1.39 (SD = 1.24). Infants from Panajachel had a higher prevalence of stunting (X‾ = -2.06) than did infants from the other three communities. Metals and metalloids were quantified in breastmilk and water samples using inductively coupled plasma - mass spectrometry (ICP-MS). The concentrations of arsenic and lead in breastmilk were above the WHO safety standards in Panajachel and Santiago Atitlán, and concentrations of toxic metal(loid)s overall were highest in Panajachel. For infants from Panajachel and Santiago Atitlán, reduced Z-scores for stunting were associated with higher breastmilk concentrations of arsenic, barium, beryllium, and lead (p = 0.02-0.04). Water samples from these two communities exhibited greater concentrations of arsenic and barium than did water from other communities (p = 0.003-0.03). Significant associations between concentrations of arsenic, barium, beryllium, and lead with stunting score warrant a comprehensive assessment of the potential role of toxic metal(loid)s in child development. Stunting is a complex multifactorial problem; our results indicate that investigations of stunting should also evaluate exposures to toxic metal(loid)s in addition to the traditional causal factors such as malnutrition and chronic infections.

Human milk oligosaccharide secretion dynamics during breastfeeding and its antimicrobial role: A systematic review

BACKGROUND

Human milk oligosaccharides (HMOs) are bioactive components of breast milk with diverse health benefits, including shaping the gut microbiota, modulating the immune system, and protecting against infections. HMOs exhibit dynamic secretion patterns during lactation, influenced by maternal genetics and environmental factors. Their direct and indirect antimicrobial properties have garnered significant research interest. However, a comprehensive understanding of the secretion dynamics of HMOs and their correlation with antimicrobial efficacy remains underexplored.

AIM

To synthesize current evidence on the secretion dynamics of HMOs during lactation and evaluate their antimicrobial roles against bacterial, viral, and protozoal pathogens.

METHODS

A systematic search of PubMed, Scopus, Web of Science, and Cochrane Library focused on studies investigating natural and synthetic HMOs, their secretion dynamics, and antimicrobial properties. Studies involving human, animal, and in vitro models were included. Data on HMO composition, temporal secretion patterns, and mechanisms of antimicrobial action were extracted. Quality assessment was performed using validated tools appropriate for study design.

RESULTS

A total of 44 studies were included, encompassing human, animal, and in vitro research. HMOs exhibited dynamic secretion patterns, with 2′-fucosyllactose (2′-FL) and lacto-N-tetraose peaking in early lactation and declining over time, while 3-fucosyllactose (3-FL) increased during later stages. HMOs demonstrated significant antimicrobial properties through pathogen adhesion inhibition, biofilm disruption, and enzymatic activity impairment. Synthetic HMOs, including bioengineered 2′-FL and 3-FL, were structurally and functionally comparable to natural HMOs, effectively inhibiting pathogens such as Pseudomonas aeruginosa , Escherichia coli , and Campylobacter jejuni . Additionally, HMOs exhibited synergistic effects with antibiotics, enhancing their efficacy against resistant pathogens.

CONCLUSION

HMOs are vital in antimicrobial defense, supporting infant health by targeting various pathogens. Both natural and synthetic HMOs hold significant potential for therapeutic applications, particularly in infant nutrition and as adjuncts to antibiotics. Further research, including clinical trials, is essential to address gaps in knowledge, validate findings, and explore the broader applicability of HMOs in improving maternal and neonatal health.

Unlocking the potential of donkey Milk: Nutritional composition, bioactive properties and future prospects

Donkey milk has garnered increasing attention due to its remarkable similarity to human milk and its diverse bioactive properties. Analysis of its composition shows that donkey milk is characterized by high lactose content, low protein, low fat, a balanced calcium-to‑phosphorus ratio, and abundant in vitamins C and D, making it a promising human milk alternative. Additionally, donkey milk contains a unique composition of whey proteins and polyunsaturated fatty acids, contributing to its beneficial health effects such as antimicrobial, anti-inflammatory, antioxidant, and hypoallergenic properties. This review provides a comprehensive analysis of the nutritional profile of donkey milk in comparison to other mammalian milk sources. Furthermore, it highlights its bioactive potential and discusses the current challenges and future opportunities for expanding its applications in the dairy and health industries. Despite its valuable properties, the development of donkey milk products remains limited due to low milk yield and high production costs. Further research and technological advancements are necessary to optimize its utilization and commercial potential.

Factors and interventions that positively influence breastfeeding rates at six months postpartum: An integrative literature review

BACKGROUND

Despite the health benefits of breastmilk, many women discontinue breastfeeding prior to six months postpartum. Previous work from 2010 has identified women's breastfeeding intention, self-efficacy, and support as the main modifiable factors that influence breastfeeding at six months postpartum. However, due to societal changes during the past decade, factors influencing women's decision to continue breastfeeding requires further exploration.

AIM

To determine "what modifiable contemporary factors and interventions can positively influence women's decision to continue breastfeeding until six months postpartum?"

METHOD

An integrative literature review was conducted based on Whittemore and Knafl's framework. Databases were searched using combinations of the following main key words: breastfeeding, duration, factors, and interventions. Studies addressing the research question and published in English language since 2010 were included. Interventional studies were limited to only randomised controlled trials.

RESULTS

Women's positive breastfeeding intention, self-efficacy, and support remained the key modifiable factors that could increase breastfeeding rates up to six months postpartum. The main effective interventions included education support or counselling when they targeted women's needs, intention, self-efficacy and support; and were held over multiple sessions commencing antenatally or immediately after birth. Contemporary effective strategies included digital communications such as phone calls, virtual meetings and messaging via social media including FacebookTM, WhatsAppTM and TelegramTM. Main conceptual frameworks were motivational interviewing, planned behaviour theory and cognitive behavioural therapy.

CONCLUSION

Interventions that support breastfeeding up to six months should include contemporary strategies that target the main modifiable factors and are tailored based to women's needs and their sociocultural influences.

Comparison Between Antenatal and Postnatal Colostrum From Women With and Without Type 1 Diabetes

BackgroundSupplementary feeding, colostrum or, in some countries, commercial milk formula, is given to newborns of women with Type 1 diabetes to prevent neonatal hypoglycemia. Few studies have explored the content of colostrum from women with Type 1 diabetes.Research AimsThis study aimed to investigate the macronutrients in colostrum collected during pregnancy and in the early postpartum period to compare colostrum contents in women with and without Type 1 diabetes.MethodsIn this cohort study, we collected colostrum among 20 women, 10 with and 10 without Type 1 diabetes, at 10 different time points in gestational weeks 36-40 and postpartum Days 1-5. We measured carbohydrates, protein, fat, and kilocalories in colostrum using a human milk analyzer; and we analyzed data using linear mixed models. In a follow-up analysis, we compared the content of colostrum from Day 1 with the nutritional values provided on the commercial milk formula, using a one-sample t test.ResultsThere were no mean differences in carbohydrates (6.6 g/100 ml; 95% CI [6.3, 6.9] vs. 6.7 g/100 ml; 95% CI [6.4, 7.0] p = 0.29); kilocalories (71.1 kcal/100 ml; 95% CI [62.9, 79.3] vs. 85.3 kcal/100 ml; 95% CI [77.2, 93.3] p = 0.21], and fat (2.7 g/100 ml; 95% CI [1.8, 3.6] vs. 2.3 g/100 ml; 95% CI [1.4, 3.2] p = 0.55) in colostrum when comparing women with and without Type 1 diabetes. However, antenatal protein differed at all timepoints tested (p = 0.01). Colostrum macronutrients on Day 1 differed from that of commercial milk formula and all other colostrum time points, except Gestational Week 38.ConclusionsOur study provides insights into antenatal and postnatal colostrum macronutrients among women with and without Type 1 diabetes. Further studies are needed to understand the effects of supplementary feeding using antenatal or postnatal colostrum or commercial milk formula on neonatal hypoglycemia.

Total proteome and calcium-binding proteins from human breast milk: Exploring the impact of tobacco smoke exposure and environmental factors

This study integrates proteome analysis of human breast milk (HBM) from a homogeneous group of mothers who are of similar age and live in the same geographical area, along with an analysis of essential and potentially toxic elements in HBM in relation to lifestyle and environmental factors. This preliminary proteomic study, which examined 11 samples of HBM from lactating women, identified a total of 1619 proteins across all samples, revealing significant differences in proteomes influenced by lactation stages, parity, and exposure to tobacco smoke. The pilot study aimed to explore the feasibility of correlating certain proteins with several elements, considered as indicators of tobacco smoke and environmental influences on HBM. Notably, a clear and significant correlation was found between altered calcium content in HBM and the proteome fraction associated with calcium-binding proteins. The findings suggest that all analyzed factors impact the HBM proteome and the activity of certain enzymes.

European guidelines on diagnosis and treatment of phenylketonuria: First revision

Phenylketonuria (PKU) is an autosomal recessive inherited disorder of phenylalanine metabolism caused by deficiency of the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. Untreated, PKU results in elevated phenylalanine levels in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. For this first revision of the European PKU Guidelines previous recommendations were re-evaluated and updated according to new research findings. Twenty-one professionals were divided across four working groups and supported by a coordinator and chair. In addition to an update of the previous 70 recommendations, 20 new topics were included, resulting in a total of 87 statements in this first revision of the guidelines. Research publications were reviewed up until September 2022. Evidence was graded as high, moderate, low, very low or expert opinion and the recommendations were graded conditional or strong according to GRADE methodology. All recommendations were discussed during 14 plenary online or in person meetings. Recommendations were accepted if more than 75 % of the professionals were in agreement. When recommendations were not amended, the text reported in the European guidelines of 2017 remains valid.

Glycosyltransferases: glycoengineers in human milk oligosaccharide synthesis and manufacturing

Human milk oligosaccharides (HMOs) are a diverse group of complex carbohydrates that play crucial roles in infant health, promoting a beneficial gut microbiota, modulating immune responses, and protecting against pathogens. Central to the synthesis of HMOs are glycosyltransferases, a specialized class of enzymes that catalyse the transfer of sugar moieties to form the complex glycan structures characteristic of HMOs. This review provides an in-depth analysis of glycosyltransferases, beginning with their classification based on structural and functional characteristics. The catalytic activity of these enzymes is explored, highlighting the mechanisms by which they facilitate the precise addition of monosaccharides in HMO biosynthesis. Structural insights into glycosyltransferases are also discussed, shedding light on how their conformational features enable specific glycosidic bond formations. This review maps out the key biosynthetic pathways involved in HMO production, including the synthesis of lactose, and subsequent fucosylation and sialylation processes, all of which are intricately regulated by glycosyltransferases. Industrial methods for HMO synthesis, including chemical, enzymatic, and microbial approaches, are examined, emphasizing the role of glycosyltransferases in these processes. Finally, the review discusses future directions in glycosyltransferase research, particularly in enhancing the efficiency of HMO synthesis and developing advanced analytical techniques to better understand the structural complexity and biological functions of HMOs.

From Mother-Fetus Dyad to Mother-Milk-Infant Triad: Sex Differences in Macronutrient Composition of Breast Milk

Background: The composition of breast milk is influenced by a variety of factors, including maternal anthropometric characteristics, dietary and lifestyle habits, and lactation and feeding parameters. Emerging evidence also suggests that an infant's sex may play a role in shaping breast milk composition. Objective: This study aims to investigate the macronutrient composition of early breast milk up to 3 months postpartum, with a particular focus on potential differences related to the infant's sex. Methods: A total of 102 breast milk samples were collected at four time points across three lactation stages, representing colostrum, transitional, and mature milk, from a cohort consisting of 51 consenting mothers of Mediterranean origin who met the inclusion criteria. The samples were analyzed using mid-infrared spectroscopy to determine their macronutrient composition. Results: Colostrum from mothers of male infants contained approximately 60% higher levels of nitrogenous compounds, crude protein, true protein, and non-protein nitrogen compared to colostrum from mothers of female infants. Transitional milk for female infants contained higher fat, total solids, and energy. No significant differences in macronutrient composition were observed in mature milk between the sexes. For both sexes, colostrum contained more nitrogenous compounds and fewer total solids than mature milk. Male colostrum had lower carbohydrate levels compared to the later stages of lactation, while female samples showed no significant changes. Strong positive correlations between fat and crude protein were found for both sexes during the transitional and mature milk stages. In male colostrum, all macronutrients were interrelated. Conclusions: The observed differences in the composition of colostrum and transitional breast milk for male and female neonates suggest potential sex-specific nutritional adaptations during early lactation. These findings may have implications for personalized infant nutrition strategies in cases where breast feeding is hampered, as well as for understanding early neonatal adaptations.

Breastfeeding: The Multifaceted Impact on Child Development and Maternal Well-Being

Breastfeeding is recognized as the gold standard in infant nutrition, providing necessary nutrients for optimal growth and development. Beyond its nutritional function, breastfeeding has numerous benefits for both mother and child. This literature review examines the effects of breastfeeding on the development of the nervous and immune systems, its influence on cognitive development, and the impact of stress on lactation. In addition, it explores the emotional effects of breastfeeding on mothers, the challenges associated with exclusive breastfeeding, and the process of weaning along with its implications for both mother and infant. It is indicated that stress significantly affects lactation regulation, with elevated cortisol levels potentially disrupting hormonal balance. Furthermore, the essential roles of oxytocin, sialic acid, and docosahexaenoic acid in infant brain development and cognitive functions are highlighted. Breastfeeding is associated with the regulation of the baby's sleep through the effects of tryptophan, serotonin, and melatonin, which at the same time provide the baby with a sense of security with the mother. It is indicated that women who breastfeed are less likely to suffer from mental health problems and are at a lower risk of hypertension, diabetes, and cardiovascular disease. The weaning process is often a difficult time for mother and child; thus, it should be introduced gradually to minimize stress, anxiety, and potential mood disturbances in the mother.

The Effect of a Chronobiological Feeding Model on Growth Parameters and Length of Hospitalization in Preterm Infants: A Randomized Controlled Study

Background and Purpose: Preterm infants are born before the 37th gestational week and need prompt nutrition. The circadian rhythm is an internal 24-hour cycle regulated by endogenous molecules. Human milk contains different biological peptides at different times within this cycle. Chrononutrition is a feeding model that is adjusted to match the biological clock of the individual. This study tests chrononutrition as a superior feeding model in preterm infants. This study aimed to evaluate the effect of the chronobiological feeding model on growth parameters and discharge time among preterm infants. Methods: We conducted a prospective, randomized controlled trial in a tertiary neonatal intensive care unit between October 2021 and March 2022, randomized preterm infants to receive either chrononutrition (study group = 45) or standard feeding (control group = 46), and used the infant's follow-up form for data collection. Results: Among 91 neonates, the median gestational age was 33 weeks, and the mean birth weight was 2,100 g. Demographic findings and growth parameters showed no difference between the groups (p > 0.05). Weight gain and percentile measurements at discharge were statistically significantly higher in the study group (p = 0.002 and p = 0.003, respectively). Discharge time was statistically significantly lower after full enteral feeding and hospitalization time was shorter in the study group (p = 0.001). Conclusions: The chronobiological feeding model showcased significant positive effects on anthropometrics and percentile measurements at discharge and led to a 2-day reduction in the length of hospital stay.

Functional efficacy of Enterococcus faecium HN4 and Lactobacillus delbrueckii HN5 strains isolated from human milk

AIMS

The microbiota of human milk is described at length; however, variation in different bacterial genera in milk has been reported. Here, breast milk samples from Indian mothers were used to target bacterial species from the pool of microbial communities in human milk with probiotic potential.

MATERIALS AND METHODS

A culture-dependent technique was used to isolate bacterial cultures, and their physiological and functional properties were appraised.

RESULTS

Two bacterial cultures, E. faecium HN4 and L delbrueckii HN5, were identified as showing considerable tolerance to acid and bile conditions with 73.0-87.0% survival. The cultures showed other in vitro beneficial properties.

CONCLUSION

The study highlights the presence of potential probiotics in human milk that could be investigated for further use.

Maternal and Infant Predictors of Human Milk Macronutrient and Energy Concentrations in Rural Bangladesh: An Observational Cohort Study

BACKGROUND

Human milk macronutrient (protein, fat, and carbohydrate) and energy concentrations vary based on maternal and infant factors and time postpartum.

OBJECTIVES

This study aimed to determine the change in milk macronutrient and energy concentrations from approximately 2 to 5 months postpartum and identify factors associated with this variation among a lactation cohort in Bangladesh.

METHODS

In this prospective observational lactation cohort in rural Sylhet, Bangladesh, we collected hand-expressed mid-feed human milk samples and analyzed macronutrient concentrations using mid-infrared spectroscopy. We used the Wilcoxon rank-sum test to compare macronutrient and energy concentrations between time points and mixed linear regression to determine associations between predictors [maternal body mass index (BMI), maternal mid-upper arm circumference, infant gestational age, and infant small for gestational age status] and repeated measures of milk macronutrient and energy concentrations in models adjusted for parity, nicotine, and wealth index.

RESULTS

We enrolled 99 participants. From visit 1 (∼2 mo) to visit 2 (∼5 mo), median milk protein concentration decreased from 1.4 g/dL [interquartile range (IQR): 1.1-1.6 g/dL] to 0.8 g/dL (IQR: 0.6-1.1 g/dL), median fat concentration decreased from 4.6 g/dL (IQR: 3.8-5.5 g/dL) to 2.8 g/dL (IQR: 2.1-3.7 g/dL), and median energy concentration decreased from 22.7 kcal/oz (IQR: 20.6-25.1 kcal/oz) to 17.5 kcal/oz (IQR: 15.6-19.9 kcal/oz). Maternal overweight status was associated with a lower carbohydrate concentration (2 mo-mean difference: -0.16 g/dL; 95% CI: -0.28, -0.03 g/dL; 5 mo-mean difference: -0.14 g/dL; 95% CI: -0.26, -0.02; reference = normal BMI).

CONCLUSIONS

The decline of protein, fat, and energy concentrations over time is a potential concern for Bangladesh's vulnerable population of human milk-fed infants, as these nutrients have implications for infant growth and neurodevelopment.

Dairy Foods: A Matrix for Human Health and Precision Nutrition-Effect of processing infant milk formula on protein digestion and gut barrier health (in vitro and preclinical)

The infant gut is immature and permeable with high gastric pH, low protease activities, and underdeveloped intestinal architecture. Protein digestion in the upper gastrointestinal tract of infants is slow and incomplete. During manufacture, infant milk formula (IMF) is typically heat-treated so it is safe for human consumption. This heat treatment causes denaturation and aggregation of milk proteins, and formation of undesirable Maillard reaction products. The aim of this review is to critically summarize the in vitro and preclinical data available on the effect of IMF thermal processing on protein digestion and gut barrier physiology in the immature infant gut. Recent research efforts have focused on reducing thermal loads during IMF manufacturing by sourcing ingredients with low thermal loads, by reducing temperatures during IMF processing itself, and by seeking alternative processing technologies. This review also aims to evaluate whether these thermal reductions have a knock-on effect on protein digestion and gut barrier health in the infant. The ultimate aim is to create a safe next-generation IMF product that more closely mimics human breast milk in its protein digestion kinetics and its ability to promote gut barrier maturity in the infant.

Transporters and drug secretion into human breast milk

INTRODUCTION

Medication use is highly prevalent in breastfeeding persons, posing potential risks for drug exposure to nursing infants. Transporters in the lactating mammary gland carry pharmacological and toxicological significance, as they can mediate the active transfer of drugs and nutrients into breastmilk.

AREAS COVERED

In this narrative review, we searched and compiled current knowledge on the transport of drugs in the human mammary gland from literature indexed in PubMed (current as of 25 October 2024), and clinical evidence demonstrating active transport of drugs into milk is provided. In vitro and in vivo models of the mammary gland are outlined in brief and known drug transporters at the blood-milk barrier and their potential relevance to drug concentrations in milk are described in detail.

EXPERT OPINION

Although clinical data show that membrane transporters mediate the transfer of multiple drugs into breast milk, our ability to predict milk concentrations for these drugs is limited. Improving our understanding of the transporter biology and pharmacology in the mammary gland is crucial for developing models to predict drug concentrations in human milk, which will support clinicians and lactating individuals in making rational decisions to balance the benefits of breastfeeding and the risks of drug exposure to infants.

Chemical Components in the Breast Milk of Passive Smoker Women: A Systematic Review and Health Risks Assessment

Breast milk from passive smokers may contain various harmful chemical components, primarily due to exposure to tobacco smoke. This systematic review was conducted on the chemical components of breast milk in women who were exposed to environmental tobacco smoke (ETS). English language-published papers were advanced searched without time limitation until April, 2024 in Web of Science, PubMed, and Scopus databases. A total of 1156 papers were recorded in the initial search of these databases. Finally, 18 articles met the inclusion criteria and were included. Our results showed that metals (n = 10) and heterocyclic compounds (n = 9) (cotinine, nicotine, and nornicotine) were the most commonly reported compounds in the included studies. Cotinine was the most frequently reported compound in mature milk (n = 9) and colostrum (n = 3). Among metals in mature milk, cadmium (n = 8) and lead (n = 6) are the most common compounds. Metals in colostrum were just reported in one study. The cancer risk (CR) values showed a decreasing pattern in the order of Sr > Mn > U > Co > Pb > Cr > As > Cd > Be for both aged infant groups. Parents should be encouraged to not smoke, as well as must be advised of the potential risks of ETS exposure to their babies. It is recommended that routine and continuous monitoring of probable sources of chemical contamination of breast milk due to environmental exposures should be done to discover the influencing factors and develop suitable interventions for decreasing the exposure/contamination.

Mapping the current knowledge on leucocytes in human breastmilk: a scoping review protocol

INTRODUCTION

The immunological composition of breastmilk has gained research interest as breastfeeding has been persistently correlated with improved health outcomes in children. Immune cells, also known as leucocytes, are key components of the body's immune system, but they remain understudied in breastmilk. The relevance of breastmilk leucocytes for breastfeeding-mediated immune benefits remains controversial. To identify the current state-of-the-art on breastmilk leucocyte research, unearth knowledge gaps and propose research priorities, a scoping review is necessary.

METHODS AND ANALYSIS

This scoping review will address the general question of what is known about leucocytes in human breastmilk. The development of this scoping review protocol adhered to the recommendations set forth by the Joanna Briggs Institute guidelines. Peer-reviewed research articles published in English, French or Spanish will be eligible for inclusion in the scoping review. The initial literature search was conducted in January 2024 within the Medline, Embase, Cochrane Central and BVS databases.

ETHICS AND DISSEMINATION

This review does not require ethics approval. Our dissemination strategy includes peer-review publication and presentations at conferences and to relevant stakeholders.

REGISTRATION DETAILS

This protocol was registered in Open Science Framework (available at: https://osf.io/kwfsy) on 19 February 2024.

Growth and gastrointestinal tolerance of healthy formula-fed infants: a multicentre, prospective observational study

BACKGROUND

Infant formula with human milk oligosaccharides (HMOs) and increased β-palmitate mimics breast milk nutritional composition and clinical benefits. We aimed to assess formula-fed infant growth, gastrointestinal tolerance, infections, and parental satisfaction with a partly fermented infant formula with an improved lipid profile (enriched with β-palmitate and docosahexaenoic/arachidonic acid) and short and long-chain oligosaccharides (scGOS/lcFOS [9:1]) and HMOs.

METHODS

A prospective descriptive observational study in healthy infants with formula feeding or breastfeeding (reference population) was conducted in six Spanish primary care centres following routine clinical practice. In the first, second and fourth month of life visits sociodemographic, clinical, and anthropometric variables (weight, length, head circumference), stool consistency (Brussels Infant and Toddler Stool Scale [BITSS]), gastrointestinal symptoms, infections incidence and associated healthcare resource utilisation, and caregivers' satisfaction with formula were collected. A descriptive statistical analysis was performed (STATA-v.14). Growth was estimated as the mean (standard deviation) increase in the anthropometric variables and z-scores.

RESULTS

A total of 61 formula-fed and 65 breastfed infants were included in the study (50.8% male). The average increase in weight, length and head circumference in the formula feeding and in the breastfeeding groups from the first to the fourth month of life was 2,566 (496) g, 9.7 (1.7) cm and 4.4 (1.0) cm, and 2,571 (702) g, 9.8 (1.8) cm and 4.4 (1.1) cm, respectively. The weight z-score was -0.1 (0.7) for formula-fed and 0.1 (1.1) for breastfed infants. In all visits, more than 88% of infants had loose/watery stools and most infants suffered gastrointestinal symptoms with low/medium frequency. In the fourth month of life visit, 16 (26.2%) formula-fed and 16 (24.6%) breastfed infants had infections, mainly respiratory, with 16% of formula-fed and 12% of breastfed infants requiring treatment. Most formula-feeding caregivers had a good/very good opinion of formula (85.2%). 75.4% infants drank the whole feeding bottle.

CONCLUSIONS

The growth, gastrointestinal tolerance, and incidence of infections of healthy formula-fed infants during the first four months of life were appropriate and in line with WHO standards. Formula feeding caregivers were satisfied with this partly fermented infant formula with an improved lipid profile and oligosaccharides.

Effect of Different Ratios of α-Lactalbumin to β-Casein in Infant Formula on True Ileal Digestibility and Intestinal Morphology of Suckling Piglets

Breast milk (BM) is the optimal nutrition source for infants, providing highly digestible proteins. In contrast, the digestibility of proteins in infant formula (IF) varies, influenced by differences in proteins such as α-lactalbumin (α-La) and β-casein (β-CN). This study aimed to evaluate the true ileal digestibility (TID) of amino acids (AAs) in BM and IF with varying α-La and β-CN contents using neonatal piglets. Twenty-four 11-day-old piglets (4 groups; 6 replicates/group) received either a nitrogen-free diet, IF (high infant formula (HIF) with 1.74 g/100 α-La and 2.3 g/100 β-CN; low infant formula (LIF) with 1.07 g/100 α-La and 1.85 g/100 β-CN), or BM (1.82 g/100 α-La and 3.05 g/100 β-CN) for 7 days after 3 prefeed days. IF had higher concentrations of nitrogen, serine, threonine, and proline than BM. Glutamic acid was the most abundant AA in IF and BM, while methionine in BM and LIF or tryptophan in HIF was the least. BM showed the highest TID of AAs, with the LIF had the lowest. The HIF group's TID for AAs, especially tryptophan, was similar to BM and significantly better than LIF. These results suggest that adjusting the α-La and β-CN ratio in IF can improve AA digestibility, approaching BM levels.

Breastfeeding and Future Cardiovascular, Kidney, and Metabolic Health-A Narrative Review

The benefits of breastfeeding for both mother and infant are generally recognized; however, the connections between breast milk, lactation, and long-term offspring health and disease remain incompletely understood. Cardiovascular-kidney-metabolic syndrome (CKMS) has become a major global public health challenge. Insufficient breast milk supply, combined with various early-life environmental factors, markedly increases the future risk of CKMS, as highlighted by the developmental origins of health and disease (DOHaD) concept. Given its richness in nutrients and bioactive components essential for infant health, this review focuses on reprogramming strategies involving breast milk to improve offspring's cardiovascular, kidney, and metabolic health. It also highlights recent experimental advances in understanding the mechanisms driving CKMS programming. Cumulatively, the evidence suggests that lactational impairment heightens the risk of CKMS development. In contrast, early interventions during the lactation period focused on animal models that leverage breast milk components in response to early-life cues show potential in improving cardiovascular, kidney, and metabolic outcomes-an area warranting further investigation and clinical translation.

The Legacy of COVID-19 in Breast Milk: The Association of Elevated Anti-Inflammatory and Antimicrobial Proteins with Vaccination or Infection

BACKGROUND

Breast milk is a rich source of antimicrobial and anti-inflammatory compounds, owing to its diverse array of bioactive molecules. This study explores the presence and activity of natural antimicrobial agents in breast milk, particularly in the context of the SARS-CoV-2 pandemic.

MATERIALS AND METHODS

Breast milk samples were collected from 50 breastfeeding mothers, including those who had either been vaccinated against SARS-CoV-2 or had recovered from the infection. These samples were compared with a control group consisting of 10 unvaccinated mothers with no history of COVID-19. Key antimicrobial and immune-regulatory proteins-lactoferrin, lactadherin, furin, tenascin C, granzyme B, and chitinase 3-like 1-were quantified using the Luminex multiplex analyzer.

RESULTS AND DISCUSSION

All targeted biomarkers were detected in breast milk, providing insights into the immune profile transferred to infants following COVID-19 infection or vaccination. These bioactive molecules highlight breastfeeding's role in providing passive immunity and antimicrobial protection. The protein levels were found to be influenced by factors such as maternal inflammation, infant age, delivery mode, and parity, emphasizing the dynamic interaction between maternal immunity, lactation biology, and infant development.

CONCLUSION

Breastfeeding serves as a powerful anti-SARS-CoV-2 defense mechanism, supported by the activity of lactoferrin, lactadherin, and furin, reinforcing its critical role in child health.

Human Milk Feeding in Inherited Metabolic Disorders: A Systematic Review of Growth, Metabolic Control, and Neurodevelopment Outcomes

Human milk (HM) is the optimal source of nutrition for infants. Yet the suitability of HM macronutrient composition, paired with the challenge of regulating HM intake, may deserve some consideration for infants with inherited metabolic disorders (IMDs) requiring restrictive and controlled dietary management. Except for classic galactosemia, HM feeding is expected to be feasible, allowing infants to maintain metabolic stability, while growing and developing optimally. However, information about HM feeding in nonphenylketonuria (PKU) literature is scarce. In this systematic review, 52 studies were included, representing 861 infants (86% PKU) receiving HM after IMD diagnosis (mean duration 4-10 months depending on the IMD). For non-PKU IMDs (e.g., other amino acidopathies, urea cycle disorders, organic acidemias, fatty acid oxidation disorders), outcomes of HM feeding were available for few infants, except for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency (n = 48). In PKU, HM feeding combined with phenylalanine-free formula, led to adequate metabolic control (25 studies), growth (15 studies), and neurodevelopment (10 studies). For other IMDs, more evidence is required, but the limited data suggest that HM feeding is possible, with attentive monitoring and disease-specific formula supplementation where applicable. In MCAD deficiency, ensuring adequate HM intake is essential, as symptoms were more frequently reported in exclusively breastfed infants. No IMD-specific articles were found on the relationship between HM feeding and many other outcomes of interest (e.g., immune status or comorbidity risk later in life). With the exception of galactosemia, HM feeding is expected to benefit infants with IMD. More data should be published for IMDs other than PKU.

Comparison Between SGLT2 Inhibitors and Lactation: Implications for Cardiometabolic Health in Parous Women

Sodium-glucose cotransporter-2 (SGLT2) inhibition and lactation result in the excretion of large amounts of glucose in urine or milk and are associated with a lower risk of cardiovascular events. The respective mechanisms behind this association with cardiovascular protection are not clear. This review compares the contribution of noninsulin-mediated glucose transport during pharmacologic inhibition of SGLT2 with noninsulin-mediated glucose transport during lactation in terms of the implications for the cardiometabolic health of parous women. The search topics used to obtain information on SGLT2 inhibitors included mechanisms of action, atherosclerosis, and heart failure. The search topics used to obtain information on lactation included cardiovascular health and milk composition. Subsequent reference searches of retrieved articles were also used. Active treatment with SGLT2 inhibitors affects glucose and sodium transport in the kidneys and predominantly protects against hospitalization for heart failure soon after the onset of therapy. Active lactation stimulates glucose transport into the mammary gland and improves subclinical and clinical atherosclerotic vascular disease years after delivery. Both SGLT2 inhibitors and lactation have effects on a variety of glucose transporters. Several mechanisms have been proposed to explain the cardiometabolic benefits of SGLT2 inhibition and lactation. Learning from the similarities and differences between both processes will advance our understanding of cardiometabolic health for all people.

Challenges and Opportunities in Quantifying Bioactive Compounds in Human Breastmilk

Breastmilk is a complex biological fluid containing over a thousand bioactive proteins, lipids, cells and small molecules that provide nutrition and immunological protection for infants and children. The composition of breastmilk is unique to each individual and can also vary within individuals according to breastfeeding duration, maternal health, time of day, and other factors. As such, the composition of breastmilk can be considered a "fingerprint" that could be interrogated to identify biomarkers of breast health and disease. However, accurate quantification of bioactive components in breastmilk remains a significant challenge. Approaches such as immunoassays and mass spectrometry have been largely applied to study blood or other biological fluids and require validation and optimisation before these techniques can be used to accurately quantify bioactive compounds in breastmilk. Development of protocols specific to breastmilk should be carried out with high precision, confidence, and sensitivity. This review explores the challenges and opportunities associated with different techniques for quantification of breastmilk bioactive components.

Regional and longitudinal dynamics of human milk protein components assessed by proteome analysis on a fast and robust micro-flow LC-MS/MS system

An in-depth exploration of molecular composition of human milk could provide a scientific basis for the development of substitutes. The present study was conducted to analyze human milk proteins from 110 individuals from five regions of China and across three stages of lactation to investigate the change patterns. We developed a micro-flow liquid chromatography tandem mass spectrometry (μLC-MS/MS) system with data-independent acquisition (DIA) proteomics technology that can rapidly and stably characterize the human milk proteome. In total, 2796 proteins were identified. Among these proteins, CPM, ACSL1, and RPL13 changed significantly during lactation, and SCP2, GALK1 and GALE changed significantly between regions. Bioinformatics analysis revealed that human milk is altered by complex interactions between genetic and environmental factors. Our results not only reveal the regional and longitudinal patterns of change in human milk proteome but also provide theoretical basis and technical support for the production and quality control of infant formula.

Maternal obesity, age and infant sex influence the profiles of amino acids, energetic metabolites, sugars, and fatty acids in human milk

PURPOSE

This study aimed to evaluate whether maternal nutritional status, maternal age, mode of delivery, and the infant's sex influence the profiles of amino acids, energetic metabolites, sugars, and fatty acids and as well as the metabolic pathways in mature human milk human milk (HM).

METHODS

This was a cross-sectional, prospective, and observational study. HM samples from normal weight (NW, n = 60), overweight (OW, n = 35), and obese (OB, n = 14) women were analyzed using a non-targeted GC-MS method to identify the metabolome. Data obtained were analyzed with Metaboanalyst software (v. 5.0) and SPSS (v.25.0).

RESULTS

OB women HM contains a higher proportion of amino acids such as leucine, lysine, tyrosine, and aspartic acid, energy metabolites such as lactic and succinic acid, and sugars and derivatives such as fucose, rhamnose, and gluconic acid (p < 0.05) compared with normal weight women HM. HM from women > 25 years of age contains a lower proportion of lauric acid and a higher proportion of leucine and tyrosine (p < 0.05) than ≤ 25 years women HM. Also, HM intended for female infants has a higher leucine and gluconic acid content. The main altered metabolic pathways in OB women HM correspond to amino acids and energetic metabolism.

CONCLUSION

OB women HM provides more amino acids, energetic molecules, and sugars. Increased maternal weight, BMI, and body fat mass predispose to more leucine and aspartic acid in HM. Maternal age influences lauric acid, leucin, and tyrosine levels, while the infant's sex influences leucine and gluconic acid levels in HM. The impact of obese women's HM metabolome on the offspring's physiology needs to be explored.

TRIAL REGISTRATION

R-2021-785-096.

Bidirectional Interplay Among Non-Coding RNAs, the Microbiome, and the Host During Development and Diseases

It is widely known that the dysregulation of non-coding RNAs (ncRNAs) and dysbiosis of the gut microbiome play significant roles in host development and the progression of various diseases. Emerging evidence has highlighted the bidirectional interplay between ncRNAs and the gut microbiome. This article aims to review the current understanding of the molecular mechanisms underlying the crosstalk between ncRNAs, especially microRNA (miRNA), and the gut microbiome in the context of development and diseases, such as colorectal cancer, inflammatory bowel diseases, neurological disorders, obesity, and cardiovascular disease. Ultimately, this review seeks to provide a foundation for exploring the potential roles of ncRNAs and gut microbiome interactions as biomarkers and therapeutic targets for clinical diagnosis and treatment, such as ncRNA mimics, antisense oligonucleotides, and small-molecule compounds, as well as probiotics, prebiotics, and diets.

Donor Human Milk Fat Content Is Associated with Maternal Body Mass Index

Introduction: Donor human milk is increasingly being utilized for both preterm and term infants when mother's milk is unavailable. With the rising prevalence of maternal overweight and obesity, it is crucial to evaluate the relationship between maternal body mass index and the fat and energy content of donor human milk. Objectives: To assess the impact of maternal body mass index on human milk fat content. Methods: A cross-sectional study was carried out using retrospective data from women who made their first human milk donation at ≥15 days postpartum at a human milk bank in São Paulo, Brazil, from January 2018 to December 2020. Data of sociodemographic, obstetric, health, and anthropometric measures were collected by the human milk bank staff. Milk fat and energy content were determined using the crematocrit test. Analysis of variance and multiple linear regression were used to compare means of crematocrit and fat. We determined the p-values using a test of heterogeneity and linear trend and presented the one with the lower p-value. Results: Most donors were between 25 and 35 years old, had higher education, were employed, and lived with a partner. At the time of milk donation, 40.9% of women were overweight or obese. The fat (1.09 g/dL) and energy (9.83 kcal/dL) content of human milk were higher in obese donor compared with eutrophic donors. Conclusions: The fat and energy content of human milk were associated with maternal body mass index, suggesting the potential value for selective use of high fat and high calorie donor milk for very low birthweight or premature infants.

Nutrient composition of human milk of Indian mothers: relation with maternal and infant anthropometry

The aim of the study was to determine the nutrient composition of human milk (HM) of Indian mothers and investigate its association with maternal and infant anthropometric measures. Human milk is an ideal source of nutrition for optimum growth and development of infant. Among Indian mothers, HM composition data is scanty, especially during prolonged lactation. Mother-infant dyads (n = 50) comprising of two lactation group (0-6 m, n = 26) and (7-12 m, n = 24) residing in Delhi, India were enrolled. Height, weight, BMI, MUAC and head circumference were measured and compared with reference standard. The macronutrients and micronutrients of HM were analysed using MIRIS analyzer, ICP-AES and HPLC. Correlation plots were generated between HM nutrients and maternal, infant anthropometry. Mean BMI of mothers were 19.6 ± 2.6 (0-6 m) and 21.2 ± 3.7 (7-12 m) kg/m2. Around 26% of mothers were underweight, 28% overweight. Among infants, 26% were underweight, wasted (18%), stunted (34%) and overweight (10%). The macronutrient composition of human milk were similar to reference values (means ± standard deviation). Both lactation group showed similar HM nutrient composition. Significant positive associations (r = 0.3-0.5) were found between maternal height, infant HCZ with HM energy, fat; maternal prepregnancy-weight, MUAC with retinol; maternal MUAC with crude protein.

Differences in immune cells and gene expression in human milk by parity on integrated scRNA sequencing

BACKGROUND

Human breast milk (HBM) is an important source of tolerogenic immune mediators that influence the infant immune system. HBM-derived immune components are affected by various factors; however, few studies have examined the relationship between parity and immune cell profiles of HBM.

PURPOSE

This study aimed to clarify the effects of parity on HBM immune cell heterogeneity and gene expression by integrating and analyzing publicly available single-cell RNAsequencing (scRNA-seq) datasets.

METHODS

We clarified the effects of parity on HBM immune cell heterogeneity and gene expression by integrating and analyzing publicly available scRNA-seq datasets.

RESULTS

The proportion of innate immune cells was significantly higher in the primiparous versus multiparous group, whereas the proportion of adaptive immune cells was significantly higher in the multiparous group (P=0.021). The 2 immune clusters were reannotated and classified into monocyte, T/B cell, and CD45¯ groups. The proportions of monocytes and T/B cells were higher in the primiparous and multiparous groups, respectively. In a gene set enrichment analysis of monocytes, genes with a direct role in the infant immune system and immune response-related genes were more highly expressed in the primiparous group.

CONCLUSION

Our results support the parity-dependent differences in gene expression between innate and adaptive immune cells.

Flavonoids in breast milk and their absorption, metabolism, and bioactivity in infants

Flavonoids are present in plant foods such as vegetables and fruits and exhibit various physiological effects, including antioxidant and anti-inflammatory properties. Ingested flavonoids are absorbed from the intestinal tract and circulated in the blood. Some studies have indicated the presence of flavonoids in breast milk. However, information on their metabolites and concentrations in breast milk and the subsequent transfer to and physiological functions in infants is limited. Therefore, this review presents a compilation of recent findings on the transfer of flavonoids to infants via breast milk and their bioactivities.

The Impact of Maternal Chronic Inflammatory Conditions on Breast Milk Composition: Possible Influence on Offspring Metabolic Programming

Breastfeeding is the best way to provide newborns with crucial nutrients and produce a unique bond between mother and child. Breast milk is rich in nutritious and non-nutritive bioactive components, such as immune cells, cytokines, chemokines, immunoglobulins, hormones, fatty acids, and other constituents. Maternal effects during gestation and lactation can alter these components, influencing offspring outcomes. Chronic inflammatory maternal conditions, such as obesity, diabetes, and hypertension, impact breast milk composition. Breast milk from obese mothers exhibits changes in fat content, cytokine levels, and hormonal concentrations, potentially affecting infant growth and health. Similarly, diabetes alters the composition of breast milk, impacting immune factors and metabolic markers. Other pro-inflammatory conditions, such as dyslipidemia and metabolic syndrome, have been barely studied. Thus, maternal obesity, diabetes, and altered tension parameters have been described as modifying the composition of breast milk in its macronutrients and other important biomolecules, likely affecting the offspring's weight. This review emphasizes the impact of chronic inflammatory conditions on breast milk composition and its potential implications for offspring development through the revision of full-access original articles.

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.

A Pilot Study Exploring the Relationship Between Milk Composition and Microbial Capacity in Breastfed Infants

BACKGROUND

Maternal obesity may contribute to childhood obesity in a myriad of ways, including through alterations of the infant gut microbiome. For example, maternal obesity may contribute both directly by introducing a dysbiotic microbiome to the infant and indirectly through the altered composition of human milk that fuels the infant gut microbiome. In particular, indigestible human milk oligosaccharides (HMOs) are known to shape the composition of the infant gut microbiome. The goal of this study was to characterize the HMO profiles of normal-weight and overweight mothers and to quantitatively link HMO concentrations to the taxonomic composition and functional potential of the infant gut microbiome.

METHODS

Normal-weight (BMI = 18.5-24.9; n = 9) and overweight/obese (OW/OB; BMI > 25; n = 11) breastfeeding mothers and their infants were enrolled in this single-center, cross-sectional pilot study. Human milk from the mothers and rectal stool swabs from the infants were collected 7-9 weeks postpartum. The HMO composition, microbiome composition, and microbial functions were assessed using HPLC, 16S rRNA gene sequencing, and metagenomic sequencing, respectively.

RESULTS

Neither the HMO profiles nor the infant microbiome composition varied according to maternal BMI status. Taxonomically, the gut microbiota of infants were dominated by typical gut lineages including Bifidobacterium. Significant correlations between individual HMOs and bacterial genera were identified, including for Prevotella, a genus of the Bacteroidota phylum that was positively correlated with the concentrations of lacto-N-neotetraose (LNnT) and lacto-N-hexaose (LNH). Using metagenomic assembled genomes, we were also able to identify the broad HMO-degradative capacity across the Bifidobacterium and Prevotella genera.

CONCLUSIONS

These results suggest that the maternal BMI status does not impact the HMO profiles of human milk. However, select HMOs were correlated with specific bacterial taxa, suggesting that the milk composition influences both the taxonomic composition and the functional capacity of the infant gut microbiome.

[Clinical practice guidelines for the diagnosis and treatment of anemia of prematurity (2025)]

Anemia of prematurity (AOP) is a multifactorial condition associated with congenital iron deficiency, low erythropoietin levels, a short lifespan of red blood cells, and iatrogenic blood loss. AOP is a common complication in premature infants that can adversely affect growth, development, and long-term neurocognitive outcomes. To standardize the diagnosis and treatment of AOP, the Neonatal Clinical Practice Guidelines Expert Committee and the Neonatal Evidence-Based Medicine Group of the Commission of Neonatal Medicine of the Cross-Strait Medical and Health Exchange Association, along with the Editorial Office of the Chinese Journal of Contemporary Pediatrics, have developed the "Clinical practice guidelines for the diagnosis and treatment of anemia of prematurity (2025)", based on the World Health Organization's handbook for guideline development and the formulation/revision principles of Chinese clinical practice guidelines. This guideline addresses eight clinical issues related to AOP, including risk factors, early identification, etiological diagnosis, diagnostic criteria, early prevention, transfusion therapy, strategies to improve prognosis, and post-discharge follow-up. It presents 29 recommendations formed from current evidence and expert consensus, aiming to provide guidance and decision-making support for healthcare professionals in the diagnosis and treatment of AOP.

The validation of an LC-MS/MS method for the quantification of vitamin D metabolites in human milk and their biological variability in Gambian women

Vitamin D is required for healthy growth and development, but data on human milk vitamin D content is limited. We describe a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the analysis of vitamin D metabolites in human milk, and its application in samples collected on two consecutive days from women in rural Gambia. Vitamin D compounds were extracted from 1 mL of milk by liquid-liquid extraction and derivatised with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) prior to analysis by LC-MS/MS. The limit of quantification was 0.05 nmol/L for vitamin D2, 0.025 nmol/L for vitamin D3 and 0.1 nmol/L for 25(OH)D2 and 25(OH)D3. Within- and between-day imprecision was <12 % for all analytes except vitamin D2 (14 %). From all data combined, geometric mean (-/+ 1 SD) vitamin D3 concentration was 0.94 (0.43, 1.80) nmol/L and for 25(OH)D3 0.32 (0.23, 0.42) nmol/L. The within-person (intra-individual) coefficient of variation (%CV) was 32 % and 12 % for vitamin D3 and 25(OH)D3, respectively. Between-person (inter-individual) %CVs were 89 % and 34 % for vitamin D3 and 25(OH)D3, respectively. There was no significant association between vitamin D metabolite concentrations and milk fat (creamatocrit). Mean vitamin D content of human milk as ARA averaged 42 IU/L with 25(OH)D3 responsible for around two-thirds of the biological activity. In conclusion, this work describes a reliable LC-MS/MS method for quantification of vitamin D and 25(OH)D in low volumes of human milk providing a platform for future work. This study contributes to current understanding of variability of milk vitamin D content.

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.

Dietary intake and growth of HIV exposed and unexposed 6-12 months old infants in South Africa

Factors affecting the growth of HIV-exposed-uninfected (HEU) children are multi-factorial, with limited information available on the dietary intake from 6 months. This study compared the dietary intake, micronutrient composition of breastmilk, and growth of HEU and HIV-unexposed-uninfected (HUU) infants aged 6 and 12 months in an urban setting. A repeated cross-sectional study used structured questionnaires to collect socio-demographic, dietary intake, food group data, and anthropometric measurements in the Siyakhula study. The HEU (48%) and HUU (52%) infants were included (total n = 181). At 6 months, HEU infants had lower weight-for-age z-scores (WAZ) (-0.6 ± 1.1 vs. 0.1 ± 1.2; p < 0.001), length-for-age z-scores (-0.8 ± 1.4 vs. -0.1 ± 1.2; p < 0.001), and mid-upper-arm circumference-for-age z-scores (MUACAZ) (0.5 ± 1.1 vs. 1.0 ± 0.9; p < 0.001) than HUU infants. At 12 months, HEU infants had lower WAZ, MUACAZ, and weight-for-length z-scores compared to HUU infants (p < 0.05). Stunting was found at 6 (15%) and 12 (12%) months in HEU infants. The micronutrient composition of breastmilk fed to both groups was similar. Breastfeeding rates were lower in HEU than in HUU infants at 6 (49% vs. 64%; p = 0.005) and 12 (24% vs. 46%; p = 0.002) months. Less than 3% of HEU and HUU infants achieved minimal dietary diversity scores at 12 months. Dietary intake of fat was similar in all breastfed infants, but iron and vitamin B12 were higher in non-breastfed HEU infants at 12 months. HEU infants had lower breastfeeding rates than HUU infants. A lack of dietary diversity was found in all infants. Nutrition education and counselling in the complementary feeding phase are essential for optimal growth.

Effects and mechanism of puerarin on lactation of postpartum hypogalactia mice

Objectives

Insufficient breast milk supply is a common reason cited for discontinuing breastfeeding prematurely. Natural galactagogues offer promise as a solution for mothers with low milk production. This study aimed to explore puerarin's potential effects and underlying mechanism on lactation of postpartum hypogalactia mice.

Materials and Methods

Postpartum mice were randomly assigned to five groups: control group, agalactosis model group, domperidone group (3.5 mg/kg), low dose puerarin group (18 mg/kg), and high dose puerarin group (72 mg/kg). The effects of puerarin on postpartum hypogalactia mice were evaluated by lactation indicators and pathological morphology. Related hormones and prolactin receptor (PRLR)/Janus kinase 2 (JAK2)/signal transduction and activator (STAT) 5 signaling pathway were also measured.

Results

Puerarin significantly improved lactation yield and stimulated mammary gland development in postpartum hypogalactia mice. Additionally, puerarin increased the expression levels of β-casein, fatty acid synthase (FAS), and glucose transporter 1 (GLUT1). Mechanically, puerarin stimulated secretion of prolactin (PRL), estradiol (E2), and progesterone (P4) in agalactosis mice. Puerarin also substantially increased PRLR, JAK2, and STAT5a expression levels in postpartum hypogalactia mice.

Conclusion

This study suggested that puerarin may promote lactation by stimulating PRL secretion and activating the PRLR/JAK2/STAT5 signaling pathway.

Detection and quantification of miRNA 148a expression in infant formulas

MiRNA 148a, which is associated with various biological processes such as immunity and cell differentiation, is one of the most abundant miRNAs in breast milk. This study aimed to determine the amount of miRNA 148a in different infant formulas, which are used for infants who cannot receive breast milk. The study analyzed 20 formulas, including stage one infant formulas (0-6 months of age), stage two follow-up formulas (6-12 months of age), stage three toddler formulas (above 12 months of age), and premature ones, analyzing miRNA 148a expression and qPCR miRNA gene expression, with significance set at p < 0.05. The expression levels of miRNA 148a in different infant formulas were compared, and no statistically significant difference was observed (p > 0.05). Also, there was no difference in relative miRNA 148a expression across formulas with and without probiotics (p > 0.05). Protein levels in probiotic formulas (0 month-1 year+) were positively correlated with relative miRNA 148a expression (p = 0.022). Although miRNA 148a expression has been shown to be present in formulas, it has been revealed that the amount is low compared to breast milk in line with the literature. In this direction, it is important to increase current data on the mechanisms of action of miRNAs in breast milk and the efforts to ensure that infant formulas reach a composition closest to breast milk in line with their biological effects. PRACTICAL APPLICATION: The miRNAs found in exosomal compounds in human breast milk are very diverse in terms of number and health effects, and can control various biological processes in cells, including immunity, cell differentiation, and apoptosis. One of these is miRNA 148a, which is the most abundant in human breast milk. For this reason, in this study, the miRNA 148a content of infant formulas, which are commonly used in healthy babies who cannot receive enough human breast milk (breastfeeding recommended for at least 6 months and up to 2 years) for a valid reason, was analyzed. In conclusion, miRNA expression has been detected in infant formulas, but it has been shown that this expression is at a low level.

Association between breastfeeding duration and educational attainment in rural Southwest Uganda: a population-based cohort study

BACKGROUND

Breastfeeding is important for early childhood nutrition and health. The positive effects on educational outcomes may be attributed to socioeconomic factors. Socioeconomic status is not a strong predictor of breastfeeding in sub-Saharan African countries. Yet, few studies have investigated the association between breastfeeding and educational outcomes in these countries.

OBJECTIVE

This study investigated the association between breastfeeding duration and children's educational attainment in rural Southwest Uganda.

METHODS

We analysed longitudinal data on 3018 children who had information on breastfeeding and were followed for at least 5 years, with at least one primary school grade recorded by 2005. Data on breastfeeding duration were collected from mothers. The highest school grade was recorded repeatedly between ages 6 and 12 years. We calculated age-for-grade based on whether a child was on, over, or under the official age for a grade. Generalised estimating equations and binary logistic regression estimated the effect of breastfeeding duration on being 2 years, 3 or more years, or any years over-age for grade in primary school, adjusting for socioeconomic status and maternal-child characteristics.

RESULTS

Most mothers breastfed for more than a year. Just over one-third breastfed for 18-23 months, and 30% breastfed for longer. By age eight, 42% of the children were two years over-age for their grade. Three or more years over-age for grade increased from 19% at age nine to 56% at age 12. Both adjusted and unadjusted estimates were consistent in showing reduced odds for children being 2 years, 3 or more years, or any years over-age for grade among children breastfed for 7-12, 13-17, 18-23, and > 23 months compared to those breastfed for 0-6 months. There was no evidence to support an overall association between breastfeeding duration and being over-age for grade. There was no evidence of association in the sex and age sub-group analyses.

CONCLUSION

Although we found no association between breastfeeding duration and educational attainment, breastfeeding remains important for children's health and nutrition, and mothers should be encouraged and supported to breastfeed for the recommended duration.

Glycerol-3-phosphate activates ChREBP, FGF21 transcription and lipogenesis in Citrin Deficiency

Citrin Deficiency (CD) is caused by inactivation of SLC25A13, a mitochondrial membrane protein required to move electrons from cytosolic NADH to the mitochondrial matrix in hepatocytes. People with CD do not like sweets. We discovered that SLC25A13 loss causes accumulation of glycerol-3-phosphate (G3P), which activates carbohydrate response element binding protein (ChREBP) to transcribe FGF21, which acts in the brain to restrain intake of sweets and alcohol, and to transcribe key genes of de novo lipogenesis. Mouse and human data establish G3P-ChREBP as a new mechanistic component of the Randle Cycle that contributes to metabolic dysfunction-associated steatotic liver disease (MASLD) and forms part of a system that communicates metabolic states from liver to brain in a manner that alters food and alcohol choices. The data provide a framework for understanding FGF21 induction in varied conditions, suggest ways to develop FGF21-inducing drugs, and drug candidates for both lean MASLD and support of urea cycle function in CD.

The Refractive Index of Human Milk Serum: Natural Variations and Dependency on Macronutrient Concentrations

The refractive index (RI) of human milk serum (also known as whey, milk soluble fraction or milk plasma) depends on the individual molecular species dissolved in the serum and their concentrations. Although the human milk serum RI is known to influence milk analysis methods based on light scattering, the RI dependency on human milk serum composition is currently unknown. Therefore, we systematically evaluate how the RI depends on natural variations in macronutrient concentrations in the soluble fraction. We measure RI variations in serum simulating samples with controlled macronutrient concentrations, as well as skimmed and whole fore-, bulk, and hindmilk from 19 donors. For both types of samples, we relate the measured RI to the macronutrient composition. From the serum simulating samples, we observe that the RI depends more on variations in whey protein, than carbohydrate concentrations, while minerals have negligible influence. For all donated samples, the average RI was 1.3470 (range 1.3466-1.3474). Per donor, no significant differences were observed in RI between fore-, bulk, and hindmilk. We conclude that protein and solids-not-fat (i.e., the total contribution of carbohydrates, proteins and minerals present in milk) concentrations are most predictive for human milk serum RI.

Role of maternal milk in providing a healthy intestinal microbiome for the preterm neonate

The immature gastrointestinal tract of preterm neonates leads to a delayed and distinctive establishment of the gut microbiome, making them susceptible to potentially pathogenic bacteria and increasing the risk of infections. Maternal milk, recognized as the optimal source of nutrition, plays a multifaceted role in modulating the gut microbiome of premature newborns. Human milk oligosaccharides, acting as prebiotics, provide essential nourishment for key bacteria such as Bifidobacterium, contributing to the proliferation of beneficial bacterial populations. Additionally, maternal milk is rich in Immunoglobulins that stimulate immune cell responses, providing protective effects on the infant's gut mucosa. Moreover, bioactive proteins such as secretory immunoglobulin A (SIgA), lactoferrin, lysozyme, and mucins play a crucial role in defending against pathogens and regulating the immune system at the cellular level. These proteins contribute not only to infection prevention but also emphasize the impact of breast milk in fortifying the body's innate defenses. This multifaceted role of maternal milk, including essential nutrients, beneficial bacteria, and bioactive proteins, highlights the importance of promoting the mother's own milk feeding in the Neonatal Intensive Care Unit (NICU). It not only optimizes the long-term outcomes and well-being of preterm infants but also provides a holistic approach to their health and development. IMPACT: This article contributes to the current understanding of the relationship between breastfeeding and the intestinal microbiota. Fill gaps in existing literature about the subject. Provides new insights for future research.

Investigation of the gastric digestion behavior of commercial infant formulae using an in vitro dynamic infant digestion model

The gastric digestion behavior of different commercial Stage 1 infant formulae (for 0-6 months) with different formulation backgrounds was investigated using an in vitro dynamic infant human gastric simulator (iHGS). The microstructural arrangements of the protein and lipid, colloidal stability and protein hydrolysis during digestion were elucidated. During gastric digestion, casein-dominant formulations showed a higher extent of aggregation due to their high proportion of casein micelles that underwent coagulation upon acidification and via the action of pepsin. The extensive protein coagulation/curd formation in casein-dominant infant formulae slowed the rate of protein hydrolysis and resulted in the retention of caseins in the iHGS for longer times. Confocal micrographs showed that oil droplets were entrapped in the curd particles of casein-dominant infant formulae, which consequently slowed the gastric emptying of lipids. Conversely, whey-dominant formulations showed a lower degree of protein aggregation that resulted in faster protein hydrolysis and rapid protein and lipid emptying from the iHGS. It was also revealed that whey-dominant infant formulae in the presence of biopolymers increased the viscosity of gastric chyme and induced the flocculation of oil droplets. This altered the rate of protein hydrolysis and emptying of lipids. Correlation analyses depicted the overall kinetics of gastric emptying of macronutrients during digestion and comprised two stages: (i) driven by the continuous stomach emptying and (ii) influenced by aggregation and coalescence indices. The present study highlights the similarities and differences in the digestion behaviors of commercial infant formulae based on important ingredients such as types of proteins and biopolymers, regardless of the formulation or processing histories.

Determination of Minor and Trace Elements in Breast Milk of Lactating Mothers in Early Lactation from Tehran, Iran Using Neutron Activation Analysis Method

This study aimed to evaluate the concentrations of both essential and non-essential elements in the breast milk of lactating mothers from Tehran, Iran, during the colostrum period. Neutron activation analysis (NAA) was used to measure the element concentrations. Additionally, the study assessed how these element concentrations were influenced by maternal factors such as age and economic status. Breast milk samples were collected from 95 lactating mothers, aged 18 to 41, during the early lactation phase, specifically within the colostrum period (2-7 days postpartum). The colostrum milk samples were freeze-dried, powdered, and irradiated at the Tehran Research Reactor for neutron activation analysis (NAA). This method was used to measure the concentrations of essential elements-calcium (Ca), potassium (K), sodium (Na), chlorine (Cl), and iodine (I)-as well as non-essential elements-aluminum (Al), bromine (Br), and rubidium (Rb). Descriptive statistics, including mean, median, maximum, minimum, and standard deviation, were calculated for each element. Statistical analyses, such as Pearson's correlation, were performed to assess relationships between the concentrations of various elements. Additionally, t-tests and p-values were employed to evaluate differences in element levels across maternal age groups (17-34 years vs. 35-45 years) and economic status (high/middle vs. low). The mean concentrations of the elements in dry breast milk powder samples were: Al = 6.9 mg/kg, Br = 11.9 mg/kg, Ca = 2.757 mg/g, Cl = 7.836 mg/g, I = 1.22 mg/kg, K = 5.853 mg/g, Na = 4.932 mg/g, and Rb = 3.69 mg/kg. Significant correlations were found between element pairs, such as Na-Cl, Br-Cl, Na-Br, Rb-K, and I-Cl. Maternal age significantly influenced bromine concentrations, with older mothers showing 22% higher Br levels (p = 0.038), while calcium levels were 15% lower but not statistically significant (p = 0.20). Maternal economic status significantly impacted calcium and potassium concentrations, with higher levels observed in mothers from better economic conditions (p = 0.02 and p = 0.025, respectively). This study highlights the elemental composition of breast milk samples of lactating mothers in Tehran and shows that maternal factors, such as age and economic status, can significantly influence the concentrations of specific elements in breast milk.

"OMICS" in Human Milk: Focus on Biological Effects on Bone Homeostasis

Human milk (HM) is a complex biofluid rich in nutrients and bioactive compounds essential for infant health. Recent advances in omics technologies-such as proteomics, metabolomics, and transcriptomics-have shed light on the influence of HM on bone development and health. This review discusses the impact of various HM components, including proteins, lipids, carbohydrates, and hormones, on bone metabolism and skeletal growth. Proteins like casein and whey promote calcium absorption and osteoblast differentiation, supporting bone mineralization. Long-chain polyunsaturated fatty acids like docosahexaenoic acid (DHA) contribute to bone health by modulating inflammatory pathways and regulating osteoclast activity. Additionally, human milk oligosaccharides (HMOs) act as prebiotics, improving gut health and calcium bioavailability while influencing bone mineralization. Hormones present in HM, such as insulin-like growth factor 1 (IGF-1), leptin, and adiponectin, have been linked to infant growth, body composition, and bone density. Research has shown that higher IGF-1 levels in breast milk are associated with increased weight gain, while leptin and adiponectin influence fat mass and bone metabolism. Emerging studies have also highlighted the role of microRNAs (miRNAs) in regulating key processes like adipogenesis and bone homeostasis. Furthermore, microbiome-focused techniques reveal HM's role in establishing a balanced infant gut microbiota, indirectly influencing bone development by enhancing nutrient absorption. Although current findings are promising, comprehensive longitudinal studies integrating omics approaches are needed to fully understand the intricate relationships among maternal diet, HM composition, and infant bone health. Bridging these gaps could offer novel dietary strategies to optimize skeletal health during infancy, advancing early-life nutrition science.

Informing the risk assessment related to lactation and drug exposure: A physiologically based pharmacokinetic lactation model for pregabalin

Breastfeeding is important in childhood development, and medications are often necessary for lactating individuals, yet information on the potential risk of infant drug exposure through human milk is limited. Establishing a lactation modeling framework can advance our understanding of this topic and potentiate clinical decision making. We expanded the modeling framework previously developed for sotalol using pregabalin as a second prototypical probe compound with similar absorption, distribution, metabolism, and elimination (ADME) properties. Adult oral models were developed in PK-Sim® and used to build a lactation model in MoBi® to simulate drug transfer into human milk. The adult model was applied to breastfeeding pediatrics (ages 1 to 23 months) and subsequently integrated with the lactation model to simulate infant drug exposure according to age, size, and breastfeeding frequency. Physiologically based pharmacokinetic (PBPK) model simulations captured the data used for verification both in adults and pediatrics. Lactation simulations captured observed milk and plasma data corresponding to doses of 150 mg administered twice daily to lactating individuals, and estimated a relative infant dose (RID) of approximately 7% of the maternal dose. The infant drug exposure simulations showed peak plasma concentrations of 0.44 μg/mL occurring within the first 2 weeks of life, followed by gradual decline with age after week four. The modeling framework performs well for this second prototypical drug and warrants expansion to other drugs for further validation. PBPK modeling and simulation approaches together with clinical lactation data could ultimately help inform infant drug exposure risk assessments to guide clinical decision making.

Intestinal gluconeogenesis controls the neonatal development of hypothalamic feeding circuits

OBJECTIVE

Intestinal gluconeogenesis (IGN) regulates adult energy homeostasis in part by controlling the same hypothalamic targets as leptin. In neonates, leptin exhibits a neonatal surge controlling axonal outgrowth between the different hypothalamic nuclei involved in feeding circuits and autonomic innervation of peripheral tissues involved in energy and glucose homeostasis. Interestingly, IGN is induced during this specific time-window. We hypothesized that the neonatal pic of IGN also regulates the development of hypothalamic feeding circuits and sympathetic innervation of adipose tissues.

METHODS

We genetically induced neonatal IGN by overexpressing G6pc1 the catalytic subunit of glucose-6-phosphatase (the mandatory enzyme of IGN) at birth or at twelve days after birth. The neonatal development of hypothalamic feeding circuits was studied by measuring Agouti-related protein (AgRP) and Pro-opiomelanocortin (POMC) fiber density in hypothalamic nuclei of 20-day-old pups. The effect of the neonatal induction of intestinal G6pc1 on sympathetic innervation of the adipose tissues was studied via tyrosine hydroxylase (TH) quantification. The metabolic consequences of the neonatal induction of intestinal G6pc1 were studied in adult mice challenged with a high-fat/high-sucrose (HFHS) diet for 2 months.

RESULTS

Induction of intestinal G6pc1 at birth caused a neonatal reorganization of AgRP and POMC fiber density in the paraventricular nucleus of the hypothalamus, increased brown adipose tissue tyrosine hydroxylase levels, and protected against high-fat feeding-induced metabolic disorders. In contrast, inducing intestinal G6pc1 12 days after birth did not impact AgRP/POMC fiber densities, adipose tissue innervation or adult metabolism.

CONCLUSION

These findings reveal that IGN at birth but not later during postnatal life controls the development of hypothalamic feeding circuits and sympathetic innervation of adipose tissues, promoting a better management of metabolism in adulthood.