Breast Milk Research Articles

Parenteral nutrition dependence and growth in pediatric patients with intestinal failure following transition to blenderized tube feedings: A case series.

Human milk and amino acid (AA) formulas are correlated with a shorter duration of parenteral nutrition (PN) dependence for infants with intestinal failure (IF). Literature to guide feeding practices beyond infancy in this population is limited. We aimed to assess PN dependence, growth patterns, and stool frequency in pediatric patients with IF who transitioned from AA or hydrolyzed formula to blenderized tube feedings (BTFs). We performed a retrospective review among children with IF observed at Boston Children's Hospital from January 2014 to January 2019. Inclusion criteria were receipt of BTF for ≥3 months at a volume of ≥200 ml/day and ≥2 outpatient visits during the study period. Patients who received BTF in combination with another formula or food purees were excluded. Twelve children met criteria. Eleven had a small bowel resection with mean residual small bowel length of 51 ± 47 cm. Two retained their ileocecal valve (ICV), and eight had colonic resection. All patients were dependent on PN with mean (SD) energy intake of 51 ± 21 kcal/kg/day. After transition to BTF, three patients (25%) achieved enteral autonomy, and seven (58%) had a reduction in PN energy intake. Anthropometric data and stool frequency were generally unchanged. The transition from AA or hydrolyzed formula to BTF was associated with a substantial reduction in PN support in 12 children with IF. Stool frequency and growth parameters were not significantly changed. Our findings suggest that the use of BTF in older children with IF should be considered.

Mothers' and fathers' experiences of breastfeeding and returning to paid work after birth: A mixed-method study.

This mixed-method study explored the experiences of mothers and fathers combining breastfeeding with returning to paid employment after childbirth. Tasmanian State Service employees participated in an online survey and phone interviews. A total of 130 parents completed the survey, and 42 participated in 60-min phone interviews. The survey had more female respondents (109) than male (21), and only 4 of the 42 interviews were with fathers. The sample consisted mainly of professional women (84%) and men (16%), predominantly Australian-born (88%). Two-thirds of participants worked part-time (62%), taking either unpaid (52%) or paid leave (61%) within the first 12 months after birth. The majority (88%) preferred to breastfeed, with the mean age of the first formula feed being 4.1 months. A narrative analysis of the qualitative data, informed by work-family conflict theory, reveals that transitioning back to paid work while breastfeeding is challenging for both mothers and fathers. Parents face multiple conflicts between paid work, family responsibilities and maintaining breastfeeding. The emotional and physical demands of feeding, expressing, storing and transporting breast milk, combined with often inadequate workplace facilities, policies and gender discrimination, add to parental pressure. Mothers bear the greatest burden, while fathers' roles and needs are often overlooked in the workplace. The major finding of this study is that breastfeeding is insufficiently recognised as an integral part of the return-to-work process for both parents, generating a form of work-family breastfeeding conflict, where work (part-time or full-time) interferes with family responsibilities and breastfeeding. Family-friendly breastfeeding policies based on equity principles are needed to address workplace gender inequality and discrimination and better support parents in combining work and breastfeeding.

Biological effects of combinations of structurally diverse human milk oligosaccharides

Human milk oligosaccharides (HMOs) are a diverse group of structures and an abundant bioactive component of breastmilk that contribute to infant health and development. Preclinical studies indicate roles for HMOs in shaping the infant gut microbiota, inhibiting pathogens, modulating the immune system, and influencing cognitive development. In the past decade, several industrially produced HMOs have become available to fortify infant formula. Clinical intervention trials with manufactured HMOs have begun to corroborate some of the physiological effects reported in preclinical studies, especially modulation of the gut microbiota in the direction of breastfed infants. As more HMOs become commercially available and as HMOs have some shared mechanisms of action, there is a need to better understand the unique and differential effects of individual HMOs and the benefits of combining multiple HMOs. This review focuses on the differential effects of different HMO structural classes and individual structures and presents a scientific rationale for why combining multiple structurally diverse HMOs is expected to exert greater biological effects.

Population pharmacokinetic modelling of cetirizine concentrations in human breast milk-A contribution from the ConcePTION project.

Cetirizine is an antihistamine commonly used to treat allergic rhinitis and other allergic conditions. Cetirizine is often prescribed to breastfeeding mothers although there is limited information on infant exposure via breast milk. The aim of this study was to develop a popPK model based on data from a lactation study to predict cetirizine breast milk concentrations and estimate the relative infant dose (RID) in a breastfed infant. A popPK model was developed in NONMEM on data from a human lactation study including 35 women using cetirizine or levocetirizine while breastfeeding. Serial samples of breast milk were collected (n = 205) and the cetirizine concentrations quantified using a validated LC-MS/MS method. A one-compartment model of cetirizine in breast milk was developed and employed to calculate the relative infant dose (RID). Covariates related to the maternal characteristics and breastfeeding patterns were evaluated in the model; only milk sampling pumping duration was found to be a significant covariate, with an increasing pumping duration leading to an increased apparent milk volume of distribution (Vm). The mean RID was 1.99% with the highest RID being 3.36% at Cmax. PopPK modelling could be used to estimate infant exposure to cetirizine via breast milk. The low predicted exposure in infants supports that cetirizine is compatible with breastfeeding.

Impact of Oxytocin Massage for Postpartum Mothers on Breast Milk Production

Introduction Mother's Milk is a divine gift explained in the Quran, Surah Lukman verse 14, which recommends mothers to breastfeed their children for a full two years. Breast milk is considered the best source of nutrition for infants, especially within the age range of 0–6 months. However, not all breastfeeding mothers can easily produce breast milk directly, as the process involves a complex interaction influenced by the hormone oxytocin. This study aims to assess the impact of applying oxytocin massage on breast milk production in postpartum mothers in the Working Area of Waimital Community Health Center, Kairatu District, West Seram Regency. The research design used is quasi-experimental, with sample selection using non-probability sampling involving 20 respondents. The research instrument used a questionnaire, and data analysis was conducted using the Mann-Whitney test and Wilcoxon test to evaluate changes before and after the intervention for each variable. The bivariate analysis results based on the treatment group variable showed the highest P-value at 0.008 and the lowest at 0.003 (< 0.05), while in the control group, the highest P-value was 0.157 and the lowest was 0.083 (< 0.05). Thus, it can be concluded that the application of oxytocin massage has a highly significant effect on breast milk production in postpartum mothers in the treatment group.

Understanding the influence of Manasika Bhavas on Stanya Kshaya: A Conceptual Study

Breast milk stands as the foremost source of nutrition in every individual's early life. According to Ayurveda, Stanya is considered an Upadhatu of Rasa and is pivotal for the nourishment and development of infants. Ayurveda defines decreased breast milk or lactation insufficiency as Stanya Kshaya, primarily attributed to emotions like anger, grief, and excessive affection, alongside dietary influences. Psychological factors such as emotional stress, anxiety, and maternal health also significantly impact milk production, necessitating both psychological and medical interventions. Any disruption in Agni affects Ahara Rasa, leading to disturbances in Rasa Dhatu, thereby affecting Stanya. Psychological aspects play a crucial role in the proper formation of Ahara Rasa. The significance of Manasika Bhavas lies in their advocacy of Soumanasya as a primary treatment for Ksheerajanana. This paper explores the correlation between psychological well-being and lactation outcomes, drawing on both contemporary psychological research and traditional Ayurvedic principles. Psychological stress, anxiety, depression, and maternal bonding are examined as key factors affecting hormonal balance and neuroendocrine pathways involved in lactation. Understanding these influences is crucial for holistic approaches to maternal health and breastfeeding support. The integration of psychological interventions alongside conventional medical treatments could enhance maternal lactation success rates and overall maternal-infant health outcomes. Thus, managing Stanya Kshaya requires thorough consideration of both psychological factors and dietary practices.

Controllable Enzymatic Synthesis of Natural Asymmetric Human Milk Oligosaccharides

Controllable Enzymatic Synthesis of Natural Asymmetric Human Milk Oligosaccharides

1H NMR-Based Metabolomic Profiling and Comparison of Human Milk Across Different Lactation Stages in Secretors and Non-Secretors: A Study of Chinese Lactating Women

BackgroundHuman milk oligosaccharides (HMOs) and other milk-derived metabolites are crucial for infant health, influencing gut microbiota and overall development. ObjectiveThis study aims 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. MethodsAn exploratory cross-sectional study was designed to compare the levels of HMOs and non-HMOs metabolites in milk samples from 129 lactating Chinese women within 1 year 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 influence of delivery mode and infant sex on milk metabolite composition were explored. ResultsUniform Manifold Approximation and Projection (UMAP) analysis of HMOs profiles revealed distinct clustering based on Se status, with significant differences in 2'-FL and 3-FL levels observed between Se+ and Se- groups. A decreasing trend for 2'-FL and 6-’SL levels, along with an increase in 3-FL levels, was observed with increasing lactating period within 12 months postpartum. Non-HMOs metabolite analysis indicated that Se status only affected glutamate levels. An increase in glutamine levels was observed 3–9 months postpartum. A continuous increase in o-phosphocholine levels was noted in 12 months postpartum, along with reductions in citrate and sn-glycero-phosphocholine levels. Delivery mode and infant sex did not affect both HMOs and non-HMOs levels. ConclusionsMetabolomic 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 levels were also observed over the one year 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.

Human milk fat globule size distributions: comparison between laser diffraction and 3D confocal laser scanning microscopy

Milk fat globules (MFGs) in human milk provide energy to breastfed infants and support infant development. Accurate measurements of MFG size distributions are important to better understand MFG function and origin, as well as the influence of MFG size on milk composition analysis methods. Nevertheless, commonly used laser diffraction systems have never been thoroughly validated for size distribution measurements in human milk. Here, we introduce a new method for determining the size distribution of milk fat globules in human milk, using 3D confocal laser scanning microscopy (CLSM) in combination with fluorescent labeling of MFGs. We validate and compare 3D CLSM to laser diffraction (Mastersizer 2000, Malvern Panalytical), using polystyrene microsphere size standards. Next, we apply both methods to evaluate MFG size distributions in human milk. We show that 3D CLSM can be used to obtain more accurate size distributions between 500 nm and 10 μm compared to laser diffraction. Importantly, MFG size distributions obtained with 3D CLSM contain no secondary population around 1 μm, in contrast to laser diffraction measurements. This suggests that the bimodal MFG distribution obtained by laser diffraction can be an artifact of the built-in fitting algorithm, instead of an actual feature of human milk. This work demonstrates that care should be taken when interpreting size distributions of MFGs measured with laser diffraction and that 3D CLSM is an accurate alternative for measuring size distributions in lactation and dairy research.

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.

Allomilk: An Anthropogeny-Based Framework for Human Milk as a Climate Solution.

Climate change is an urgent threat to perinatal and infant health, with the greatest effects of climate change exposures being felt disproportionately by global majority communities who have been most harmed by systems of oppression. Human milk feeding is one recognized solution to bolster climate resilience. Yet, policies and practices to support human milk as a climate solution are inconsistent and under-prioritized, which is unsurprising given the lack of alignment between human history and current cultural context with regard to lactation and human milk access. This paper presents a new framework on lactation as a climate solution, which is unique in its incorporation of the critical history of cooperative breastfeeding in our species. Rooted in anthropogeny, or the study of human origins, and antiracist principles of lactation, the Allomilk Framework highlights five concepts of the ideal application of human milk as a climate solution, bridging ancient allonursing with present-day lactation and human milk access. These ideal applications-and the proposed development of measures to operationalize them-will advance the field through a shared understanding of the qualities that should be prioritized in the assessment of policies and practices at the intersection of climate resilience and human milk access. Application of the Allomilk Framework to assess and design future policies and practices will advance the field by increasing the potential for climate resilience and climate mitigation while working with-rather than against-the importance of cooperative breastfeeding in human history.

Isolation and characterization of Bifidobacterium spp. From breast milk with different human milk oligosaccharides utilization and anti-inflammatory capacity

Breast milk is the best source of nutrition for infants. Human milk oligosaccharides (HMOs) and the corresponding HMOs-consuming Bifidobacterium positively influence infant health. This study aims to isolate and characterize Bifidobacterium from breast milk of healthy Chinese mothers, identifying the most efficacious strains for inclusion in simulated maternal milk formulas. Nine Bifidobacterium strains (two of B. breve and seven of B. infantis) were isolated, exhibiting a broad spectrum of probiotic potential. This included tolerance to simulated infant gastrointestinal conditions, notable adhesion, antibacterial, antioxidant activities, and HMOs utilization ability. Lacto-N-Tetraose (LNT) is preferred in early growth among Bifidobacterium isolates. B. breve showed a preference for LNT, whereas B. infantis showed a preference for fucosylated HMOs, and displayed reduced utilization of sialylated HMOs. They also exhibited robust safety profiles, including no hemolytic activity, an appropriate D/L lactate-producing ratio, and non-toxicity in an acute oral toxicity assay on mice. It is noteworthy that B. breve N-90, O-147, B. infantis O-161 and R-1 exhibited anti-inflammatory effects in LPS-induced RAW 264.7 cells. Specifically, a notable reduction in TNF-α levels was observed in pre-treatment, while a decrease in IL-1β and IL-6 levels in co-treatment. B. breve N-90 and B. infantis R-1 were identified finally as promising probiotic candidates. Their whole-genome sequencing analysis confirmed presence of functional genes associated with gastrointestinal colonization, antioxidation, and glycoside hydrolase activity on HMOs. The annotation for antibiotic resistance and virulence genes concurred with phenotypes, further validating the safety. Breast milk is a good source for Bifidobacteria isolation, while Bifidobacteria utilize HMOs in a strain-dependent manner. The two selected strains, B. breve N-90 and B. infantis R-1, are potential candidates for inclusion in simulated maternal milk formulas and deserved further in vivo investigation for their health-promoting effects.

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 1mL 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 (-/+ 1SD) 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 intra-individual coefficient of variation (%CV) was 32% and 12% for vitamin D3 and 25(OH)D3, respectively. 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.

Probiotic and Functional Characterization of Newly Isolated Lactiplantibacillus plantarum Strains from Human Breast Milk and Proliferative Inhibition Potential of Metabolites

Four Lactiplantibacillus plantarum strains newly isolated and identified from human breast milk in Turkey, have probiotic, functional and proliferative inhibition potential of metabolites against colon cancer cell lines (Caco-2 and HT-29) were evaluated. In simulated gastric (pH+pepsin) and intestinal (bile and pancreatin) media, all strains exhibited strong probiotic character by showing resistance, although decreasing with time and concentration. The strains were sensitive to penicillin G, rifampin and chloramphenicol and showed antibacterial effect on all pathogenic bacteria. Citric acid, malic acid, tartaric acid, pyruvic acid and fumaric acid were not detected in the strains, while the highest amount of acetic acid was detected. It was observed that all strains synthesized exopolysaccharide in similar amounts. Compared to standard antioxidants, the strains showed less DPPH activity and similar ABTS activity. High amounts of metabolites of the strains showed good antiproliferative effect on Caco-2, while lower amounts showed good antiproliferative effect on the HT-29 cell line. When all the data were considered, it was determined that the strains were close to each other, but the YAAS 23 strain showed slightly better properties. In conclusion, breast milk is a unique environment harboring beneficial bacteria such as L. plantarum for human health.

Breast milk oligosaccharides are the most essential ingredient in breast milk, affecting the health of infants: A review

Breastfeeding remains the “gold standard” of nutrition for children in the first years of life. However, factors such as hypogalactia, maternal stress, health problems and simply an unwillingness to breastfeed deprive the baby of breast milk (BM) and challenge pediatricians to choose an alternative food for the baby. The BM composition is complex, dynamic, and of scientific interest, and the attention of most scientists is directed to BM oligosaccharides (BMOs). Many benefits of BMOs have been proven in relation to the child's health, including the formation of the intestinal microbiota, maturation of the immune response, contribution to the barrier function of the intestine, and protection against pathogens. In the absence of breastfeeding, modern formulas containing BMOs can be used. The addition of a combination of 5 BMOs is a promising and effective approach to maintaining the overall health of formula-fed infants.

Proteome characterization of extracellular vesicles from human milk: Uncovering the surfaceome by a lipid-based protein immobilization technology.

Breast milk is an essential source of nutrition and hydration for the infant. In addition, this highly complex fluid is rich in extracellular vesicles (EVs). Here, we have applied a microfluidic technology, lipid-based protein immobilization (LPI) and liquid chromatography with tandem mass spectrometry (LC-MS/MS) to characterize the proteome of human milk EVs. Mature milk from six mothers was subjected to EV isolation by ultracentrifugation followed by size exclusion chromatography. Three of the samples were carefully characterized; suggesting a subset enriched by small EVs. The EVs were digested by trypsin in an LPI flow cell and in-solution digestion, giving rise to two fractions of peptides originating from the surface proteome (LPI fraction) or the complete proteome (in-solution digestion). LC-MS/MS recovered peptides corresponding to 582 proteins in the LPI fraction and 938 proteins in the in-solution digested samples; 400 of these proteins were uniquely found in the in-solution digested samples and were hence denoted "cargo proteome". GeneOntology overrepresentation analysis gave rise to distinctly different functional predictions of the EV surfaceome and the cargo proteome. The surfaceome tends to be overrepresented in functions and components of relevance for the immune system, while the cargo proteome primarily seems to be associated with EV biogenesis.

Problematic issues of the impact of microplastics on the human body and the environment: A review

Currently, the widespread use of plastic has become a serious problem for the environment and human health. Microplastics, being an artificial polymer created by man, are highly resistant to external influences and their decomposition requires a significant amount of time. The article provides information on the distribution of microplastics and their impact on the environment and the human body, issues of detecting microplastics in the blood, heart, lungs, placenta and meconium, in breast milk, hypothetical mechanisms by which microplastics penetrate into human tissues and the metabolism of plasticizers in children with autism spectrum disorder and attention deficit hyperactivity disorder. In the modern world, plastic has become an integral part of our daily lives, the presence of microplastics in plastic bags for storing breast milk, in baby formula and polypropylene bottles has been demonstrated, the relationship between microplastics and postpartum depression, the relationship between fecal microplastics and the status of inflammatory bowel diseases has been described. Making the decision to limit the use of plastic products in your home is an important step that can play a key role in reducing environmental pollution and protecting the health of future generations.

The prospective associations of fetal growth-related pregnancy complications with subsequent breastfeeding duration and markers of human milk production.

The development of the breast for lactation occurs throughout pregnancy. It is unknown whether pregnancy complications resulting in poor fetal growth can affect breastfeeding success. We examined whether fetal growth-related pregnancy complications were associated with earlier breastfeeding cessation and changes in the concentrations of human milk biomarkers of low milk production. We used data from the Growing Up in Singapore Toward healthy Outcomes (GUSTO) study (n=954). Human milk concentrations of protein, lactose, citrate, sodium, potassium and zinc at 3 weeks postpartum were available for 180 mother-infant dyads. We examined the associations of fetal growth measures, including term infants born small-for-gestational-age (SGA) (<10th percentile), pregnancies complicated by fetal growth deceleration (FGD) (2nd - 3rd trimester fetal growth dropped between major centiles), elevated umbilical artery resistance (UAR) (> 90th percentile) or hypertensive disorders of pregnancy (HDP) with (i) risk of ceasing breastfeeding (Cox regression) and (ii) concentrations of human milk components (weighted linear regression). Adjusting for maternal education, smoking exposure, breastfeeding intentions and pre-pregnancy BMI, individuals who delivered SGA infants, and those with HDP were more likely to breastfeed for a shorter duration when compared to those with uncomplicated pregnancies (adjusted hazard ratio [95% CI]: 1.45 [1.11, 1.89] and 1.61 [1.14, 2.29], respectively); associations were not significant for FGD and UAR. SGA was not associated with concentrations of human milk biomarkers, but compared to participants with uncomplicated pregnancies, milk produced by those with HDP contained lower zinc concentrations (adjusted beta coefficient [95% CI]: -0.56 mg/L [-1.08, -0.04]). Individuals with HDP and those with SGA infants tend to breastfeed for a shorter duration; however, only HDP appeared to be associated with biomarkers of compromised milk production. Further research and support are needed to help individuals with HDP and SGA achieve their breastfeeding goals. This study was registered as NCT01174875, and can be accessed at https://clinicaltrials.gov/study/NCT01174875.

Contents of linoleic acid, &amp;alpha;-linolenic acid and their ratio in human milk, influence factors, and effects on infant health

Contents of linoleic acid, <em>&amp;alpha;</em>-linolenic acid and their ratio in human milk, influence factors, and effects on infant health

Metabolomics reveals changes in levels of fecal branched chain amino acids and organic acids in very preterm infants fed human milk fortified with bovine colostrum

Background & aimsHuman milk is the optimal diet for very preterm infants (VPIs), but it requires nutrient fortification to support growth. Bovine colostrum (BC), rich in intact proteins and bioactive components, could serve as a novel fortifier with potential benefits to VPIs gut health. To evaluate a possible effect of feeding BC on intestinal metabolism, the gut microbiota, and their interaction, we studied the fecal metabolome of VPIs in the first month of life, as compared with a conventional fortifier (CF, based on infant formula ingredients). MethodsFecal samples were collected from VPIs recruited to the FortiColos trial (NCT03537365, BC, n = 107; CF, n = 112) before (FT0) and one (FT1) or two (FT2) weeks after start of fortification and analyzed using 1H NMR spectroscopy. Abundances of metabolites were compared between BC versus CF groups. Further, temporal changes in metabolite levels after start of fortification, as well as correlations with specific gut bacterial genera were explored. ResultsInfants in the BC group had higher levels of fecal acetoacetate, choline, methanol, uracil, creatine, creatinine, lysine and a lower leucine at both FT1 and FT2, relative to the CF group. Asparagine, tryptophan and phenylalanine levels were higher, and butyrate was lower in the BC group at FT1. At FT2, higher fecal succinate and lower isoleucine were found in the BC group. In addition, eight metabolites (asparagine, phenylalanine, tryptophan, lysine, creatinine, acetoacetate, methanol and uracil) had fortification-specific changes over time. Correlations were found between succinate and unclassified Enterobacteriaceae, butyrate and Clostridium, uracil and Staphylococcus, as well as unclassified Enterobacteriaceae members. ConclusionOur study shows distinct fecal metabolome profiles in VPIs in the first weeks after fortification with BC versus CF. The fortification- and time-specific gut metabolite changes suggest that fortifiers influence luminal nutrient metabolism and microbiota activity in VPIs. Fortifier type for human milk affected gut health of VIPs via altered gut metabolite levels, interacting with microbiota in VPIs.