Bioactive components in human milk are differentially associated with rates of lean and fat mass deposition in infants of mothers with normal vs. elevated BMI

Plasma and breast milk adipokines in women across the first year postpartum and their association with maternal depressive symptoms and infant neurodevelopment: Protocol for the APPLE prospective cohort study

INTRODUCTION

Adiponectin and leptin play important roles in the central nervous system. During the postpartum period, there is a need for a better understanding of the relationship between these cytokines and the neurological development of the infant, as well as their influence on preventing maternal depressive symptoms.

OBJECTIVES

To assess the correlation between adiponectin and leptin in maternal plasma and breast milk and their association with: infant neurodevelopment at 6 and 12 months of age; and maternal mental health over the first year postpartum.

METHODS

Prospective cohort study with four follow-up. Mothers and their newborns are recruited within the first 15 days postpartum (baseline). Follow-up visits occur at 2, 6, and 12 months postpartum. Visits include blood and breast milk collection, application of the Edinburgh Postnatal Depression Scale and Beck Depression Inventory to assess maternal mental health, application of the Bayley-III scale for infant developmental assessment, maternal and infant anthropometry and body composition, evaluation of reproductive history, mother-infant bonding, breastfeeding, consumption of ultra-processed foods, sleep quality, and socio-economic and demographic data.

RESULTS

The research received funds in August 2022, and participant recruitment began in September 2022. The sample size will consist of 95 mother-child pairs. As of September 2023, 68 participants have been recruited.

CONCLUSION

The project will provide insights into the association between adiponectin and leptin with postpartum depression and infant neurodevelopment, ultimately promoting improved care and quality of life for these groups. Additionally, it will provide data on the type of delivery, infant physical growth, maternal and infant body composition changes, sleep quality, consumption of ultra-processed foods, and maternal metabolic health, including vitamin D metabolites, oxidized polyunsaturated fatty acid metabolites, phospholipid species and triacylglycerols, which are of significant relevance to public health and, when interconnected, may yield important results and contribute to the existing literature.

TRIAL REGISTRATION

Name of the registry: Brazilian Clinical Trials Registry (ReBec). Registration number: RBR-9hcby8c.

Role of the biological active components of human milk on long-term growth and neurodevelopmental outcome

Human Milk is the best option for infant feeding; and for this reason, it should be promoted, protected, and supported. HM is an individual-specific-dynamic biofluid, characterized by an extreme variability in its composition. A wealth of literature has investigated how HM is related to healthy development. An association between HM composition, including nutrients and growth-related hormones as well as other bioactive components, and short-term and long-term infant outcomes could support this statement; however, the evidence is limited. In fact, HM composition is difficult to examine as it is dynamic and changes within a single feed, diurnally, according to stage of lactation and between and within populations. The aim of this review is summarizing only the innovative knowledge on the association between HM composition and long-term outcomes: infant growth and neurodevelopment. In this specific contest, macronutrients and historical biological component with well recognized effect were excluded (i.e. LCPUFA, DHA, iodine). Revised articles have been found in MEDLINE using breast milk-related outcomes, neurodevelopment, infant growth, breast milk-related biological factors, biomarkers, biological active components, and constituents as keywords. Moreover, we focus our search on the latest research results.

NR2F2 Reactivation in Early-life Adipocyte Stem-like Cells Rescues Adipocyte Mitochondrial Oxidation

In humans, perinatal exposure to an elevated omega-6 (n6) relative to omega-3 (n3) Fatty Acid (FA) ratio is associated with the likelihood of childhood obesity. In mice, we show perinatal exposure to excessive n6-FA programs neonatal Adipocyte Stem-like cells (ASCs) to differentiate into adipocytes with lower mitochondrial nutrient oxidation and a propensity for nutrient storage. Omega-6 FA exposure reduced fatty acid oxidation (FAO) capacity, coinciding with impaired induction of beige adipocyte regulatory factors PPARγ, PGC1α, PRDM16, and UCP1. ASCs from n6-FA exposed pups formed adipocytes with increased lipogenic genes in vitro, consistent with an in vivo accelerated adipocyte hypertrophy, greater triacylglyceride accumulation, and increased % body fat. Conversely, n6-FA exposed pups had impaired whole animal 13C-palmitate oxidation. The metabolic nuclear receptor, NR2F2, was suppressed in ASCs by excess n6-FA intake preceding adipogenesis. ASC deletion of NR2F2, prior to adipogenesis, mimicked the reduced FAO capacity observed in ASCs from n6-FA exposed pups, suggesting that NR2F2 is required in ASCs for robust beige regulator expression and downstream nutrient oxidation in adipocytes. Transiently re-activating NR2F2 with ligand prior to differentiation in ASCs from n6-FA exposed pups, restored their FAO capacity as adipocytes by increasing the PPARγ-PGC1α axis, mitochondrial FA transporter CPT1A, ATP5 family synthases, and NDUF family Complex I proteins. Our findings suggest that excessive n6-FA exposure early in life dampens an NR2F2-mediated induction of beige adipocyte regulators, resulting in metabolic programming that is shifted towards nutrient storage.

The association between maternal factors and milk hormone concentrations: a systematic review

Background

Breast milk is the gold standard for infant feeding. It is a dynamic biological fluid rich in numerous bioactive components. Emerging research suggests that these components, including hormones, may serve as signals between mother and offspring. From an evolutionary perspective, maternal hormonal signals could allow co-adaptation of maternal and offspring phenotype, with implications for their Darwinian fitness. However, a series of steps need to be considered to establish the role of a component as a signal and this systematic review focuses on one step: 'Do maternal factors influence the concentration of milk hormones?'

Objective

To systematically review human studies which analyze the association between maternal factors and the concentration of hormones in breast milk.

Methods

Three databases were searched for studies reporting the association of maternal factors including body mass index (BMI), weight, fat mass, age, ethnicity, smoking with hormones such as adiponectin, leptin, insulin, ghrelin, and cortisol in breast milk.

Results

Thirty-three studies were eligible for inclusion. Maternal BMI was positively associated with milk leptin (20/21 studies) and with milk insulin (4/6 studies). Maternal weight also displayed a positive correlation with milk leptin levels, and maternal diabetes status was positively associated with milk insulin concentrations. Conversely, evidence for associations between maternal fat mass, smoking, ethnicity and other maternal factors and hormone levels in breast milk was inconclusive or lacking.

Conclusion

Current evidence is consistent with a signaling role for leptin and insulin in breast milk, however other steps need to be investigated to understand the role of these components as definitive signals. This review represents a first step in establishing the role of signaling components in human milk and highlights other issues that need to be considered going forward.

Association Between Pro-inflammatory Cytokine Levels (IL-1β, IL-6, and TNF-α) in Human Colostrum and Maternal Body Composition Components

Background: Obesity is characterized as a low-grade chronic inflammatory state, marked by elevated inflammatory biomarkers. Breast milk (BM) is rich in nutritional elements, vitamins, minerals, immunological factors, and bioactive components. These bioactive components, capable of influencing biological processes, may vary in concentration based on maternal body composition. Research Aim/Question(s): This study aimed to explore the association between pro-inflammatory cytokine levels (interleukin-1 beta [IL-1β], interleukin-6 [IL-6], and tumor necrosis factor-alpha [TNF-α]) in human colostrum and maternal body composition, as analyzed through bioelectrical impedance vector analysis (BIVA). Method: In this cross-sectional study, 117 healthy postpartum participants were included, with each group (normal weight, overweight, and obese) comprising 39 individuals, as classified by BIVA. Colostrum samples were collected within the first 24 hours postpartum. Results: IL-1β levels did not significantly differ across the groups, with concentrations of 69.5 ± 103 pg/mL in normal-weight, 79.7 ± 97.9 pg/mL in overweight, and 68.7 ± 108 pg/mL in obese women. IL-6 levels were significantly higher in the overweight group (55 ± 72.4 pg/mL) than in the normal-weight (48.1 ± 74.1 pg/mL) and obese groups (28.9 ± 36.2 pg/mL) (p = 0.02). Similarly, TNF-α levels were higher in the overweight group, with concentrations of 58.7 ± 74.9 pg/mL, than in the normal-weight group, with concentrations of 38.6 ± 95.4 pg/mL, and 52.6 ± 115 pg/mL in obese women (p = 0.02). Conclusion: This study shows that IL-6 and TNF-α concentrations were statistically higher in the colostrum of overweight women, suggesting that maternal body composition may influence the inflammatory profile of BM.

Long-term health risk of offspring born from assisted reproductive technologies

Since the world's first in vitro fertilization baby was born in 1978, there have been more than 8 million children conceived through assisted reproductive technologies (ART) worldwide, and a significant proportion of them have reached puberty or young adulthood. Many studies have found that ART increases the risk of adverse perinatal outcomes, including preterm birth, low birth weight, small size for gestational age, perinatal mortality, and congenital anomalies. However, data regarding the long-term outcomes of ART offspring are limited. According to the developmental origins of health and disease theory, adverse environments during early life stages may induce adaptive changes and subsequently result in an increased risk of diseases in later life. Increasing evidence also suggests that ART offspring are predisposed to an increased risk of non-communicable diseases, such as malignancies, asthma, obesity, metabolic syndrome, diabetes, cardiovascular diseases, and neurodevelopmental and psychiatric disorders. In this review, we summarize the risks for long-term health in ART offspring, discuss the underlying mechanisms, including underlying parental infertility, epigenetic alterations, non-physiological hormone levels, and placental dysfunction, and propose potential strategies to optimize the management of ART and health care of parents and children to eliminate the associated risks. Further ongoing follow-up and research are warranted to determine the effects of ART on the long-term health of ART offspring in later life.

The association between human milk fatty acid composition in mothers with an elevated body mass index and infant growth changes

BACKGROUND & AIMS

Few studies have investigated alternations in human milk polyunsaturated fatty acid (PUFA) composition in the context of maternal obesity and its effects on infant growth trajectories. This study explored whether maternal weight status and breastfeeding type influence human milk FA composition and infant anthropometry during the first six months of life.

METHODS

Mother-infant dyads were enrolled from the Prediction of Allergies in Taiwanese Children birth cohort study. Data concerning maternal pre-pregnancy weight, infants' breastfeeding practices, and anthropometric data were obtained regularly. We identified and compared between the composition of 30 FAs in the colostrum and 2-month milk, respectively, in obese/overweight (OB/OW) and normal-weight (NW) mothers. Multiple linear regression analyses were performed to determine the association between PUFA composition at different lactation stages and infant anthropometric parameter changes and to identify the independent variables for body mass index (BMI) z-scores by six months of age.

RESULTS

We included 338 mother-infant dyads (OB/OW mothers, 16.9 %). OB/OW mothers exhibited lower total n-3 PUFAs (P = 0.035), higher ratios of arachidonic acid (C20:4n-6)/eicosapentaenoic acid (C20:5n-3) + docosahexaenoic acid (C22:6n-3), and n-6/n-3 PUFA in colostrum (P = 0.037 and 0.011, respectively), and their offspring had higher body weight and BMI z-scores. Nevertheless, no PUFA composition or n-6/n-3 PUFA ratios in colostrum and 2-month milk were associated with anthropometric parameter changes by age 6 months. Infant birth weight z-scores were independently associated with BMI outcomes at age 6 months (adjusted β = 0.16, 95 % confidence interval (0.05-0.35), P = 0.010) CONCLUSION: Neither n-3 nor n-6 PUFA profiles nor n-6/n-3 PUFA ratios at different lactation stages were found to be associated with anthropometric changes by age 6 months, suggesting that human milk PUFA composition may not be an important determinant of early infant growth trajectories.

High-intensity exercise increases breast milk adiponectin concentrations: a randomised cross-over study

Introduction

Adiponectin plays a role in glucose and fat metabolism and is present in human breast milk. It has been postulated that higher breast milk adiponectin concentrations may prevent rapid weight gain in infancy. Prior research indicates that circulating adiponectin increases acutely after endurance exercise, but no prior research has investigated the effect of exercise on breast milk adiponectin concentrations. The purpose of this randomised, cross-over study was to determine the acute effects of endurance exercise on adiponectin concentrations in human breast milk.

Methods

Participants who were exclusively breastfeeding a 6-12 week-old term infant (N = 20) completed three conditions in the laboratory: (1) Moderate-intensity continuous training (MICT), (2) High-intensity interval training (HIIT), and (3) No activity (REST). At each condition, we collected breast milk at 07:00 h (before exercise/rest), 11:00 h (immediately after exercise/rest), 12:00 h (1 h after exercise/rest), and 15:00 h (4 h after exercise/rest) and determined adiponectin concentrations using enzyme-linked immunosorbent assay. We compared changes in adiponectin concentrations after MICT and HIIT, adjusted for the morning concentration on each test day, with those after REST, using paired t-tests.

Results

Adiponectin concentrations increased 1 h after HIIT, from 4.6 (± 2.2) μg/L in the 07:00 h sample to 5.6 (± 2.6) μg/L. This change was 0.9 μg/L (95% confidence interval 0.3 to 1.5) greater than the change between these two timepoints in the REST condition (p = 0.025). There were no other statistically significant changes in adiponectin concentrations.

Conclusion

HIIT may increase adiponectin concentrations in breast milk acutely after exercise. Further studies should determine the impact of exercise-induced elevations in breast milk adiponectin concentrations on growth and metabolism in infancy.

Understanding the Immunological Quality of Breast Milk in Maternal Overweight and Obesity

Maternal obesity, affecting many pregnant women globally, not only poses immediate health risks but also modulates breast milk composition. Obesity is linked to inflammation and oxidative stress, impacting breast milk's immune properties. This paper explores the intricate relationship between maternal metabolic disorders, such as obesity, and breast milk's immunological components. We conducted a thorough search for original and review articles published until 17 October 2023 in the PUBMED/Scopus database. This search included several terms related to human breast milk, immunological properties, and obesity. Articles were selected with the consensus of all authors. Maternal metabolic disorders have discernible effects on the composition of immune-related components in breast milk, such as immunoglobulins, lactoferrin, leptin, ghrelin, adiponectin, C-reactive protein, growth factors, extracellular vesicles, and lymphocytes. These changes in breast milk composition can significantly impact the newborn's immune system, with potential long-term health implications beyond the immediate postnatal period. Maternal metabolic health is a critical factor in shaping the health trajectory of the neonate through breastfeeding, although the full advantages of breastfeeding for children of mothers with obesity remain uncertain. Ongoing research aims to understand and unravel these links.

Human Milk Nutrient Composition Data is Critically Lacking in the United States and Canada: Results from a Systematic Scoping Review of 2017-2022

Characterization of the nutrients in human milk is important to understand the dietary and developmental requirements of infants. The objective of this review was to summarize the state-of-the-science on the nutrient composition of human milk in the United States and Canada published from 2017 to 2022. Four databases were searched for randomized controlled studies and others given the scoping nature of this review. We limited type to mature milk collected 21 d postpartum and beyond from lactating individuals in the United States and Canada who gave birth at 37-wk gestation or later (full-term). Outcomes of interest included traditional macro- and micronutrients, including human milk oligosaccharides (HMOs), and milk volume. The publication date range was selected as January 1, 2017, to the day the literature search was performed. A total of 32 articles were included in the scoping review from primarily longitudinal cohort or cross-sectional designs. The most prevalent sample collection method was full-breast expression (n = 20) with most studies (n = 26) collecting samples from a single timepoint. Carbohydrates (HMOs [n = 12], glucose [n = 8], and lactose [n = 6]) and protein (n = 5) were the most frequently assessed nutrients in this body of work, with consensus among studies that glucose is present in limited concentrations compared to lactose (24-64 mg/dL compared with 6-7 g/dL) and that HMOs are influenced by temporality and secretor status. Included studies displayed an overall level of heterogeneity and sparsity paralleling previous reports and nutrient data in the USDA FoodData Central system. Much of the data extracted from retained articles generally provided analysis of a specific nutrient or group of nutrients. Moreover, many studies did not use the preferred analytical methods as outlined by the Human Milk Composition Initiative to increase measurement confidence. Up-to-date nutrient composition data of human milk is still greatly needed as it is paramount for the management of infant feeding, assessment of infant and maternal nutritional and health needs, and as a reference for infant formula development.

Associations between Maternal Diet, Human Milk Macronutrients, and Breast-Fed Infant Growth during the First Month of Life in the SMILE Iwamizawa in Japan

Maternal diet may affect human milk macronutrients, but it remains to be elucidated whether this is also influential in infant growth. This study aimed to examine (1) how maternal diet influences human milk macronutrients, and (2) to what extent the variation in milk macronutrients affects infant growth during the first month of life. In 71 Japanese lactating women, maternal dietary information was collected from the brief-type self-administered diet history questionnaire, and anthropometry of mother-infant dyads was collected from medical records. Macronutrients in milk were analyzed by a Human Milk Analyzer. Maternal retinol intake was associated with the carbohydrate content in human milk at 1-month postpartum (standardized β coefficient: 0.287; p = 0.038). Moreover, the energy content in human milk was associated with an increase in the weight standard deviation score based on the WHO growth standard at 1 month of age (standardized β coefficient: 0.399; p = 0.046). Nevertheless, the milk macronutrient was not associated with the risk of infant growth abnormalities. In conclusion, a part of the maternal diet impacts macronutrient contents in human milk, but milk macronutrients have a limited effect on infant growth only within the normal growth curve during the first month of life.

Neonatal intake of Omega-3 fatty acids enhances lipid oxidation in adipocyte precursors

Establishing metabolic programming begins during fetal and postnatal development, and early-life lipid exposures play a critical role during neonatal adipogenesis. We define how neonatal consumption of a low omega-6 to -3 fatty acid ratio (n6/n3 FA ratio) establishes FA oxidation in adipocyte precursor cells (APCs) before they become adipocytes. In vivo, APCs isolated from mouse pups exposed to the low n6/n3 FA ratio had superior FA oxidation capacity, elevated beige adipocyte mRNAs Ppargc1α, Ucp2, and Runx1, and increased nuclear receptor NR2F2 protein. In vitro, APC treatment with NR2F2 ligand-induced beige adipocyte mRNAs and increased mitochondrial potential but not mass. Single-cell RNA-sequencing analysis revealed low n6/n3 FA ratio yielded more mitochondrial-high APCs and linked APC NR2F2 levels with beige adipocyte signatures and FA oxidation. Establishing beige adipogenesis is of clinical relevance, because fat depots with energetically active, smaller, and more numerous adipocytes improve metabolism and delay metabolic dysfunction.

Associations between maternal adiposity and appetite-regulating hormones in human milk are mediated through maternal circulating concentrations and might affect infant outcomes

Background

Appetite-regulating hormones (ARH) in human milk (HM) are suggested to affect infants’ milk intake and possibly infant growth. Maternal adiposity might contribute to higher levels of ARH in HM, either from the mammary gland or from raised circulating levels due to higher adiposity. Counterfactual-based mediation analysis can define indirect and direct effects between HM ARH and maternal and infant factors, and might be an important tool when investigating the mother-milk-infant triad.

Objective

We aim to investigate whether potential associations between (1) maternal adiposity and HM ARH and (2) HM ARH and infant milk intake and growth are mediated through maternal and infant plasma ARH, respectively.

Materials and methods

Maternal and infant anthropometry and body composition, HM and blood samples were collected from 223 mother-infant dyads participating in the Mother, Infant and Lactation Quality study at three postpartum visits from 1 to 8.49 months. Leptin, insulin and adiponectin were analyzed using immunoassays. Mediation analyses using linear mixed-effect models were applied to investigate the direct and indirect effects through maternal and infant plasma hormone concentrations.

Results

A positive association between maternal body-mass-index (BMI) and HM leptin was mediated by maternal plasma leptin by 29% when fixing BMI to < 25 kg/m², and through 51% when fixing BMI to ≥ 25 kg/m² (p_interaction < 0.01). There was no mediated effect through plasma insulin in the association between BMI and HM insulin (p = 0.068). We found negative and positive associations between HM insulin and total milk intake and infant weight, respectively, however, these diminished in mediation analyses with reduced sample sizes.

Conclusion

Our main results suggest that the association between maternal adiposity and HM leptin was mediated through circulating leptin to a stronger degree for mothers with overweight compared to mothers with normal-weight. This indicates that excess maternal adiposity, and the resulting rise of circulating leptin and possible concomitant low-grade inflammation, may be reflected in HM composition.

Clinical trials registry number

NCT03254329.

Infant Red Blood Cell Arachidonic to Docosahexaenoic Acid Ratio Inversely Associates with Fat-Free Mass Independent of Breastfeeding Exclusivity

The prevalence of childhood obesity has increased nearly ten times over the last 40 years, influenced by early life nutrients that have persistent effects on life-long metabolism. During the first six months, infants undergo accelerated adipose accumulation, but little is known regarding infant fatty acid status and its relationship to infant body composition. We tested the hypothesis that a low arachidonic to docosahexaenoic acid ratio (AA/DHA) in infant red blood cells (RBCs), a long-term indicator of fatty acid intake, would associate with more infant fat-free mass (FFM) and/or less adipose accumulation over the first 4 months of life. The fatty acid and composition of breastmilk and infant RBCs, as well as the phospholipid composition of infant RBCs, were quantified using targeted and unbiased lipid mass spectrometry from infants predominantly breastfed or predominantly formula-fed. Regardless of feeding type, FFM accumulation was inversely associated with the infant’s RBC AA/DHA ratio (p = 0.029, R2 = 0.216). Infants in the lowest AA/DHA ratio tertile had significantly greater FFM when controlling for infant sex, adiposity at 2 weeks, and feeding type (p < 0.0001). Infant RBC phospholipid analyses revealed greater peroxisome-derived ether lipids in the low AA/DHA group, primarily within the phosphatidylethanolamines. Our findings support a role for a low AA/DHA ratio in promoting FFM accrual and identify peroxisomal activity as a target of DHA in the growing infant. Both FFM abundance and peroxisomal activity may be important determinants of infant metabolism during development.

Early Growth and Cognitive Development in Children Born Preterm: Relevance of Maternal Body Mass Index

OBJECTIVE

Maternal prepregnancy body mass index (BMI) represents a surrogate marker of fetal exposures to the maternal metabolism during pregnancy. Yet, it remains poorly understood whether this marker indicates risk of altered trajectories in postnatal growth and development in children born preterm. This study aimed to determine whether maternal prepregnancy BMI is associated with altered growth and development in children born preterm.

STUDY DESIGN

A retrospective cohort study evaluated prepregnancy BMI as the exposure for childhood outcomes using linear regression and mixed effects models. The 38 children included in this follow-up evaluation originally participated in a prospective, observational cohort study to determine longitudinal levels of lipid species in preterm human milk expressed by women who delivered prior to 32 weeks. Childhood outcomes in this study were anthropometric measures during hospitalization (n = 38), after discharge through 36 months (n = 34) and Bayley-III developmental scores through 18 months corrected age (n = 26).

RESULTS

In 38 children born prior to 32 weeks, higher maternal prepregnancy BMI was independently associated with higher preterm infant growth velocity during hospitalization, but not associated with in-hospital change in length or head circumference and/or postdischarge growth. In univariate linear regression models, higher maternal BMI was associated with lower cognitive scores at 18 months corrected age. This significant association remained in an adjusted model accounting for relevant influences on early childhood development.

CONCLUSION

Increasing maternal prepregnancy BMI may reflect risk of altered growth and cognitive development in children born preterm.

KEY POINTS

· Maternal BMI was associated with early preterm infant weight gain.. · Maternal BMI was not associated with postdischarge growth.. · Increased maternal BMI may be associated with lower cognitive function scores in offspring..

Infant intakes of human milk branched chain amino acids are negatively associated with infant growth and influenced by maternal body mass index

BACKGROUND

Branched-chain amino acids (BCAAs: isoleucine, leucine, and valine) and aromatic amino acids (AAAs: phenylalanine and tyrosine) are hypothesized to influence early-life obesity risk.

OBJECTIVE

To assess HM free amino acid (AA) concentrations and infant intakes of HM AAs from women with obesity (OB) compared to those with normal weight (NW) and determine the relationships between HM AA consumption and infant growth.

METHODS

HM samples were collected at 0.5 (n = 151), 2 (n = 129), and 6 (n = 93) months postpartum from mothers with NW (body mass index [BMI] = 18.5-24.9 kg/m² ) and OB (BMI > 30 kg/m² ). HM AAs were quantified via mass spectrometry. Infant HM intake, anthropometrics and body composition were assessed. Linear mixed-effects models (LMEM) examined the relationships between maternal BMI and HM AA intakes, and HM AA intake and infant growth over the first 6 months postpartum after adjusting for maternal and infant characteristics.

RESULTS

Maternal BMI was positively associated with infant intakes of isoleucine, leucine, and AAAs across timepoints. HM AA intakes were positively associated with weight-for-length z-score, fat mass index, and fat-free mass index in infants (p < 0.05).

CONCLUSIONS

Maternal BMI led to differences in HM AA composition, which was associated with infant body composition.

Human milk imparts higher insulin concentration in infants born to women with type 2 diabetes mellitus

OBJECTIVE

Human milk (HM) insulin plays many roles for the infant, especially for the newborn. We hypothesized HM insulin in women with type 2 diabetes (T2DM) would be higher than BMI-matched women with either gestational diabetes (GDM) or normal glucose tolerance (NGT). In T2DM, we also assessed macronutrient composition and relationships between maternal glycemic control and HM insulin.

STUDY DESIGN

HM was characterized at 2-weeks postpartum among three BMI-matched groups: T2DM (n= 12), diet-controlled GDM (n= 12), and NGT (n= 12). In T2DM, additional fasting and postprandial HM samples were collected while wearing a continuous glucose monitor (CGM), as well as fasting and 90-minute postprandial samples after a standardized meal at 1-2 weeks postpartum.

RESULTS

Fasting HM insulin was two times higher in T2DM compared to GDM and NGT (p < .001), which were not different from each other. Among T2DM, fasting (p < .001) and postprandial (p = .01) HM insulin levels were between 2 and 5× higher than plasma. Postprandial HM insulin (p = .03) and glucose (p < .001) were increased compared to fasting. Mean nocturnal glucose (p < .01) and maternal hemoglobin A1c (p < .01) positively associated with fasting HM insulin.

CONCLUSIONS

These data are the first to show HM insulin concentrations are doubled in T2DM compared to BMI-matched GDM and NGT. In HM of T2DM, insulin increases postprandially, may be concentrated relative to plasma, and is influenced by maternal glycemic control, with potential clinical implications that merit further study.

Metabolic Conditions Including Obesity, Diabetes, and Polycystic Ovary Syndrome: Implications for Breastfeeding and Breastmilk Composition

Breastfeeding is internationally recognized as the recommended standard for infant nutrition, informed by evidence of its multiple benefits for both mother and baby. In the context of common metabolic conditions such as polycystic ovary syndrome, diabetes (type 1, type 2, and gestational), and obesity, breastfeeding may be particularly beneficial for both mother and infant. However, there is evidence of delayed lactogenesis and reduced breastfeeding rates and duration in women with these conditions, and the effects of altered maternal metabolic environments on breastmilk composition (and potentially infant outcomes) are incompletely understood. In this review, we explore the relationships between maternal metabolic conditions, lactogenesis, breastfeeding, and breastmilk composition. We examine relevant potential mechanisms, including the central role of insulin both in lactogenesis and as a milk-borne hormone. We also describe the bioactive and hormonal components of breastmilk and how these may link maternal and infant health.

Human Milk Metabolic Hormones: Analytical Methods and Current Understanding

Human milk (HM) contains a wide array of peptide hormones including leptin and adiponectin, which are involved in the regulation of infant growth and development. These essential hormones might play an important role in the regulation of metabolic reprogramming of the new-born infant. However, HM hormone studies are sparse and heterogeneous in regard to the study design, sample collection, preparation and analysis methods. This review discussed the limitations of HM hormone analysis highlighting the gaps in pre-analytical and analytical stages. The methods used to quantify HM metabolic hormones (leptin, adiponectin, ghrelin, insulin, obestatin, resistin and apelin) can be classified as immunoassay, immunosensor and chromatography. Immunoassay methods (ELISA and RIA) have been predominantly used in the measurement of these HM hormones. The relative validity parameters of HM hormones analysis are often overlooked in publications, despite the complexity and differences of HM matrix when compared to that of plasma and urine. Therefore, appropriate reports of validation parameters of methodology and instrumentation are crucial for accurate measurements and therefore better understanding of the HM metabolic hormones and their influences on infant outcomes.

Human Breast Milk: Bioactive Components, from Stem Cells to Health Outcomes

PURPOSE OF REVIEW

Breast milk (BM) is a peculiar fluid owing unique properties and resulting the ideal food during early neonatal period. As widely known, it can improve the outcome of both neonate and lactating mother, influencing their whole life. BM is characterized by several beneficial components; among these, a great role is played by BM own and specific microbiome, deeply investigated in many studies. Moreover, the use of metabolomics in BM analysis allowed a better characterization of its metabolic pathways that vary according to lactation stage and neonatal gestational age. The aim of this review is to describe growth factors, cytokines, immunity mediators, and stem cells (SCs) contained in BM and investigate their functions and effects on neonatal outcome, especially focusing on immuno- and neurodevelopment.

RECENT FINDINGS

We evaluated recent and updated literature on this field. The article that we analyzed to write this review have been found in MEDLINE using breast milk-derived stem cells, biofactors, growth factors, breastfeeding-related outcomes, neurodevelopment, and neonatal immunological system as keywords. Discovering and characterizing BM components could result very useful to clarify the pathophysiology of their influence on neonatal growth and even to improve artificial formulations' composition. Moreover, since SCs abilities and their involvement in the development of several diseases, they could help to discover specific targets for new therapies. It could be useful to characterize BM-derived SC markers, properties, and variations during lactation stages, to understand their potential role in therapeutic applications, since they could be noninvasively isolated from BM. More studies will help to describe more in detail the characteristics of mother-to-child communication through breastfeeding and its potential role in the next future.

Protein Profile and Simulated Digestive Behavior of Breast Milk from Overweight and Normal Weight Mothers

Human milk proteins have shown to vary in concentration and distribution through lactation. However, while some regulatory components, such as hormones, have shown associations with regard to the mothers' body mass index, there is limited information on the possible influence of this condition on the whole protein distribution. The objective of this study was to evaluate the protein profile of human milk from normal weight and overweight or obese mothers to identify differences in protein expression in colostrum, transitional and mature milk. The mass spectrometry analysis showed the ability to class with a high degree of confidence the lactation state and the milk profile according to the mother's condition. Individual milk samples were subjected to a digestion in vitro model that takes into account the specificities of the gastrointestinal conditions of full-term newborn infants. The digestion products were compared with available data from the digestive contents in newborns. The behavior of the most abundant proteins and the overall peptide generation and survival, showed good correspondence with in vivo data.

Polyunsaturated fatty acids as modulators of fat mass and lean mass in human body composition regulation and cardiometabolic health

It is now recognized that the amount and type of dietary fat consumed play an important role in metabolic health. In humans, high intake of polyunsaturated fatty acids (PUFAs) has been associated with reductions in cardiovascular disease risk, improvements in glucose homeostasis, and changes in body composition that involve reductions in central adiposity and, more recently, increases in lean body mass. There is also emerging evidence, which suggests that high intakes of the plant-based essential fatty acids (ePUFAs)-n-6 linoleic acid (LA) and n-3 α-linolenic acid (ALA)-have a greater impact on body composition (fat mass and lean mass) and on glucose homeostasis than the marine-derived long-chain n-3 PUFA-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In addition, high intake of both ePUFAs (LA and ALA) may also have anti-inflammatory effects in humans. The purpose of this review is to highlight the emerging evidence, from both epidemiological prospective studies and clinical intervention trials, of a role for PUFA, in particular ePUFA, in the long-term regulation of body weight and body composition, and their impact on cardiometabolic health. It also discusses current notions about the mechanisms by which PUFAs modulate fat mass and lean mass through altered control of energy intake, thermogenesis, or lean-fat partitioning.

Growth patterns and breast milk/infant formula energetic efficiency in healthy infants up to 18 months of life: the COGNIS study

Type of feeding during early life influences growth trajectory and metabolic risk at later ages. Modifications in infant formula composition have led to evaluate their effects on growth and energetic efficiency (EE) compared with breast-feeding. Main goal was to analyse type of feeding potential effects during first months of life, plus its EE, on growth patterns in healthy formula fed (standard infant formula (SF) vs. experimental infant formula enriched with bioactive nutrients (EF)) and breastfed (BF) infants participating in the COGNIS RCT (http://www.ClinicalTrials.gov, Identifier: NCT02094547) up to 18 months of age. Infants follow-up to 18 months of age (n 141) fed with a SF (n 48), EF(n 56), or BF (n 37), were assessed for growth parameters using WHO standards. Growth velocity (GV) and catch-up were calculated to identify growth patterns. EE of breast milk/infant formula was also estimated. Infants' growth at 6 months showed higher length and lower head circumference gains in SF and EF infants than BF infants. Both weight-for-length and weight-for-age catch-up growth showed significant differences in formula fed groups compared with the BF. No significant differences in GV or catch-up were found at 6-12 and 12-18 months. Regarding EE, infant formula groups showed significantly lower weight and length gains/g of milk protein, and higher weight and length gains/g of milk lipids, than the BF infants. GV during first 6 months, which may be influenced by feeding, seems to be the main predictor of subsequent growth trajectory. Breast-feeding may have positive effects on growth programming due to its nutrients' EE.

Longitudinal human milk macronutrients, body composition and infant appetite during early life

BACKGROUND & AIMS

Breastfeeding is the gold standard infant feeding. Data on macronutrients in relation to longitudinal body composition and appetite are very scarce. The aim of this study was to investigate longitudinal human milk macronutrients at 1 and 3 months in association with body composition and appetite during early life in healthy, term-born infants. We hypothesized that infants receiving higher caloric human milk would have more body fat mass and satiate earlier.

METHODS

In 133 exclusively breastfed infants (Sophia Pluto Cohort), human milk samples at 1 and 3 months were analyzed for macronutrients (fat, protein, carbohydrate) by MIRIS Human Milk Analyzer, with appetite assessment by Baby Eating Behavior Questionnaires. Fat mass (FM) and fat-free mass (FFM) were measured by PEA POD and DXA, and abdominal FM by ultrasound.

RESULTS

Milk samples showed large differences in macronutrients, particularly in fat content. Protein and energy content decreased significantly from 1 to 3 months. Fat and carbohydrate content tended to decrease (p = 0.066 and 0.081). Fat (g/100 ml) and energy (kcal/100 ml) content at 3 months were associated with FM% at 6 months (β 0.387 and 0.040, resp.) and gain in FM% from 1 to 6 months (β 0.088 and 0.009, resp.), but not with FM% at 2 years. Carbohydrate content at 3 months tended to associate with visceral FM at 2 years (β 0.290, p = 0.06). Infants receiving higher caloric milk were earlier satiated and finished feeding faster.

CONCLUSIONS

Our longitudinal data show decreasing milk protein and energy content from age 1 to 3 months, while fat and carbohydrate tended to decrease. Macronutrient composition, particularly fat content, differed considerably between mothers. Milk fat and energy content at 3 months associated with gain in FM% from age 1 to 6 months, indicating that higher fat and energy content associate with higher gain in FM% during the critical window for adiposity programming. As infants receiving higher caloric breastfeeding were earlier satiated, this self-regulatory mechanism might prevent intake of excessive macronutrients.

ONLINE TRIAL REGISTRY

NTR, NL7833.

Milk Bank Pooling Practices Impact Concentrations and Variability of Bioactive Components of Donor Human Milk

Background: Donor human milk (DHM) bank practices, such as pasteurization and pooling according to postpartum age of milk donations and number of donors included in a pool may impact the resulting concentration of bioactive components of DHM. Aims: We determined the impact of Holder pasteurization, postpartum milk age, and pool donor number (number of donors included in a pool) on resulting concentrations of total immunoglobulin A (IgA; which provides immune protection to the recipient infant) and insulin (an important hormone for gut maturation).We also documented inter-relationships between these bioactive components and macronutrients in DHM pools. Methods: Pre and post-pasteurization aliquots of 128 DHM samples were obtained from the Rocky Mountain Children's Foundation Mother's Milk Bank (a member of the Human Milk Banking Association of North America, HMBANA). Macronutrients were measured via mid-infrared spectroscopy. Total IgA was measured via customized immunoassay in skim milk and insulin was measured via chemiluminescent immunoassay. Results: Mean post-pasteurization total IgA concentration was 0.23 ± 0.10 (range: 0.04-0.65) mg/mL a 17.9% decrease due to pasteurization (n = 126). Mean post-pasteurization DHM insulin concentration was 7.0 ± 4.6 (range: 3-40) μU/mL, a decrease of 13.6% due to pasteurization (n = 128). The average DHM pool postpartum milk age was not associated with total IgA or insulin concentrations, but pool donor number was associated with bioactive components. Pools with only one donor had lower total IgA and lower insulin concentrations than pools with at least 2 donors (p < 0.05). Increasing the number of donors in a pool decreased the variability in total IgA and insulin concentrations (p < 0.04). Conclusion: Increasing the number of donors included in DHM pools may help optimize bioactive components in DHM received by premature infants. These results help inform milk banking practices to decrease compositional variability in produced DHM pools.

Human milk composition differs by maternal BMI in the first 9 months postpartum

BACKGROUND

Studies indicate that maternal weight status modulates human milk composition; however, results are conflicting.

OBJECTIVES

Our objective was to examine the relation between maternal body composition and human milk macronutrients and bioactive components and also their association with infant daily intakes and body composition.

METHODS

Human milk samples were obtained from a longitudinal study (NCT01131117) in normal weight (NW: 18.5-24.9 kg/m2, n = 88) and overweight/obese (OW: 25-35 kg/m2, n = 86) women between 0.5 and 9 mo postpartum. Macronutrient content was estimated using mid-infrared spectroscopy. Leptin, insulin, and C-reactive protein (CRP) were measured using electrochemiluminescence immunoassays. Infant body composition was obtained using quantitative MRI. Linear mixed models were adjusted for postpartum age and infant sex.

RESULTS

Human milk in OW mothers was higher in fat and protein and lower in carbohydrate content at some time points compared with that in NW mothers. Human milk leptin, insulin, and CRP concentrations were higher in OW mothers compared with NW mothers, with infants of OW mothers exposed to 1.5-2.5 times higher concentrations of leptin and insulin compared with infants of NW mothers. Similar results were observed when concentrations were normalized to infant daily intake and body weight. The effect sizes of infant daily intakes associated with infant growth parameters were small for macronutrients [0.005-0.05 z-score units and 0.02-0.45 fat mass index (FMI) or fat-free mass index units per unit of change in composition, P < 0.05]. Larger effect sizes were seen with human milk insulin and leptin (0.24 z-score units and 0.37-1.15 FMI units per unit of change in composition, P < 0.05).

CONCLUSIONS

These findings demonstrate that infants of OW mothers are exposed to higher concentrations of insulin, leptin, and, to a lesser extent, CRP. The bioavailability of these 3 human milk bioactives and their mechanisms of action in the infant are unclear.This trial was registered at clinicaltrials.gov as NCT01131117.

Type 2 Diabetes in Youth: the Role of Early Life Exposures

PURPOSE OF REVIEW

This review examines the impact of early life exposures on glucose metabolism in the offspring and explores potential metabolic mechanisms leading to type 2 diabetes in childhood.

RECENT FINDINGS

One in five adolescents is diagnosed with prediabetes. Recent studies have elucidated the impact of early exposures such as maternal diabetes, but also hyperglycemia below the threshold of gestational diabetes, obesity, hyperlipidemia, and paternal obesity on the future metabolic health of the offspring. Mechanisms affecting the developmental programing of offspring toward type 2 diabetes include epigenetic modifications, alterations in stem cell differentiation, metabolome and microbiome variation, immune dysregulation, and neonatal nutrition. The risk of type 2 diabetes in offspring is increased not only by diabetes exposure in utero but also by exposure to a heterogeneous milieu of factors that accompany maternal obesity that provoke a vicious cycle of metabolic disease. The key period for intervention to prevent type 2 diabetes is within the first 1000 days of life.

Growth Factor Concentrations in Human Milk Are Associated With Infant Weight and BMI From Birth to 5 Years

Background: Human milk bioactives may play a role in infant health and development. Although the variability in their concentrations in milk is well-established, the impact of differential milk profiles on infant growth outcomes remains unclear. Thus, the aim of the present study was to investigate whether different concentrations of metabolic hormones are associated with different weight and BMI in infants beyond the first year of life. Methods: Milk samples at 2.6 (±0.4) months after birth and anthropometric measures at 13 months, 2, 3, and 5 years were collected as part of the Finnish STEPS cohort study from 501 mothers and the respective 507 infants. Leptin, adiponectin, insulin-like growth factor (IGF)-1 and cyclic glycine-proline (cGP) in milk were analyzed. Multiple regression models and a repeated measures mixed model were used to examine associations between milk hormone concentrations and weight and BMI z-scores across time, at each time-point, and weight gain from birth to each follow-up visit. All models were corrected for birth weight, infant sex, duration of exclusive and total breastfeeding, time of introduction of solid foods and maternal pre-pregnancy BMI. Results: Higher milk IGF-1 was associated with higher weight at 13 months (p = 0.004) but lower weight at 3 (p = 0.011) and 5 years of age (p = 0.049). Higher cGP was associated with lower weight across the 5 years (p = 0.019) but with higher BMI at 5 years (p = 0.021). Leptin and adiponectin did not display associations with infant growth at this time. Sex interactions were also absent. Conclusions: Our results suggest that the interplay between human milk-borne IGF-1 and cGP is similar to that reported in other mammals and may have an important role in defining infant growth trajectories beyond the first year of life. Further research should explore the determinants and origins of these milk-borne compounds and evaluate their effect on infant growth and metabolism.

Third-Trimester Glucose Homeostasis in Healthy Women Is Differentially Associated with Human Milk Oligosaccharide Composition at 2 Months Postpartum by Secretor Phenotype

Human milk oligosaccharides (HMOs) are bioactive molecules in human milk that play a critical role in infant health. Obesity and associated metabolic aberrations can negatively impact lactation and alter milk composition. Here, the relationship between maternal glucose homeostasis and HMO composition from 136 healthy women was examined. Maternal glucose homeostasis (fasting plasma glucose and insulin, homeostatic model assessment for insulin resistance, and insulin sensitivity index) was evaluated at 30 weeks of gestation in healthy women (body mass index = 18.5–35 kg/m²). Human milk samples were collected at two months postpartum. HMO concentrations were measured via high performance liquid chromatography. Women were categorized into “secretor” and “non-secretor” groups based on 2′-Fucosyllactose concentrations (<100 nmol/mL, non-secretor). Pearson’s correlation analysis and linear models were used to assess the relationships between maternal glucose homeostasis and HMO concentrations. In non-secretors, third trimester fasting plasma glucose and insulin were negatively associated with total HMO-bound sialic acid and concentrations of the sialylated HMOs 3′-sialyllactose and disialylacto-N-tetraose. In secretors, difucosyllactose and lacto-N-fucopentaose-II concentrations increased and sialyllacto-N-tetraose c and sialyllacto-N-tetraose b decreased as insulin sensitivity increased. This study is the first to demonstrate a relationship between obesity-associated maternal factors and HMO composition in both secretor and non-secretor populations.

Maternal gestational diabetes and infant feeding, nutrition and growth: a systematic review and meta-analysis

Gestational diabetes mellitus (GDM) is a major health problem, with increased risks of obesity and diabetes in offspring. However, little is known about the effect of GDM on infant feeding, nutrition and growth, and whether these factors play a role in mediating these risks. We systematically reviewed evidence for the effect of GDM on infant feeding, nutrition and growth. We searched MEDLINE, Web-of-Science, Embase, CINAHL and CENTRAL for studies that reported outcomes in infants <2 years who were and were not exposed to GDM. Studies of pre-gestational diabetes were excluded. Meta-analysis was performed for three epochs (1–6, 7–12, 13–24 months), using inverse-variance, fixed-effects methods. Primary outcomes were energy intake (kJ) and BMI (kg/m2). Twenty-five studies and 308 455 infants were included. Infants exposed to GDM, compared with those not exposed, had similar BMI at age 1–6 months (standardised mean difference (SMD) = 0·01, 95 % CI −0·04, 0·06; P = 0·69) and 7–12 months (SMD = 0·04, 95 % CI −0·01, 0·10; P = 0·09), reduced length at 1–6 and 7–12 months, increased whole-body fat at 1–6 months, higher rates of formula supplementation in hospital, shorter duration of breast-feeding and decreased rates of continued breast-feeding at 12 months. Breast milk of women with GDM had lower protein content. There was no association between GDM and infant weight and skinfold thickness. No data were available for nutritional intake and outcomes at 13–24 months. Low- or very low-quality evidence suggests GDM is not associated with altered BMI in infancy, but is associated with increased fat mass, high rates of formula use and decreased duration of breast-feeding.

Sexually Dimorphic Associations between Maternal Factors and Human Milk Hormonal Concentrations

While human milk composition is characterised by marked dynamicity, we are far from having a clear picture of what factors drive this variation. Hormones in human milk are known to vary according to specific maternal phenotypes, but limited evidence shows the infant also has a role in determining milk composition. The present study aimed to investigate the interplay between maternal and infant characteristics in relation to human milk hormonal profile. In total, 501 human milk samples from mothers recruited in the Finnish STEPS cohort study (Steps to the healthy development) were analysed. Pre-pregnancy and pregnancy maternal data, socioeconomic status and infant characteristics at birth were collated. Leptin, adiponectin, insulin-like growth factor-1 and cyclic Glycine-Proline in milk were measured. Multivariate analysis of variance (MANOVA) and linear regression were utilised for statistical analysis. Sex-specific interactions with maternal factors were observed, as the infant sex mediated associations between gestational diabetes and milk adiponectin (p = 0.031), birth-mode and total protein (p = 0.003), maternal education and insulin-like growth factor-1: cyclic Glycine-Proline ratio (p = 0.035). Our results suggest that changes in human milk composition are associated with interactions between maternal and infant characteristics and pathophysiological factors. Future work should expand on these findings and further explore the link between hormonal profiles in human milk and infant outcomes.

Epigenetics: Linking Early Postnatal Nutrition to Obesity Programming?

Despite constant research and public policy efforts, the obesity epidemic continues to be a major public health threat, and new approaches are urgently needed. It has been shown that nutrient imbalance in early life, from conception to infancy, influences later obesity risk, suggesting that obesity could result from "developmental programming". In this review, we evaluate the possibility that early postnatal nutrition programs obesity risk via epigenetic mechanisms, especially DNA methylation, focusing on four main topics: (1) the dynamics of epigenetic processes in key metabolic organs during the early postnatal period; (2) the epigenetic effects of alterations in early postnatal nutrition in animal models or breastfeeding in humans; (3) current limitations and remaining outstanding questions in the field of epigenetic programming; (4) candidate pathways by which early postnatal nutrition could epigenetically program adult body weight set point. A particular focus will be given to the potential roles of breast milk fatty acids, neonatal metabolic and hormonal milieu, and gut microbiota. Understanding the mechanisms by which early postnatal nutrition can promote lifelong metabolic modifications is essential to design adequate recommendations and interventions to "de-program" the obesity epidemic.

Hormones in Breast Milk and Effect on Infants' Growth: A Systematic Review

Breast milk is characterized by a dynamic and complex composition which includes hormones and other bioactive components that could influence infant growth, development, and optimize health. Among the several beneficial effects associated with prolonged breastfeeding, a 13% decrease in the risk of overweight and obesity has been reported. Recent research has focused on breast milk hormones contributing to the appetite and energy balance regulation and adiposity. Accordingly, we conducted a literature systematic review with the aim to provide an update on the effect of leptin, ghrelin, Insulin Growth Factor 1, adiponectin, and insulin on infants' and children's growth and body composition. The revised literature reveals contrasting findings concerning the potential role of all these hormones on modeling growth and fat mass apposition and health outcomes later in life. Further studies are needed to gain further insight into the specific role of these bioactive components in metabolic pathways related to body composition. This could help gain a further insight on infants' growth, both in physiological and pathological settings.

Maternal pre-pregnancy weight status modifies the influence of PUFAs and inflammatory biomarkers in breastmilk on infant growth

Background

Human breastmilk contains pro- and anti-inflammatory compounds and hormones that can influence infant growth. However, little is known about the specific interrelationships between these compounds and whether their effects on infant growth may be influenced by pre-pregnancy weight status.

Objective

The purpose of this novel, prospective cohort study was to assess the interrelationships between pro-inflammatory cytokines (TNF-α, IL-6), hormones (insulin, leptin) and PUFAs (n-6, n-3) in blood and breastmilk in early postpartum between women with normal BMI (Group 1, n = 18; 18.5<BMI≤24.9 kg/m²) and with overweight/obesity (Group 2, n = 15; BMI≥25.0 kg/m²) before pregnancy to determine if these components correlated to infant growth measures at age 4–8 weeks.

Methods

Participants were robustly phenotyped along with their infants at 4–8 weeks postpartum. TNF-α, IL-6, insulin, leptin, and n-3 and n-6 PUFAs measured in blood and breastmilk and compared between pre-pregnancy BMI groups and with infant weight, length, head circumference and % fat mass.

Results

Group 1 women had higher serum leptin (p<0.01) and breastmilk leptin (p<0.001) compared to Group 2. Other inflammatory markers, hormones, and total n-6, n-3 and n-6/n-3 ratio PUFAs were similar between pre-pregnancy BMI groups. No relationships were observed between whey inflammatory markers, hormones, PUFAs and growth measures in infants born to Group 2 women. However, TNF-α was positively related and, IL-6, leptin, insulin, total n-6, n-3 and n-6/n-3 PUFAs in whey breastmilk were negatively correlated to infant growth measures in infants born to Group 1 women (p<0.01).

Conclusions

Pro-inflammatory qualities of breastmilk were associated with infant growth measures regardless of maternal pre-pregnancy BMI. However, infants born to women with overweight or obesity demonstrated less responsive growth to breastmilk contents. More studies are needed to assess longitudinal effects of this impact.

Distribution of bioactive factors in human milk samples

Background

Breast milk provides nutrition for infants and also contains a variety of bioactive factors that influence the development of the newborn. Human milk is a complex biological fluid that can be separated into different layers (water phase and lipid phase with its component water and lipid fractions). It can affect the developing human body along the whole length of the gastrointestinal tract, and through the circulation, its factors may reach every organ.

Methods

In the present study, we analyzed milk samples collected monthly for 6 months from 16 mothers from the 4^th week postpartum between 2014 and 2016 in Baranya County, Hungary. The 96 samples provided us information about the fluctuation of certain bioactive factors during the first 6 months of lactation. We investigated with Luminex technology the concentrations of several cytokines (CD40, Flt-3L), chemokines (MCP-1, RANTES, GRO, MIP-1ß, MDC, eotaxin, fractalkine), and epidermal growth factor (EGF). Paired t-tests and one-way ANOVA followed by Bonferroni post-hoc tests were used to compare the data.

Results

We detected the presence of each bioactive factor in every layer of the milk samples during the first 6 months of breastfeeding in widespread concentration ranges. In the case of GRO, MIP-1ß, MDC, Flt-3L, fractalkine, and eotaxin, the concentrations were constant during the first 6 months of lactation. The water phase of human milk contained higher factor concentrations compared to both fractions of the lipid phase for most factors (except eotaxin and MIP-1ß). The concentrations of CD40, EGF, MCP-1, and RANTES in the first 3 months were significantly different compared to the values detected between 4^th and 6^th months. In the water phase, the level of MCP-1 was significantly decreased, while all of the other factors increased during the 4^th through 6^th months. We found significantly higher EGF, GRO, and RANTES levels in the water fraction compared to the lipid fraction of the lipid phase.

Conclusions

The novel findings of this investigation were the presence of Flt-3L and MDC in all layers of breast milk, and nearly all bioactive factors in the lipid phase. Due to their widespread physiological effects these factors may have an essential role in organogenesis.

Human Milk Adiponectin and Leptin and Infant Body Composition over the First 12 Months of Lactation

Human milk (HM) adipokines may influence infant feeding patterns, appetite regulation, and body composition (BC). The associations between concentrations/calculated daily intakes (CDI) of HM adipokines in the first 12 months postpartum and maternal/term infant BC, and infant breastfeeding parameters were investigated. BC of breastfeeding dyads (n = 20) was measured at 2, 5, 9, and/or 12 months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). 24-h milk intake and feeding frequency were measured along with whole milk adiponectin and skim and whole milk leptin (SML and WML) and CDI were calculated. Statistical analysis used linear regression/mixed effects models; results were adjusted for multiple comparisons. Adipokine concentrations did not associate with infant BC. Higher CDI of adiponectin were associated with lower infant fat-free mass (FFM; p = 0.005) and FFM index (FFMI; p = 0.009) and higher fat mass (FM; p < 0.001), FM index (FMI; p < 0.001), and %FM (p < 0.001). Higher CDI of SML were associated with higher infant FM (p < 0.001), FMI (p < 0.001), and %FM (p = 0.002). At 12 months, higher CDI of WML were associated with larger increases in infant adiposity (2–12 month: FM, p = 0.0006; %FM, p = 0.0004); higher CDI of SML were associated with a larger decrease in FFMI (5–12 months: p = 0.0004). Intakes of HM adipokines differentially influence development of infant BC in the first year of life, which is a critical window of infant programming and may potentially influence risk of later disease via modulation of BC.