Hormones In Breast Milk Research Articles

ГОРМОНЫ ГРУДНОГО МОЛОКА КАК ФАКТОРЫ РИСКА ИЛИ ПРОТЕКТОРЫ РАЗВИТИЯ ДЕТСКОГО ОЖИРЕНИЯ

The current data on the role of breast milk hormones in the development of obesity in children are summarized. Based on the analysis of domestic and foreign special scientific and practical literature on the databases PubMed, Scopus, Elsevier, eLibrary, information on the genetic basis of the development of obesity is considered. Based on the results of the systematization of the information received, the question was raised about the need for further research in this area due to the relevance of the problems being discussed.

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

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

O061 Maternal Circadian Disruption from Shift Work and the Impact on the timing of Melatonin in their Breast Milk

Abstract Introduction Infants are not born with a circadian rhythm. Research shows that breast milk clearly exhibits a 24-hour pattern, with melatonin concentrations high during the evening and night but barely detectable in daytime milk. The presence and timing of melatonin in breast milk suggests that this hormone may help provide sleep timing information to infants, thereby supporting the development of their own circadian cycle. Currently, it is not known if disturbances of maternal circadian rhythm, such as shift work, impact the circadian rhythmicity of breastmilk. The aim of this study was to investigate whether maternal circadian disruption, from working night shift has an impact on melatonin timing in breastmilk. Methods A prospective repeated measures study design was undertaken to compare melatonin levels in breastmilk across shift types (day shift/non-workdays and night shifts). Four 10ml breastmilk samples were collected by participants the same time of the day, across five consecutive days. Results. A total of 11 mothers completed the study. Analysis is still ongoing but preliminary results show a potential difference in breastmilk melatonin between pre-night shift, night shift and post night shift, indicating a change in the circadian timing of the breastmilk. Discussion The findings from this study suggest that there is a potential effect from maternal circadian disruption from shift work on breast milk melatonin. This is an important first step in exploring the impact of maternal circadian misalignment disorders on breastmilk hormones and provides preliminary evidence that future research is needed in this area.

Exploring Molecular Interactions between Human Milk Hormone Insulin and Bifidobacteria.

Multiple millennia of human evolution have shaped the chemical composition of breast milk toward an optimal human body fluid for nutrition and protection and for shaping the early gut microbiota of newborns. This biological fluid is composed of water, lipids, simple and complex carbohydrates, proteins, immunoglobulins, and hormones. Potential interactions between hormones present in mother's milk and the microbial community of the newborn are a very fascinating yet unexplored topic. In this context, insulin, in addition to being one of the most prevalent hormones in breast milk, is also involved in a metabolic disease that affects many pregnant women, i.e., gestational diabetes mellitus (GDM). Analysis of 3,620 publicly available metagenomic data sets revealed that the bifidobacterial community varies in relation to the different concentrations of this hormone in breast milk of healthy and diabetic mothers. Starting from this assumption, in this study, we explored possible molecular interactions between this hormone and bifidobacterial strains that represent bifidobacterial species commonly occurring in the infant gut using 'omics' approaches. Our findings revealed that insulin modulates the bifidobacterial community by apparently improving the persistence of the Bifidobacterium bifidum taxon in the infant gut environment compared to other typical infant-associated bifidobacterial species. IMPORTANCE Breast milk is a key factor in modulating the infant's intestinal microbiota composition. Even though the interaction between human milk sugars and bifidobacteria has been extensively studied, there are other bioactive compounds in human milk that may influence the gut microbiota, such as hormones. In this article, the molecular interaction of the human milk hormone insulin and the bifidobacterial communities colonizing the human gut in the early stages of life has been explored. This molecular cross talk was assessed using an in vitro gut microbiota model and then analyzed by various omics approaches, allowing the identification of genes associated with bacterial cell adaptation/colonization in the human intestine. Our findings provide insights into the manner by which assembly of the early gut microbiota may be regulated by host factors such as hormones carried by human milk.

Association of maternal body composition and diet on breast milk hormones and neonatal growth during the first month of lactation.

Preterm birth is associated with altered growth patterns and an increased risk of cardiometabolic diseases, with breast milk (BM) being a counteracting factor. Preterm infants also show alterations in adipokines and gut hormones influencing appetite and metabolism. Since these hormones are present in BM, it is possible that their levels may equilibrate deficiencies improving infant growth. We aimed to assess 1) the BM levels of ghrelin, resistin, leptin, insulin, peptide YY, and the gastrointestinal peptide in women with preterm and term labor; 2) the relationship between BM hormones and neonatal growth; and 3) the influence of maternal body composition and diet on these BM hormones. BM from 48 women (30 term and 18 preterm labor) was collected at days 7, 14, and 28 of lactation. Maternal body composition was evaluated by bioimpedance, and neonate anthropometric parameters were collected from medical records. The maternal dietary pattern was assessed by a 72-h dietary recall at days 7 and 28 of lactation. BM hormones were analyzed by the U-Plex Ultra-sensitive method. Data were analyzed using linear regression models. BM from women with preterm labor had lower ghrelin levels, with the other hormones being significantly higher compared to women with term delivery. In premature infants, growth was positively associated with BM ghrelin, while, in term infants, it was positively associated with insulin and negatively with peptide YY. In the first week of lactation, women with preterm labor had higher body fat compared to women with term labor. In this group, ghrelin levels were positively associated with maternal body fat and with fiber and protein intake. In women with term labor, no associations between anthropometric parameters and BM hormones were found, and fiber intake was negatively associated with peptide YY. Preterm labor is a factor influencing the levels of BM adipokines and gut hormones, with BM ghrelin being a relevant hormone for premature infant growth. Since ghrelin is lower in BM from women with preterm labor and the levels are associated with maternal fat storage and some dietary components, our data support the importance to monitor diet and body composition in women who gave birth prematurely to improve the BM hormonal status.

Состав грудного молока при ожирении матери: влияние на развитие ребенка

This review analyzes changes in the composition of breast milk observed in obese women compared to those with normal weight. The maternal diet primarily affects the level of fat and leptin in breastmilk. It is the level of leptin in breastmilk that differs significantly between obese and non-obese women within the first month after childbirth. The psychological status of the mother was shown to affect the composition of macronutrients, immune components, and hormones in breastmilk. Breastfeeding is critical for the development of an infant's gut microbiota and maturation of its immune system. The analysis of breastmilk composition has a practical value, because it helps to develop infant formulas the composition of which is close to breastmilk. Key words: maternal obesity, breastmilk, gut microbiota, composition, vitamin D metabolism, genetic polymorphism

Breast milk apelin level increases with maternal obesity and high-fat feeding during lactation.

Recent evidence indicates that levels of breast milk (BM) hormones such as leptin can fluctuate with maternal adiposity, suggesting that BM hormones may signal maternal metabolic and nutritional environments to offspring during postnatal development. The hormone apelin is highly abundant in BM but its regulation during lactation is completely unknown. Here, we evaluated whether maternal obesity and overnutrition impacted BM apelin and leptin levels in clinical cohorts and lactating rats. BM and plasma samples were collected from normal-weight and obese breastfeeding women, and from lactating rats fed a control or a high fat (HF) diet during lactation. Apelin and leptin levels were assayed by ELISA. Mammary gland (MG) apelin expression and its cellular localization in lactating rats was measured by quantitative RT-PCR and immunofluorescence, respectively. BM apelin levels increased with maternal BMI, whereas plasma apelin levels decreased. BM apelin was also positively correlated with maternal insulin and C-peptide levels. In rats, maternal HF feeding exclusively during lactation was sufficient to increase BM apelin levels and decrease its plasma concentration without changing body weight. In contrast, BM leptin levels increased with maternal BMI in humans, but did not change with maternal HF feeding during lactation in rats. Apelin is highly expressed in the rat MG during lactation and was mainly localized to mammary myoepithelial cells. We found that MG apelin gene expression was up-regulated by maternal HF diet and positively correlated with BM apelin content and maternal insulinemia. Our study indicates that BM apelin levels increase with long- and short-term overnutrition, possibly via maternal hyperinsulinemia and transcriptional upregulation of MG apelin expression in myoepithelial cells. Apelin regulates many physiological processes, including energy metabolism, digestive function, and development. Further studies are needed to unravel the consequences of such changes in offspring development.

Is breast milk iodine concentration an influential factor in growth- and obesity-related hormones and infants' growth parameters?

Iodine, a key constituent of thyroid hormones, plays an indirect role in prenatal and postnatal growth. This study aimed to investigate whether breast milk iodine concentration (BMIC) is associated with growth‐ and obesity‐related hormones and subsequently the infants' anthropometric measures. In present study conducted in Tehran (Iran), 94 lactating mothers and healthy infants who were exclusively breastfed were included. Concentrations of iodine, insulin‐like growth factor‐1 (IGF‐1), adiponectin (AD) and leptin (LP) were measured in breast milk samples collected during 3‐ to 5‐day postpartum. Anthropometric measures of infants were assessed at 6 months of life, and age‐ and sex‐specific z‐score values were calculated using the World Health Organization growth standards. The median (interquartile range) iodine, IGF‐1, AD and LP concentrations were 232.5 (157.5–296.0) μg L−1, 15.7 (11.9–21.1) ng ml−1, 13.2 (5.1–29.8) mg L−1 and 1.16 (0.86–1.70) ng ml−1 in breast milk, respectively. No significant correlations were found between BMIC and IGF‐1, AD and LP concentrations during the first few days postpartum. In adjusted regression model, BMIC was positively associated with weight‐for‐length z score of infants. In the presence of IGF‐1, AD or LP, the coefficients of BMIC for weight‐for‐length z score of infants were β = .003 (P = .021), β = .002 (P = .028) or β = .003 (P = .013), respectively. No other anthropometric measurements were associated with iodine or growth‐ and obesity‐related hormones in breast milk. Our findings indicate that BMIC is a potential contributor to infants' growth status, independent of IGF‐1, AD or LP concentrations in breast milk. The underlying mechanisms remain to be elucidated.

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.

Relationship of Maternal Weight Status Before, During, and After Pregnancy with Breast Milk Hormone Concentrations.

The aim of this study was to test associations of prepregnancy BMI, gestational weight gain, oral glucose challenge test results, and postpartum weight loss as predictors of breast milk leptin, insulin, and adiponectin concentrations and whether these relationships vary over time. Milk was collected at 1 and 3months from 135 exclusively breastfeeding women from the longitudinal Mothers and Infants Linked for Healthy Growth (MILk) study. Hormones were assayed in skimmed samples using ELISA. Mixed-effects linear regression models were employed to assess main effects and effect-by-time interactions on hormone concentrations. In adjusted models, BMI was positively associated with milk leptin (P<0.001) and insulin (P=0.03) and negatively associated with milk adiponectin (P=0.02); however, the association was stronger with insulin and weaker with adiponectin at 3months than at 1month (time interaction P=0.017 for insulin and P=0.045 for adiponectin). Gestational weight gain was positively associated and postpartum weight loss was negatively associated with milk leptin (both P<0.001), independent of BMI. Oral glucose challenge test results were not associated with these milk hormone concentrations. Maternal weight status before, during, and after pregnancy contributes to interindividual variation in human milk composition. Continuing work will assess the role of these and other milk bioactive factors in altering infant metabolic outcomes.

Determinants of leptin in human breast milk: results of the Ulm SPATZ Health Study

Leptin in human breast milk has been implicated as a potential regulator of early-life metabolic programming. We comprehensively investigated the influence of maternal body mass index (BMI) and non-adiposity associated determinants on breast milk leptin concentration at 6 weeks, 6 months, and 1 year postpartum. The Ulm SPATZ Health Study consists of 1006 newborns and their mothers recruited from the general population in the University Medical Center Ulm, Southern Germany, in 2012/2013. Leptin concentration was measured in skimmed breast milk using commercially available ELISA (R&D System). Generalized estimating equations (GEE) accounting for repeated measures were used to calculate beta coefficients and 95% confidence intervals for association of potential demographic and lifestyle related determinants of hormone concentration with BMI-standardized leptin z-scores. Leptin concentration was measured in breast milk samples obtained from 694 mothers at approximately 6 weeks (n = 668), 6 months (n = 445), and 1 year (n = 69) postpartum. Differences in crude leptin concentrations between collection times were mostly explained by changes in BMI, breastfeeding frequency, and breast milk fat concentration. Positive associations between BMI and leptin were nonlinear and stronger among lower BMI subjects. Upon standardization, residual leptin concentrations were associated with maternal birth country, parity, age, and smoking history. Breast milk leptin concentration is primarily determined by adiposity-related factors. Studies using BMI as a proxy measure for adiposity should account for an observed nonlinear association with leptin, which may be especially important in determining causal associations with health outcomes from this and other adiposity-related hormones in breast milk.

MON-P267: Maternal Serum and Breast Milk Hormones and Weight Gain in İnfancy

MON-P267: Maternal Serum and Breast Milk Hormones and Weight Gain in İnfancy

Adiponectin, leptin and insulin in breast milk: associations with maternal characteristics and infant body composition in the first year of life.

Breastfeeding may protect against excessive weight gain during infancy. However, the breast milk components responsible for this effect are unknown. We examined the variation of three breast milk hormones (adiponectin, leptin and insulin) according to maternal characteristics and determined their association with infant body composition. We studied a representative subset of 430 breastfed infants in the CHILD birth cohort. Breast milk was collected at 4 months postpartum and hormone concentrations were measured using the MesoScale Discovery System. Weight-for-length (WFL) and body mass index (BMI) z-scores were calculated according to the World Health Organization reference standard from infant anthropometrics measured at 4 months and 1 year. Maternal BMI and demographics were self-reported. Breast milk hormone concentrations varied widely between mothers. The geometric mean (range) was 19.4 (3.7-74.4) ngml-1 for adiponectin; 361 (31-3968) pgml-1 for leptin; and 589 (53-5557) pgml-1 for insulin. Maternal BMI was positively correlated with breast milk insulin (r=+0.40, P<0.0001) and leptin (r=+0.71, P<0.0001), but not adiponectin (r=-0.02, P=0.68). Breast milk hormone concentrations were also associated with maternal ethnicity, parity and breastfeeding exclusivity at sample collection. Independent of these factors and maternal diabetes, smoking and breastfeeding duration, higher breast milk leptin was associated with lower infant WFL z-score at 4 months (β -0.67, 95% confidence interval (CI): -1.17, -0.17 for highest vs lowest quintile) and 1 year (β -0.58, 95% CI: -1.02, -0.14). Insulin showed a U-shaped association, with intermediate concentrations predicting the lowest infant WFL z-score at 4 months (β -0.51, 95% CI: -0.87, -0.15 for third vs lowest quintile) and 1 year (β -0.35, 95% CI: -0.66, -0.04). Similar results were seen with infant BMI. Breast milk adiponectin was not significantly associated with infant body composition. Breast milk hormone concentrations were associated with several fixed and modifiable maternal characteristics. Higher concentrations of leptin and intermediate concentrations of insulin were associated with lower infant WFL in the first year of life.

Associations between human breast milk hormones and adipocytokines and infant growth and body composition in the first 6 months of life.

Much is to be learnt about human breast milk (HBM). The purpose of this study is to extend our knowledge of HBM by investigating the role of maternal body mass index (BMI), sex and stage of lactation (month 1 vs. 6) on HBM insulin, glucose, leptin, IL-6 and TNF-α and their associations with infant body composition. Thirty-seven exclusively breastfeeding infants (n = 37; 16♀, 21♂), and their mothers (19-47 kg m-2 ) were studied at 1 and 6 months of lactation. Infants had body composition measured (using dual-energy X-ray absorptiometry) and HBM collected. A significant interaction between maternal BMI and infant sex on insulin levels (p = 0.0322) was observed such that insulin was 229% higher in obese mothers nursing female infants than in normal weight mothers nursing female infants and 179% higher than obese mothers nursing male infants. For leptin, a significant association with BMI category was observed (p < 0.0001) such that overweight and obese mothers had 96.5% and 315.1% higher leptin levels than normal weight mothers, respectively. Leptin was also found to have a significant (p = 0.0004) 33.7% decrease from months 1 to 6, controlling for BMI category and sex. A significant inverse relationship between month 1 leptin levels and infant length (p = 0.0257), percent fat (p = 0.0223), total fat mass (p = 0.0226) and trunk fat mass (p = 0.0111) at month 6 was also found. No associations or interactions were observed for glucose, TNF-α or IL-6. These data demonstrate that maternal BMI, infant sex and stage of lactation affect the compositional make-up of insulin and leptin.

Impact of maternal BMI and sampling strategy on the concentration of leptin, insulin, ghrelin and resistin in breast milk across a single feed: a longitudinal cohort study

ObjectivesWe tested the hypothesis that there is a positive association between maternal body mass index (BMI) and the concentration of appetite-regulating hormones leptin, insulin, ghrelin and resistin in breast milk....

Expressed Breast Milk Volume May Need to Be Considered in Studies of Lactational Programming of Obesity

There is increased interest in “lactational programming” as a potential mechanism by which maternal and offspring obesity are linked; that is, there are bioactive hormonal and other factors in milk that vary by maternal nutritional status and can alter infant growth rate. However, existing studies often do not consider whether breast milk sample volume could play a role in these associations.ObjectivesWe tested whether the volume of milk collected from mothers for hormone assays was associated with maternal pre‐pregnancy body mass index (BMI) and gestational weight gain. Secondary analyses examined the associations of breast milk volume with infant weight status.MethodsParticipants were 54 exclusively breastfeeding mother‐infant dyads (average maternal age 30.9 ± 3.8 years, 91% White), enrolled in the ongoing Mothers and Infants LinKed for Healthy Growth (MILK) study. Maternal and infant anthropometrics and breast milk volume were assessed at one and three months postpartum. Pre‐pregnancy BMI and gestational weight gain were calculated using first prenatal visit weight, measured height, and delivery weight. Infant weight and length were measured and converted to WHO Z‐scores. Milk volume was assessed by having mothers provide a single complete breast expression using an electric breast pump (Medela, Inc.) exactly two hours after feeding their infant until volitionally satisfied. Linear regression models examined associations of maternal pre‐pregnancy BMI and gestational weight gain with milk volume, after controlling for age, parity, education, and race. Milk volume was also examined as a predictor of infant weight and length status.ResultsAverage pre‐pregnancy BMI was 25.6 ± 4.7 kg/m2 (53.7% normal weight, 25.9% overweight, 20.4% obese), and mean gestational weight gain was 14.1 ± 5.2 kg. Breast milk volume increased from 68.4 ± 32.0 ml at one month postpartum to 70.3 ± 35.1 ml at three months. An inverse association was observed between pre‐pregnancy BMI and milk volume at three months only (β=−3.13, p=0.006). Gestational weight gain was not associated with milk volume at one or three months. We also found that milk volume at one month was positively associated with weight for‐age Z‐scores at one (β= 0.01, p=0.015) and three months (β= 0.01, p=0.023). Milk volume was not associated with length‐for‐age or weight‐for‐length Z‐scores.ConclusionsPreliminary analyses from the MILK study showed that greater pre‐pregnancy BMI was associated with a reduction in milk volume from a standardized milk expression at three months postpartum. Milk volumes were also positively associated with weight‐for‐age Z‐scores at one and three months postpartum. If milk hormone concentrations are found to vary with milk volume produced, our results indicate the need to control for this factor when examining the role of breast milk hormones in the transmission of obesity risk from mother to offspring.Support or Funding InformationR01 HD080444 (National Institute for Child Health and Development)

Niveles de adiponectina en leche materna de madres con sobrepeso/obesidad y con peso normal del área metropolitana de Monterrey, México

BackgroundGiven the current epidemic of childhood obesity, it has become increasingly important to understand the risks and protective factors associated with this disease. Breastfeeding has been identified as a protective factor; however, the mechanism responsible has not been elucidated. One of the current theories analyzes the role of hormones in breast milk, with special emphasis on adiponectin. This study aims to compare adiponectin levels in breast milk of mothers with normal weight with those in breast milk of overweight/obese mothers as well as to correlate these levels with the infant's weight gain. MethodsForty samples of breast milk were analyzed for adiponectin levels using ELISA, 20 from mothers with normal weight and 20 from overweight/obese mothers. ResultsAdiponectin levels were lower in breast milk obtained from overweight/obese mothers than in breast milk from mothers with normal weight (p <0.05). When comparing infant weight gain, those fed with breast milk containing higher concentrations of adiponectin had a lower weight gain than those fed with breast milk containing low levels of the hormone (p <0.05). ConclusionsThere is a strong negative correlation between mothers’ BMI and adiponectin levels in breast milk. Mothers with a higher BMI had lower adiponectin levels in their breast milk. There is also a negative relationship between adiponectin levels in breast milk and weight gain of breastfed infants. Infants breast fed with adiponectin-rich breast milk had a lower weight gain.

Effect of maternal body mass index on hormones in breast milk: a systematic review.

BackgroundMaternal Body Mass Index (BMI) is positively associated with infant obesity risk. Breast milk contains a number of hormones that may influence infant metabolism during the neonatal period; these may have additional downstream effects on infant appetite regulatory pathways, thereby influencing propensity towards obesity in later life.ObjectiveTo conduct a systematic review of studies examining the association between maternal BMI and the concentration of appetite-regulating hormones in breast milk.MethodPubmed was searched for studies reporting the association between maternal BMI and leptin, adiponectin, insulin, ghrelin, resistin, obestatin, Peptide YY and Glucagon-Like Peptide 1 in breast milk.ResultsTwenty six studies were identified and included in the systematic review. There was a high degree of variability between studies with regard to collection, preparation and analysis of breast milk samples. Eleven of fifteen studies reporting breast milk leptin found a positive association between maternal BMI and milk leptin concentration. Two of nine studies investigating adiponectin found an association between maternal BMI and breast milk adiponectin concentration; however significance was lost in one study following adjustment for time post-partum. No association was seen between maternal BMI and milk adiponectin in the other seven studies identified. Evidence for an association between other appetite regulating hormones and maternal BMI was either inconclusive, or lacking.ConclusionsA positive association between maternal BMI and breast milk leptin concentration is consistently found in most studies, despite variable methodology. Evidence for such an association with breast milk adiponectin concentration, however, is lacking with additional research needed for other hormones including insulin, ghrelin, resistin, obestatin, peptide YY and glucagon-like peptide-1. As most current studies have been conducted with small sample sizes, future studies should ensure adequate sample sizes and standardized methodology.

The Study of Breast Milk IGF-1, Leptin, Ghrelin and Adiponectin Levels as Possible Reasons of High Weight Gain in Breast-Fed Infants

Background: Excessive consumption of protein that leads to increased blood levels of insulin-like growth factor-1 (IGF-1) is an important risk factor for high growth velocity and obesity in formula-fed infants. However, it is not clear whether these factors can explain the high growth velocity in breast-fed infants. Aim: To study the possible links between the growth velocity in breast-fed infants and the levels of protein, IGF-1 and other hormones, which regulate energy homeostasis, in mothers' breast milk. Methods: We studied 103 mother-infant pairs. Their daily breast milk intake and level of IGF-1, leptin, ghrelin, adiponectin, protein and fat in breast milk were measured at 1, 2 and 3 months of lactation. The infant group was divided into three subgroups of low, normal and high weight gain tertiles. Results: The breast milk consumed by the infants with high weight gain contained higher levels of IGF-1 than that consumed by those with low weight gain at all periods studied (p = 0.032 at 3 months of lactation), and ghrelin levels were higher at 1 and 2 months and leptin levels at 2 and 3 months of lactation (p < 0.05). A positive correlation was observed between the breast milk IGF-1 level and infant weight gain (r = 0.294, p = 0.043). Total daily breast milk, fat and hormone intake was also higher in the high weight gain group compared to the low weight gain group. Conclusion: One of the reasons for the high growth velocity in breast-fed infants may be the enhanced levels of the studied hormones in breast milk.

Presence and dynamics of leptin, GLP‐1, and PYY in human breast milk at early postpartum

Objective: The presence of appetite hormones, namely glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and leptin in breast milk may be important in infant feeding regulation and infant growth. This study evaluated whether concentrations of GLP-1, PYY, and leptin change across a single feeding (from fore- to hindmilk), and are associated with maternal and infant anthropometrics.Design and Methods: Thirteen postpartum women (mean ± SD: 25.6 ± 4.5 years, 72.0 ± 11.9 kg) provided fore- and hindmilk samples 4-5 weeks after delivery and underwent measurements of body weight and composition by Dual X-ray Absorptiometry. GLP-1, PYY, and leptin concentrations were measured using radioimmunoassay, and milk fat content was determined by creamatocrit.Results: Concentration of GLP-1 and content of milk fat was higher in hindmilk than foremilk (P ≤ 0.05). PYY and leptin concentrations did not change between fore- and hindmilk. Both leptin concentration and milk fat content were correlated with indices of maternal adiposity, including body mass index (r = 0.65-0.85, P < 0.02), and fat mass (r = 0.65-0.84, P < 0.02). Hindmilk GLP-1 was correlated with infant weight gain from birth to 6 months (r = −0.67, P = 0.034).Conclusion: The presence of appetite hormones in breast milk may be important in infant appetite and growth regulation.