Human milk composition: nutrients and bioactive factors

Longitudinal evolution of the concentration of gangliosides GM3 and GD3 in human milk

It has been reported that dietary gangliosides may have an important role in preventing infections and in brain development during early infancy. However, data related to the evolution of their concentration over the different stages of lactation are scarce. Liquid chromatography coupled with electrospray ionization high resolution mass spectrometer (LC/ESI-HR-MS) has been optimized to quantify the two major ganglioside classes, i.e., aNeu5Ac(2-8)aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer (GD3) and aNeu5Ac(2-3)bDGalp(1-4)bDGlcp(1-1)Cer (GM3) in human milk. Gangliosides were extracted using chloroform and methanol, further purified by solid-phase extraction and separated by reversed-phase liquid chromatography. Repeatability, intermediate reproducibility, and recovery values were assessed to validate the method. In human milk, GD3 and GM3 could be quantified at the level of 0.1 and 0.2 μg/mL, respectively, with relative standard deviation of repeatability [CV(r)] and intermediate reproducibility [CV(iR)] values ranging from 1.9 to 15.0 % and 1.9 to 22.5 %, respectively. The described method was used to quantify GD3 and GM3 in human milk samples collected from 450 volunteers between 0 and 11 days and at 30, 60 and 120 days postpartum, providing for the first time the concentration of these minor lipids in a large cohort. The content of total gangliosides ranged from 8.1 and 10.7 μg/mL and the mean intake of gangliosides in infants 30, 60 and 120 days postpartum could be estimated at about 5.5, 7.0 and 8.6 mg of total gangliosides per day, respectively, when infants were exclusively breastfed.

Sugar-sweetened soda consumption and risk of developing rheumatoid arthritis in women

BACKGROUND

Sugar-sweetened soda consumption is consistently associated with an increased risk of several chronic inflammatory diseases such as type 2 diabetes and cardiovascular diseases. Whether it plays a role in the development of rheumatoid arthritis (RA), a common autoimmune inflammatory disease, remains unclear.

OBJECTIVE

The aim was to evaluate the association between sugar-sweetened soda consumption and risk of RA in US women.

DESIGN

We prospectively followed 79,570 women from the Nurses' Health Study (NHS; 1980-2008) and 107,330 women from the NHS II (1991-2009). Information on sugar-sweetened soda consumption (including regular cola, caffeine-free cola, and other sugar-sweetened carbonated soda) was obtained from a validated food-frequency questionnaire at baseline and approximately every 4 y during follow-up. Incident RA cases were validated by medical record review. Time-varying Cox proportional hazards regression models were used to calculate HRs after adjustment for confounders. Results from both cohorts were pooled by an inverse-variance-weighted, fixed-effects model.

RESULTS

During 3,381,268 person-years of follow-up, 857 incident cases of RA were documented in the 2 cohorts. In the multivariable pooled analyses, we found that women who consumed ≥1 serving of sugar-sweetened soda/d had a 63% (HR: 1.63; 95% CI: 1.15, 2.30; P-trend = 0.004) increased risk of developing seropositive RA compared with those who consumed no sugar-sweetened soda or who consumed <1 serving/mo. When we restricted analyses to those with later RA onset (after age 55 y) in the NHS, the association appeared to be stronger (HR: 2.64; 95% CI: 1.56, 4.46; P-trend < 0.0001). No significant association was found for sugar-sweetened soda and seronegative RA. Diet soda consumption was not significantly associated with risk of RA in the 2 cohorts.

CONCLUSION

Regular consumption of sugar-sweetened soda, but not diet soda, is associated with increased risk of seropositive RA in women, independent of other dietary and lifestyle factors.

A systematic review and meta-analysis of the nutrient content of preterm and term breast milk

Background

Breast milk nutrient content varies with prematurity and postnatal age. Our aims were to conduct a meta-analysis of preterm and term breast milk nutrient content (energy, protein, lactose, oligosaccharides, fat, calcium, and phosphorus); and to assess the influence of gestational and postnatal age. Additionally we assessed for differences by laboratory methods for: energy (measured vs. calculated estimates) and protein (true protein measurement vs. the total nitrogen estimates).

Methods

Systematic review results were summarized graphically to illustrate the changes in composition over time for term and preterm milk. Since breast milk fat content varies within feeds and diurnally, to obtain accurate estimates we limited the meta-analyses for fat and energy to 24-hour breast milk collections.

Results

Forty-one studies met the inclusion criteria: 26 (843 mothers) preterm studies and 30 (2299 mothers) term studies of breast milk composition. Preterm milk was higher in true protein than term milk, with differences up to 35% (0.7 g/dL) in colostrum, however, after postnatal day 3, most of the differences in true protein between preterm and term milk were within 0.2 g/dL, and the week 10–12 estimates suggested that term milk may be the same as preterm milk by that age. Colostrum was higher than mature milk for protein, and lower than mature milk for energy, fat and lactose for both preterm and term milk. Breast milk composition was relatively stable between 2 and 12 weeks. With milk maturation, there was a narrowing of the protein variance. Energy estimates differed whether measured or calculated, from −9 to 13%; true protein measurement vs. the total nitrogen estimates differed by 1 to 37%.

Conclusions

Although breast milk is highly variable between individuals, postnatal age and gestational stage (preterm versus term) were found to be important predictors of breast milk content. Energy content of breast milk calculated from the macronutrients provides poor estimates of measured energy, and protein estimated from the nitrogen over-estimates the protein milk content. When breast milk energy, macronutrient and mineral content cannot be directly measured the average values from these meta-analyses may provide useful estimates of mother’s milk energy and nutrient content.

Priming for health: gut microbiota acquired in early life regulates physiology, brain and behaviour

The infant gut microbiome is dynamic, and radical shifts in composition occur during the first 3 years of life. Disruption of these developmental patterns, and the impact of the microbial composition of our gut on brain and behaviour, has attracted much recent attention. Integrating these observations is an important new research frontier.

CONCLUSION

Early-life perturbations of the developing gut microbiota can impact on the central nervous system and potentially lead to adverse mental health outcomes.

Repeatability of gastric volume measurements and intragastric content using ultrasound in preterm infants

OBJECTIVES

The aim of the present study was to determine whether serial gastric volumes and intragastric curding are repeatable within individual preterm infants when given sequential feeds of the same volume and composition. Infant and feeding characteristics that may influence differences in measured gastric volumes, echogenicity, and intragastric curding were also explored.

METHODS

Ultrasound images were used to calculate gastric volumes and to rate echogenicity and intragastric curding for 20 infants. A total of 29 paired feeds of the same volume and composition were monitored prefeed and postfeed and at 30-minute intervals thereafter. Statistical comparisons of paired gastric volume measurements and agreement between echogenicity and curding ratings were made for each time point. Analyses of factors that influence discrepancies between volume measurements and between curding ratings were performed.

RESULTS

Paired gastric volume measurements were repeatable (intraclass correlation coefficient [ICC] = 0.971, 0.938 < ICC < 0.987). Most (75%) discrepancies were <2 mL and increased over time, although volume differences were small. Overall moderate levels of consistency were observed for ratings of echogenicity (κ = 0.44), and curd presence (κ ≤ 0.65), density (κ = 0.41), and volume (κ = 0.47). Gastric emptying during feed delivery is influenced with infant positioning, fortification of breast milk, and feeding frequency.

CONCLUSIONS

For preterm infants serial gastric volumes are repeatable and ratings of intragastric echogenicity and curding are moderately consistent when fed milk of the same volume and composition. Ultrasound has the potential to further explore factors that influence gastric emptying in the preterm infant.

Considerations in meeting protein needs of the human milk-fed preterm infant

Preterm infants provided with sufficient nutrition to achieve intrauterine growth rates have the greatest potential for optimal neurodevelopment. Although human milk is the preferred feeding for preterm infants, unfortified human milk provides insufficient nutrition for the very low-birth-weight infant. Even after fortification with human milk fortifier, human milk often fails to meet the high protein needs of the smallest preterm infants, and additional protein supplementation must be provided. Although substantial evidence exists to support quantitative protein goals for human milk-fed preterm infants, the optimal type of protein for use in human milk fortification remains uncertain. This question was addressed through a PubMed literature search of prospective clinical trials conducted since 1990 in preterm or low-birth-weight infant populations. The following 3 different aspects of protein quality were evaluated: whey-to-casein ratio, hydrolyzed versus intact protein, and bovine milk protein versus human milk protein. Because of a scarcity of current studies conducted with fortified human milk, studies examining protein quality using preterm infant formulas were included to address certain components of the clinical question. Twenty-six studies were included in the review study. No definite advantage was found for any specific whey-to-casein ratio. Protein hydrolyzate products with appropriate formulations can support adequate growth and biochemical indicators of nutrition status and may reduce gastrointestinal transit time, gastroesophageal reflux events, and later incidence of atopic dermatitis in some infants. Plasma amino acid levels similar to those of infants fed exclusive human milk-based diets can be achieved with products composed of a mixture of bovine proteins, peptides, and amino acids formulated to replicate the amino acid composition of human milk. Growth and biochemical indicators of nutrition status are similar for infants fed human milk fortified with human milk protein and bovine milk protein.

The impact of breastfeeding on lung development and function: a systematic review

With the global trend of increasing asthma and allergic disorders there is strong interest regarding early life nutrition as a potentially modifiable risk factor for lung disease. This systematic review includes 10 studies that assessed the effect of breastfeeding on lung growth and function. The review found breastfeeding to be beneficial for lung function, with the most consistent effect on increased forced vital capacity. There was no clear evidence that the relationship between breastfeeding and lung function was mediated through other factors. Furthermore, the findings from the few studies that investigated if maternal asthma modified the effect of breastfeeding on lung function were inconsistent. Further research is needed to determine the specific details such as duration and type (exclusive vs partial) of breastfeeding that leads to improved lung function.

Correlation between lactoferrin and beneficial microbiota in breast milk and infant's feces

Lactoferrin (LF) is a natural component of human milk with antimicrobial, immunostimulatory and immunomodulatory properties. Several in vitro studies suggest that LF could promote an environment in the gut of neonates that favors colonization with beneficial bacteria. However, clinical studies on the correlation between the concentration of LF in breast milk and feces of infants and the gut microbiota in infants are lacking. In our study we analyzed the content of LF and the microbiota of breast milk and feces of infants of 48 mother-infant pairs (34 full-term and 14 pre-term infants) at birth and 30 days after delivery. In the term group, a significant decrease of mean LF concentration between colostrum (7.0 ± 5.1 mg/ml) and mature milk (2.3 ± 0.4 mg/ml) was observed. In pre-term group, breast milk LF levels were similar to those observed in full-term group. Fecal LF concentration of healthy infants was extremely high both in term and pre-term infants, higher than the amount reported in healthy children and adults. In term infants mean fecal LF levels significantly increased from birth (994 ± 1,828 μg/ml) to 1 month of age (3,052 ± 4,323 μg/ml). The amount of LF in the feces of 30 day-old term infants was significantly associated with maternal mature milk LF concentration (p = 0.030) confirming that breast milk represents the main source of LF found in the gut of infants. A linear positive correlation between colostrum and mature milk LF concentration was observed (p = 0.008) indicating that milk LF levels reflect individual characteristics. In pre-term infants higher mean concentrations of fecal LF at birth (1,631 ± 2,206 μg/ml) and 30 days after delivery (7,633 ± 9,960 μg/ml) were observed in comparison to full-term infants. The amount of fecal bifidobacteria and lactobacilli resulted associated with the concentration of fecal LF 3 days after delivery (p = 0.017 and p = 0.026, respectively). These results suggest that high levels of fecal LF in neonates, particularly in the first days of life, could represent an important factor in the initiation, development and/or composition of the neonatal gut microbiota. Since early host-microbe interaction is a crucial component of healthy immune and metabolic programming, high levels of fecal LF in neonates may beneficially contribute to the immunologic maturation and well-being of the newborn, especially in pre-term infants.

Metal ions bound to the human milk immunoglobulin A: metalloproteomic approach

The presence of calcium, iron, and zinc bound to human milk secretory IgA (sIgA) was investigated. The sIgA components were first separated by two-dimensional polyacrylamide gel electrophoresis and then identified by electrospray ionization-tandem mass spectrometry (ESI MS MS). The metal ions were detected by flame atomic absorption spectrometry after acid mineralization of the spots. The results showed eight protein spots corresponding to the IgA heavy chain constant region. Another spot was identified as the transmembrane secretory component. Calcium was bound to both the transmembrane component and the heavy chain constant region, while zinc was bound to the heavy chain constant region and iron was not bound with the identified proteins. The association of a metal ion with a protein is important for a number of reasons, and therefore, the findings of the present study may lead to a better understanding of the mechanisms of action and of additional roles that sIgA and its components play in human milk.

Human breast milk and the gastrointestinal innate immune system

The gastrointestinal (GI) tract is a large potential portal for multiple infectious agents to enter the human body. The GI system performs multiple functions as part of the neonate's innate immune system, providing critical defense during a vulnerable period. Multiple mechanisms and actions are enhanced by the presence of human breast milk. Bioactive factors found in human milk work together to create and maintain an optimal and healthy environment, allowing the intestines to deliver ideal nutrition to the host and afford protection by a variety of mechanisms.

Norovirus GII.4 antibodies in breast milk and serum samples: their role preventing virus-like particles binding to their receptors

BACKGROUND

Norovirus GII.4 genotype is a leading cause of nonbacterial gastroenteritis in infants. Effective vaccines against noroviruses are not yet available, enhancing the interest of the protection mechanisms elicited by breast milk that may contain norovirus-specific antibodies and histo-blood group antigens. The aims of our study were to analyze norovirus GII.4-specific antibodies in breast milk and serum and to assess their blocking activity on recombinant norovirus virus-like particles (VLPs) binding to saliva.

METHODS

Mature milk and serum from 108 mothers were analyzed for specific IgA to norovirus GII.4-2006b and for their blocking activity on the binding of norovirus GII.4-2006b VLPs to fucosyltransferase FUT2-positive and negative saliva. Norovirus GII.4-2006b-specific IgG antibodies were also analyzed in serum samples.

RESULTS

Higher specific IgA titers were detected in mature milk (75%) than in serum samples (62%), showing a correlation between both results (ρ = 0.427, P = 0.000). However, only 56.3% of the serum samples contained norovirus-specific IgG. Almost all mature milk samples (99.1%) inhibited the binding of norovirus VLPs to FUT2-negative saliva; however, only 25% did so to FUT2-positive saliva (P = 0.000). Ninety percent of serum samples inhibited the binding of norovirus VLPs to FUT2-negative saliva.

CONCLUSIONS

Breast milk inhibits norovirus GII.4-2006b VLPs binding to receptors in saliva, and anti-norovirus IgA antibodies are only partly responsible for this activity. The FUT2 status of the receptor seems to be a strong predictor of this effect, but more studies to ascertain the participation of histo-blood group antigens in the protection against norovirus infections elicited by breast milk are required.

The future of yogurt: scientific and regulatory needs

Lactation biology, microbial selection, and human diversity are central themes that could guide investment in scientific research, industrial innovation, and regulatory policy oversight to propel yogurt into the central role for health-promoting food products. The ability of yogurt to provide the nourishing properties of milk together with the live microorganisms from fermentation provides a unique combination of food assets. Academic research must now define the various targets on which these biological assets act to improve health and develop the metrics that can quantitatively document their benefits. The food industry must reconcile that yogurt and its microorganisms cannot be expected to provide measurable benefits for all consumers, at all doses, and at all times. A supportive regulatory oversight must demand safety and yet encourage innovations that support a value proposition for yogurt in health. Health valuation in the marketplace will be driven by parallel innovations, including accurate assessment technologies, validated microbial ingredients, and health-aware consumers.

Impact of breast-feeding and high- and low-protein formula on the metabolism and growth of infants from overweight and obese mothers

BACKGROUND

The combination of maternal obesity in early pregnancy and high protein intake in infant formula feeding might predispose to obesity risk in later life.

METHODS

This study assesses the impact of breast- or formula-feeding (differing in protein content by 1.65 or 2.7 g/100 kcal) on the metabolism of term infants from overweight and obese mothers. From birth to 3 mo of age, infants received exclusively either breast- or starter formula-feeding and until 6 mo, exclusively either a formula designed for this study or breast-feeding. From 6 to 12 mo, infants received complementary weaning food. Metabonomics was conducted on the infants' urine and stool samples collected at the age of 3, 6, and 12 mo.

RESULTS

Infant formula-feeding resulted in higher protein-derived short-chain fatty acids and amino acids in stools. Urine metabonomics revealed a relationship between bacterial processing of dietary proteins and host protein metabolism stimulated with increasing protein content in the formula. Moreover, formula-fed infants were metabolically different from breast-fed infants, at the level of lipid and energy metabolism (carnitines, ketone bodies, and Krebs cycle).

CONCLUSION

Noninvasive urine and stool metabolic monitoring of responses to early nutrition provides relevant readouts to assess nutritional requirements for infants' growth.

An evolving scientific basis for the prevention and treatment of pediatric obesity

The 2013 Pennington Biomedical Research Center's Scientific Symposium focused on the treatment and management of pediatric obesity and was designed to (i) review recent scientific advances in the prevention, clinical treatment and management of pediatric obesity, (ii) integrate the latest published and unpublished findings and (iii) explore how these advances can be integrated into clinical and public health approaches. The symposium provided an overview of important new advances in the field, which led to several recommendations for incorporating the scientific evidence into practice. The science presented covered a range of topics related to pediatric obesity, including the role of genetic differences, epigenetic events influenced by in utero development, pre-pregnancy maternal obesity status, maternal nutrition and maternal weight gain on developmental programming of adiposity in offspring. Finally, the relative merits of a range of various behavioral approaches targeted at pediatric obesity were covered, together with the specific roles of pharmacotherapy and bariatric surgery in pediatric populations. In summary, pediatric obesity is a very challenging problem that is unprecedented in evolutionary terms; one which has the capacity to negate many of the health benefits that have contributed to the increased longevity observed in the developed world.

The Role of Maternal Breast Milk in Preventing Infantile Diarrhea in the Developing World

Multiple interventions have been designed to decrease mortality and disability in children. Among these, breastfeeding is the most cost effective intervention for protecting children against diarrhea and all causes of mortality. Human milk is uniquely suited to the human infant, both in its nutritional composition and in the nonnutritive bioactive factors that promote survival and healthy development. Suboptimal breastfeeding has been linked with numerous adverse child health outcomes including increased incidence of diarrhea and pneumonia. This review provides an update regarding recent studies on the effect of breastfeeding on diarrhea morbidity and mortality in children in developing countries, describes major human milk components responsible for this protective effect (oligosaccharides, secretory immunoglobulins, lactoferrin, bacterial microbiota, etc.), and highlights areas for future research in this topic. Breastfeeding promotion remains an intervention of enormous public health potential to decrease global mortality and promote better growth and neurodevelopment in children.

Impact of maternal diet on human milk composition and neurological development of infants

Maternal nutrition has little or no effect on many nutrients in human milk; for others, human milk may not be designed as a primary nutritional source for the infant; and for a few, maternal nutrition can lead to substantial variations in human milk quality. Human milk fatty acids are among the nutrients that show extreme sensitivity to maternal nutrition and are implicated in neurological development. Extensive development occurs in the infant brain, with growth from ∼ 350 g at birth to 925 g at 1 y, with this growth including extensive dendritic and axonal arborization. Transfer of n-6 (omega-6) and n-3 (omega-3) fatty acids from the maternal diet into human milk occurs with little interconversion of 18:2n-6 to 20:4n-6 or 18:3n-3 to docosahexaenoic acid (DHA) and little evidence of mammary gland regulation to maintain individual fatty acids constant with varying maternal fatty acid nutrition. DHA has gained attention because of its high concentrations and roles in the brain and retina. Studies addressing DHA intakes by lactating women or human milk amounts of DHA at levels above those typical in the United States and Canada on infant outcomes are inconsistent. However, separating effects of the fatty acid supply in gestation or in the weaning diet from effects on neurodevelopment solely due to human milk fatty acids is complex, particularly when neurodevelopment is assessed after the period of exclusive human milk feeding. Information on infant fatty acid intakes, including milk volume consumed and energy density, will aid in understanding of the human milk fatty acids that best support neurological development.

Executive summary: Evaluating the evidence base to support the inclusion of infants and children from birth to 24 mo of age in the Dietary Guidelines for Americans--"the B-24 Project"

The Dietary Guidelines for Americans (DGA) are the cornerstone of US government efforts to promote health and prevent disease through diet and nutrition. The DGA currently provides guidelines for ages ≥ 2 y. In an effort to determine the strength of the evidence to support the inclusion of infants and children from birth to age 24 mo, the partner agencies led by the Department of Health and Human Services Office of Disease Prevention and Health Promotion and the USDA Center for Nutrition Program and Policy initiated the project entitled "Evaluating the evidence base to support the inclusion of infants and children from birth to 24 months of age in the Dietary Guidelines for Americans--the B-24 Project." This project represents the first step in the process of applying systematic reviews to the process of deciding whether the evidence is sufficient to include this age group in future editions of the DGA. This supplement includes the B-24 Executive Summary, which describes the B-24 Project and the deliberations of the 4 working groups during the process of developing priority topics for the systematic review, and a research agenda to address the critical gaps. Also included in this supplement issue is an article on the Nutrition Evidence Library methodology for developing systematic review questions and articles from the invited content presenters at the B-24 Prime meeting.

miRNA profiling reveals a potential role of milk stasis in breast carcinogenesis

The tumor microenvironment plays an important role in breast carcinogenesis. Milk acts as an important microenvironment of breast cancer, but its role in breast carcinogenesis is largely unknown. Milk stasis may exist in the breast for a number of years after breastfeeding. In the present study, we reported the first microRNA (miRNA) profiling of milk from patients with milk stasis. We identified 266 known miRNAs and 271 novel miRNAs in 10 milk stasis only samples, 271 known miRNAs and 140 novel miRNAs in 10 milk stasis plus breast neoplasm samples by deep sequencing. miRNA profiles were different between the two groups. Furthermore, nine tumor suppressor miRNAs such as miR-29a, miR-146 and miR-223 were significantly downregulated, while seven oncogenic miRNAs such as miR-451, miR-486, miR-107, miR-92 and miR-10 were significantly upregulated in the milk of milk stasis plus neoplasm patients. Three of the identified miRNAs (miR-140, miR-21 and let-7a) were selected using real-time PCR, confirming that these miRNAs were highly expressed. The results also showed that the three miRNAs detected were more abundant in the milk than in the blood. In summary, the data suggested that miRNAs in milk from milk stasis patients may contribute to breast carcinogenesis and that they are more sensitive biomarkers for breast cancer than miRNAs in the blood.

Probiotics tailored to the infant: a window of opportunity

Initial neonatal gut colonization is a crucial stage for developing a healthy physiology, beneficially influenced by breast-feeding. Breast milk has been shown not only to provide nutrients and bioactive immunological compounds, but also commensal bacteria, including gut-associated anaerobic bacteria such as Bifidobacterium species. Infant formulas are increasingly supplemented with probiotic bacteria despite uncertainties regarding their efficacy, and lack of mechanistic understanding. Breast milk may be a valuable source of such bacteria which, upon validation of their mechanism of action, might open a window of opportunity for developing probiotic-supplemented infant formula with proven efficacy.

Using breast milk to assess breast cancer risk: the role of mass spectrometry-based proteomics

Although mammography and treatment advances have led to declines in breast cancer mortality in the United States, breast cancer remains a major cause of morbidity and mortality. Breast cancer in young women is associated with increased mortality and current methods of detecting breast cancers in this group of women have known limitations. Tools for accurately assessing personal breast cancer risk in young women are needed to identify those women who would benefit the most from earlier intervention. Proteomic analysis of breast milk could identify biomarkers of breast cancer risk and provide a tool for identifying women at increased risk. A preliminary analysis of milk from four women provides a proof of concept for using breast milk to assess breast cancer risk.

Maternal blood, plasma, and breast milk lead: lactational transfer and contribution to infant exposure

BACKGROUND

Human milk is a potential source of lead exposure. Yet lactational transfer of lead from maternal blood into breast milk and its contribution to infant lead burden remains poorly understood.

OBJECTIVES

We explored the dose-response relationships between maternal blood, plasma, and breast milk to better understand lactational transfer of lead from blood and plasma into milk and, ultimately, to the breastfeeding infant.

METHODS

We measured lead in 81 maternal blood, plasma, and breast milk samples at 1 month postpartum and in 60 infant blood samples at 3 months of age. Milk-to-plasma (M/P) lead ratios were calculated. Multivariate linear, piecewise, and generalized additive models were used to examine dose-response relationships between blood, plasma, and milk lead levels.

RESULTS

Maternal lead levels (mean±SD) were as follows: blood: 7.7±4.0 μg/dL; plasma: 0.1±0.1 μg/L; milk: 0.8±0.7 μg/L. The average M/P lead ratio was 7.7 (range, 0.6-39.8) with 97% of the ratios being >1. The dose-response relationship between plasma lead and M/P ratio was nonlinear (empirical distribution function=6.5, p=0.0006) with the M/P ratio decreasing by 16.6 and 0.6 per 0.1 μg/L of plasma lead, respectively, below and above 0.1 μg/L plasma lead. Infant blood lead level (3.4±2.2 μg/dL) increased by 1.8 μg/dL per 1 μg/L milk lead (p<0.0001, R2=0.3).

CONCLUSIONS

The M/P ratio for lead in humans is substantially higher than previously reported, and transfer of lead from plasma to milk may be higher at lower levels of plasma lead. Breast milk is an important determinant of lead burden among breastfeeding infants.

Intestinal colonization and programming of the intestinal immune response

Initial bacterial colonization of the gut is a vital component of the development of the gastrointestinal tract, particularly mucosal immune protection, during the neonatal period. Newborn infants in their protected intrauterine environment are suddenly thrust into a highly contaminated extrauterine state. Although mucosal host defenses have developed in utero during fetal maturation because of the stimulation of ingested trophic factors in amniotic fluid, actual active protection only occurs when colonizing bacteria stimulate the gut mucosal barrier. Colonization evolves over a period of about 1 year and is dependent on the mode of delivery, use of perinatal antibiotics, age at birth, and infant feeding. A fully colonized gut consists of 10(14) bacteria, establishes a symbiotic relationship with the host and insures normal development and immune homeostasis. Colonizing bacteria can also affect the epithelial mucosal barrier and the innate and adaptive immune systems. Disruption of normal colonization, dysbiosis, is associated with increased expression of disease. Evidence exists that the use of probiotics with dysbiosis may prevent disease expression.

Preeclampsia alters milk neurotrophins and long chain polyunsaturated fatty acids

OBJECTIVE

To examine the levels of breast milk neurotrophins 1.5, 3.5, and 6 months of lactation and long chain polyunsaturated fatty acids (LCPUFA) at day 3, 1.5, 2.5, 3.5 and 6 months of lactation in mothers with preeclampsia and compare them with normotensive women. Their associations with growth parameters in children are also examined.

METHODS

Women with preeclampsia (n=101) and normotensive women (n=144) with singleton pregnancies were recruited for this study. Milk samples were collected and anthropometry was recorded at the first 6 months. The LCPUFA composition of milk samples was analyzed by using gas chromatography at all time points and neurotrophins were analyzed at 1.5, 3.5 and 6 months by Emax Immuno Assay System using Promega kits.

RESULTS

Milk DHA levels were higher at day 3 (9.5%), and 1.5 (23%) and 3.5 (40%) months in mothers with preeclampsia as compared to controls. Milk nerve growth factor (NGF) levels were lower in preeclampsia group as compared to control group at 1.5 (20%) and 3.5 months (27.7%). Milk brain derived neurotrophic factor (BDNF) levels were lower at 1.5 months (10.5%) in the preeclampsia group as compared to control group.

CONCLUSION

The present study suggests that there is a differential regulation of DHA and neurotrophins in breast milk in preeclampsia and are associated with growth parameters of children. Future studies should explore the associations between milk LCPUFA, neurotrophins with neurodevelopment in children.

Biologic therapies and pregnancy: the story so far

Biologic therapies have revolutionized treatment outcomes for patients with inflammatory arthritis. However, there remains a concern regarding their safety during conception, pregnancy and breastfeeding. Data on the safety of these treatments are largely limited to uncontrolled case reports. Collective evidence from many hundreds of pregnancies in inflammatory arthritis and IBD have suggested that exposure to anti-TNF therapies at the time of conception or during the first trimester does not result in an increased risk of adverse pregnancy and fetal outcomes. Monoclonal antibodies, and to a lesser extent recombinant fusion proteins, do cross the placenta during the second and third trimester and are functional in the fetus, as evidence by lymphopaenia reported at birth in children exposed to rituximab in utero. In addition, live vaccines should be avoided in children with in utero exposure to biologics for at least the first 6 months of life. The longer-term effects of in utero exposure remain unknown. Studies suggest that many of these drugs do enter breast milk in small amounts, but the extent to which they are absorbed by the infant is less clear. Limited reports have not suggested adverse pregnancy outcomes in women whose partners were exposed to anti-TNF therapies or rituximab at the time of conception. Data on other biologic therapies, including anakinra, abatacept and tocilizumab, in both men and women remain extremely limited.

Serotonin: a local regulator in the mammary gland epithelium

Serotonin (5-hydroxytryptamine, 5-HT) is a very simple molecule that plays key roles in complex communication mechanisms within the animal body. In the mammary glands, serotonin biosynthesis and secretion are induced in response to dilation of the alveolar spaces. Since its discovery several years ago, mammary 5-HT has been demonstrated to perform two homeostatic functions. First, serotonin regulates lactation and initiates the transition into the earliest phases of involution. Second, serotonin is a local signal that induces parathyroid hormone-related peptide (PTHrP), which allows the mammary gland to drive the mobilization of calcium from the skeleton. These processes use different receptor types, 5-HT7 and 5-HT2, respectively. In this review, we provide synthetic perspectives on the fundamental processes of lactation homeostasis and the adaptation of calcium homeostasis for lactation. We analyze the role of the intrinsic serotonin system in the physiological regulation of the mammary glands. We also consider the importance of the mammary serotonin system in pathologies and therapies associated with lactation and breast cancer.

Human milk for preterm infants: why, what, when and how?

A mother's expressed breast milk (MEBM) is overall the best feed for her preterm baby during the neonatal period, and is associated with improved short-term and long-term outcomes. Neonatal services should commit the resources needed to optimise its use. The place of banked donor expressed breast milk (DEBM) is less clear, but it probably has a role in reducing the risk of necrotising enterocolitis and sepsis in preterm infants at particularly high risk. There is considerable variation in the composition of human milk and nutrient fortification is often needed to achieve intrauterine growth rates. Human milk can transmit potentially harmful micro-organisms, and pasteurisation, which denatures some of the bioactive factors, is the only known way of preventing this. This is carried out for DEBM but not MEBM in the UK. Future research on human milk should focus on (a) critical exposure periods, (b) understanding better its bioactive properties, (c) the role of DEBM and (d) nutritional quality assurance.

The suckling piglet as an agrimedical model for the study of pediatric nutrition and metabolism

The neonatal pig ranks among the most prominent research models for the study of pediatric nutrition and metabolism. Its precocial development at birth affords ready adaptation to artificial rearing systems, and research using this model spans a wide array of nutrients. Sophisticated in vitro and in vivo methodologies supporting both invasive, reduction-science research as well as whole-animal preclinical investigations have been developed. Potential applications may dually benefit both agricultural and medical sciences (e.g., "agrimedical research"). The broad scope of this review is to outline the fundamental elements of the piglet model and to highlight key aspects of relevance to various macronutrients, including lipids, carbohydrates, proteins/amino acids, and calcium/phosphorus. The review examines similarities between piglets and infants and also piglet idiosyncrasies, concluding that, overall, the piglet represents an adaptable and robust model for pediatric nutrition and metabolism research.

High serum leptin levels in infancy can potentially predict obesity in childhood, especially in formula-fed infants

AIM

To investigate serum leptin levels in breast-fed and formula-fed infants in infancy and their possible relationship to body mass index (BMI) in childhood.

METHODS

We enrolled 237 healthy term infants between September 2000 and April 2004 and tested their serum leptin levels, took anthropometric measurements and calculated BMI. A follow-up study was carried out to evaluate the BMI of 89 of these infants in childhood, in relation to their serum leptin levels in infancy, at a median (interquartile range) age of 8.8 years (7.8-10.2). The statistical significance of this multivariate analysis was set at p < 0.05.

RESULTS

Breast-fed infants had significantly higher serum leptin levels than formula-fed ones (p < 0.05). Children who were formula-fed in infancy had a significantly higher BMI, at follow-up, than those who were breast-fed (p < 0.001). Furthermore, we identified a leptin cut-off value of 2.7 ng/mL, below which infants had a higher BMI in childhood.

CONCLUSION

A higher leptin level in infancy may be inversely associated with BMI in childhood, suggesting that this hormone in infancy is a potential predictor of obesity in later life. Further investigation is required to be conclusive and to confirm our empirical evidence.

Nutritional support of infants with intestinal failure: something more than fishy is going on here!

BACKGROUND

This review will highlight recent advances in the care of infants with Intestinal Failure, focusing on the benefits of a multi-disciplinary team and the types of nutrition used.

METHODS

Recent best "practices" from the literature are described, including strategies for promoting intestinal adaptation, the use of lipid sparing Parenteral Nutrition (PN) and the effects of the associated high glucose infusion rates. Special emphasis will be placed on lipid minimization and specialized lipid emulsions including fish oil, and blended lipid sources such as SMOF. Enteral nutritional therapy will be reviewed, including the rationale for the use of expressed breast milk or elemental formula in preference to partial milk hydrolysates. The utility and indications for the use of formula additives and the use of nutritional supplements and the timing and rate of advancement of feeds, and the optimal strategy for preserving oral feeding skills will be reviewed. Treatments to optimize intestinal adaptation such as the use of dietary supplements including vegetable oils, fat emulsions and medium-chain triglycerides will be discussed. Feeding strategies will be described. The rationale and effects of using rotating antibiotics to treat small intestinal bacterial overgrowth will be reviewed.

RESULTS

The long-term consequences and complications of the different types of nutritional therapy will be examined, with a focus on growth and development. The potential and described effects of established and novel lipid therapies on neurological development will be reviewed in detail.

CONCLUSION

Areas of interest for potential future research will be explored for all aspects of nutritional therapy with a discussion of future strategies which may enhance the intestinal adaptive process, and thus aid our goal of making the adaptation process occur more quickly and shortening the time of PN.

Dynamics of human milk nutrient composition of women from Singapore with a special focus on lipids

BACKGROUND

A recent report suggested that human milk (HM) composition not only changes with lactation stages but also vary according to gender of the offspring. In spite of available literature, the dynamic changes of HM composition still remain to be completely explored and characterized. Progress in analytical technologies together with quantitative sampling of HM allows for a better quantification of HM nutrients and thereby providing a deeper understanding of the dynamics of HM secretion.

OBJECTIVE

To characterize and quantify HM nutrients based on appropriate for analyses sampling procedures and advanced analytical methodologies.

CLINICAL STUDY DESIGN

We conducted an observatory, single center, longitudinal trial with HM collection at 30, 60, and 120 days postpartum from 50 mothers (singleton-deliveries of 25 male and 25 female infants). HM samples were analyzed for lipid, lactose, energy density, fatty acids, phospholipids, and gangliosides. Longitudinal analyses of the datasets have been carried out using linear mixed models.

RESULTS

HM for male infants compared to females at 120 days, were higher for energy content and lipids by 24 and 39%, respectively. Similarly, other bioactive lipids such as linoleic acid, phospholipids and gangliosides were also significantly different based on the gender of the infant. Significant stage-based differences were observed for total lipids, energy density, phospholipids, and gangliosides. Such difference in HM composition may stem from different energy needs to cope up for individual growth and development.

CONCLUSION

Collectively, the current observations affirm that HM secretion, especially the lipid composition, is a very dynamic and personalized biological process.

Characterization and in vitro properties of oral lactobacilli in breastfed infants

Background

Lactobacillus species can contribute positively to general and oral health and are frequently acquired by breastfeeding in infancy. The present study aimed to identify oral lactobacilli in breast and formula-fed 4 month-old infants and to evaluate potential probiotic properties of the dominant Lactobacillus species detected. Saliva and oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining the effect of a new infant formula on child growth and development. Saliva was cultured and Lactobacillus isolates were identified from 16S rRNA gene sequences. Five L. gasseri isolates that differed in 16S rRNA sequence were tested for their ability to inhibit growth of selected oral bacteria and for adhesion to oral tissues. Oral swab samples were analyzed by qPCR for Lactobacillus gasseri.

Results

43 (32.3%) infants were breastfed and 90 (67.7%) were formula-fed with either a standard formula (43 out of 90) or formula supplemented with a milk fat globule membrane (MFGM) fraction (47 out of 90). Lactobacilli were cultured from saliva of 34.1% breastfed infants, but only in 4.7% of the standard and 9.3% of the MFGM supplemented formula-fed infants. L. gasseri was the most prevalent (88% of Lactobacillus positive infants) of six Lactobacillus species detected. L. gasseri isolates inhibited Streptococcus mutans binding to saliva-coated hydroxyapatite, and inhibited growth of S. mutans, Streptococcus sobrinus, Actinomyces naeslundii, Actinomyces oris, Candida albicans and Fusobacterium nucleatum in a concentration dependent fashion. L. gasseri isolates bound to parotid and submandibular saliva, salivary gp340 and MUC7, and purified MFGM, and adhered to epithelial cells. L. gasseri was detected by qPCR in 29.7% of the oral swabs. Breastfed infants had significantly higher mean DNA levels of L. gasseri (2.14 pg/uL) than infants fed the standard (0.363 pg/uL) or MFGM (0.697 pg/uL) formula.

Conclusions

Lactobacilli colonized the oral cavity of breastfed infants significantly more frequently than formula-fed infants. The dominant Lactobacillus was L. gasseri, which was detected at higher levels in breastfed than formula-fed infants and displayed probiotic traits in vitro.

Development of a high-throughput glycoanalysis method for the characterization of oligosaccharides in human milk utilizing multiplexed capillary gel electrophoresis with laser-induced fluorescence detection

During the last decade, enormous progress regarding knowledge about composition and properties of human milk (HM) has been made. Besides nutrition, the three macro-nutrients: proteins, lipids, and carbohydrates combine a large variety of properties and functions. Especially, complex oligosaccharides emerge as important dietary factors during early life with multiple functions. The characterization of these HM oligosaccharides (HMOS) within the total carbohydrate fraction is prerequisite to understand the relationship between milk composition and biological effects. Therefore, extended studies of large donor cohorts and thus, new high-throughput glycoanalytical methods are needed. The developed method comprises sample preparation, as well as analysis of HMOS by multiplexed CGE with LIF detection (xCGE-LIF). Via a respective database the generated "fingerprints" (normalized electropherograms) could be used for structural elucidation of HMOS. The method was tested on HM samples from five different donors, partly sampled as a series of lactation time points. HMOS could be easily identified and quantified. Consequently, secretor and Lewis status of the donors could be determined, milk typing could be performed and quantitative changes could be monitored along lactation time course. The developed xCGE-LIF based "real" high-throughput HMOS analysis method enables qualitative and quantitative high-performance profiling of the total carbohydrate fraction composition of large sets of samples.