Differences in fat content and fatty acid proportions among colostrum, transitional, and mature milk from women delivering very preterm, preterm, and term infants

Comparative lipidomics analysis of human colostrum, mature milk and yak mature milk

Yak milk is a promising lipid source substitute for infant formulas designed to mimic human milk. However, comparative studies on the lipid profiles between human and yak milk are scarce. To address this gap, in this study, we thoroughly analysed and compared the lipidome and fatty acid (FA) composition of human colostrum, human mature milk and yak mature milk. A total of 2686 lipid species from 30 lipid classes were identified in the three milk types. Notably, yak mature milk surpassed both human milk stages in the total content of lipid species, triglycerides (TG) and saturated FA. In particular, three potential lipid biomarkers, namely TG(6,0_8,0_14:0) + NH4, TG(16,0_6,0_8:0) + NH4 and TG(10,0_12,0_12,0) + NH4, were identified to differentiate yak mature milk from human colostrum and mature milk. Moreover, upon analysing the lipid metabolic pathways, it was found that the lipids involved in the pathways of acetylcholine synthesis, as well as starch and sucrose metabolism, may not manifest notable differences between yak mature milk and human colostrum, indicating the presence of similar neurodevelopment-regulating and metabolic characteristics in yak milk as in colostrum. Therefore, this comprehensive comparison offers novel insights into the potential of yak mature milk lipids to enhance the humanisation of infant formulas.

A review on lipid inclusion in preterm formula: Characteristics, nutritional support, challenges, and future perspectives

The lack of nutrient accumulation during the last trimester and the physiological immaturity at birth make nutrition for preterm infants a significant challenge. Lipids are essential for preterm infant growth, neurodevelopment, immune function, and intestinal health. However, the inclusion of novel lipids in preterm formulas has rarely been discussed. This study discusses specific lipid recommendations for preterm infants according to authoritative legislation based on their physiological characteristics. The gaps in lipid composition, such as fatty acids, triacylglycerols, and complex lipids, between preterm formulas and human milk have been summarized. The focus of this study is mainly on the vital roles of lipids in nutritional support, including long-chain polyunsaturated fatty acids, structural lipids, milk fat global membrane ingredients, and other minor components. These lipids have potential applications in preterm formulas for improving lipid absorption, regulating lipid metabolism, and protecting against intestinal inflammation. The lipidome and microbiome can be used to provide adequately powered evidence of the effects of lipids. This study proposes nutritional strategies for preterm infants and suggests approaches to enhance their lipid quality in preterm formula.

Challenges and Opportunities in Quantifying Bioactive Compounds in Human Breastmilk

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

Research progress on factors affecting the human milk metabolome

Human milk is the gold standard for infant nutrition and contains macronutrients, micronutrients, and various bioactive substances. The human milk composition and metabolite profiles are complex and dynamic, complicating its specific analysis. Metabolomics, a recently emerging technology, has been used to identify human milk metabolites classes. Applying metabolomics to study the factors affecting human milk metabolites can provide significant insights into the relationship between infant nutrition, health, and development and better meet the nutritional needs of infants during growth. Here, we systematically review the current status of human milk metabolomic research, and related methods, offering an in-depth analysis of the influencing factors and results of human milk metabolomics from a metabolic perspective to provide novel ideas to further advance human milk metabolomics.

Lipid analysis of breast milk and formula for preterm infants and the application and prospects of novel structural lipids - a comprehensive review

Preterm infants, often characterized by lower birth weights and underdeveloped physiologies, necessitate specialized nutritional care. While breast milk stands as the ideal nutritional source, offering substantial energy through its fatty acid content to support the infants' growth and developmental needs, its usage might not always be feasible. Fatty acids in breast milk are critical for the development of these infants. In scenarios where breast milk is not an option, formula feeding becomes a necessary alternative. Thus, a comprehensive understanding of the fatty acid profiles in both breast milk and formulas is crucial for addressing the distinct nutritional requirements of preterm infants. This paper aims to summarize the effects of lipid composition, structure, and positioning in breast milk and formula on the growth and development of preterm infants. Furthermore, it explores recent advancements in the use of novel structural lipids in formulas, laying the groundwork for future innovations in formula design specifically catered to the needs of preterm infants.

Changes in the Fatty Acid Profile of Lactating Women Living in Poland-A Comparison with the Fatty Acid Profile of Selected Infant Formulas

The present study examined the fatty acid content of human milk from Polish women living in the Warmia and Mazury region with regard to different lactation periods and compared it with the fatty acid content of selected infant formulas. The analysis included samples of breast milk-colostrum (n = 21), transitional milk (n = 26), and mature milk (n = 22). Fat was extracted using the Rose-Gottlieb method, and the fatty acid profile was determined by gas chromatography with a flame ionization detector (FID). The proportion of SFAs (saturated fatty acids) > MUFAs (monounsaturated fatty acids) > PUFAs (polyunsaturated fatty acids) was determined in each fraction of breast milk and infant formula. Palmitic, oleic, and linoleic acids predominated in breast milk and infant formulas. Colostrum contained lower contents of selected SFAs (caprylic, capric, lauric) and higher contents of selected MUFAs (ercucic) and PUFAs (arachidonic and docosahexaenoic) (p < 0.05) relative to transitional and mature milk. Infant formulas were distinguished from human milk in terms of their SFA (caproic, caprylic, lauric, arachidic), MUFA (oleic), and PUFA (linoleic, α-linoleic) content. It should be noted that infant formulas contained significantly lower trans fatty acid (TFA) content-more than thirty-six and more than nineteen times lower than in human milk. Furthermore, human milk contained branched-chain fatty acids (BCFAs) at 0.23-0.28%, while infant formulas contained only trace amounts of these acids. The average ratio of n-6 to n-3 fatty acids for human milk was 6.59:1 and was close to the worldwide ratio of 6.53 ± 1.72:1. Both principal component analysis (PCA) and cluster analysis (CA) indicated significant differences in the fatty acid profile relative to lactation and a different profile of infant formulas relative to breast milk.

Optimizing ARA and DHA in infant formula: A systematic review of global trends, regional disparities, and considerations for precision nutrition

In the context of precision nutrition, the addition of ARA and DHA in infant formula needs to consider more factors. This study conducted a comprehensive literature review, including 112 relevant Chinese and English articles, to summarize and analyze the global levels of ARA, DHA, and the ARA/DHA ratio in breast milk. The data were correlated with local aquatic products intake and children's IQ. The results indicated that the average level of DHA in breast milk across regions is lower than that of ARA. Variations in DHA content were identified as a primary factor influencing ARA/DHA ratio fluctuations. Breast milk ARA and DHA levels decrease with prolonged lactation periods but increase over the past 22 years. Correlation analysis revealed a significant positive relationship between aquatic products intake and breast milk DHA levels (r = 0.64, p < 0.05). Breast milk DHA levels also showed a significant positive correlation with children's IQ (r = 0.67, p < 0.01). Stable breast milk ARA content did not exhibit significant correlations with aquatic products intake or children's IQ (r = 0, p > 0.05). Among 22 infant formula products available in China, only 5 had ARA levels within the range of breast milk. Most formula products had higher ARA levels than DHA, resulting in ARA/DHA ratios generally exceeding 1. The temporal and spatial variability in breast milk ARA and DHA levels may lead to diverse health outcomes in infants. Therefore, the addition of ARA and DHA in infant formula should consider this variability, including the molecular forms and positional isomerism of the added ARA and DHA. Additionally, considering the impact of different cognitive development tests and infant's gene expression on formula assessment results, there is a need to establish a more comprehensive infant health assessment system to guide the addition of ARA and DHA in formula.

Trans isomeric fatty acids in human milk and their role in infant health and development

It is well known that long chain polyunsaturated fatty acids (LCPUFAs) play an important role in neurodevelopment in the perinatal life. The most important source of these fatty acids is the diet, however, they can also be formed in the human body from their shorter chain precursors, the essential fatty acids. Since the WHO recommends exclusive breastfeeding for the first six months after birth, the exclusive source of these fatty acids for breastfed infants is human milk, which can be influenced by the mother's diet. Unsaturated fatty acids can have either cis or trans configuration double bond in their chain with distinct physiological effects. Cis isomeric unsaturated fatty acids have several beneficial effects, while trans isomers are mostly detrimental, because of their similar structure to saturated fatty acids. Trans fatty acids (TFAs) can be further subdivided into industrial (iTFA) and ruminant-derived trans fatty acids (rTFA). However, the physiological effects of these two TFA subgroups may differ. In adults, dietary intake of iTFA has been linked to atherosclerosis, insulin resistance, obesity, chronic inflammation, and increased development of certain cancers, among other diseases. However, iTFAs can have a negative impact on health not only in adulthood but in childhood too. Results from previous studies have shown that iTFAs have a significant negative effect on LCPUFA levels in the blood of newborns and infants. In addition, iTFAs can affect the growth and development of infants, and animal studies suggest that they might even have lasting negative effects later in life. Since the only source of TFAs in the human body is the diet, the TFA content of breast milk may determine the TFA supply of breastfed infants and thus affect the levels of LCPUFAs important for neurodevelopment and the health of infants. In this review, we aim to provide an overview of the TFA content in human milk available in the literature and their potential effects on infant health and development.

The core phageome and its interrelationship with preterm human milk lipids

Phages and lipids in human milk (HM) may benefit preterm infant health by preventing gastrointestinal pathobiont overgrowth and microbiome modulation. Lipid association may promote vertical transmission of phages to the infant. Despite this, interrelationships between lipids and phages are poorly characterized in preterm HM. Shotgun metagenomics and untargeted lipidomics of phage and lipid profiles from 99 preterm HM samples reveals that phages are abundant and prevalent from the first week and throughout the first 100 days of lactation. Phage-host richness of preterm HM increases longitudinally. Core phage communities characterized by Staphylococcus- and Propionibacterium-infecting phages are significantly correlated with long-chain fatty acid abundances over lactational age. We report here a phage-lipid interaction in preterm HM, highlighting the potential importance of phage carriage in preterm HM. These results reveal possible strategies for phage carriage in HM and their importance in early-life microbiota development.

Ornidazole Transfer into Colostrum and Assessment of Exposure Risk for Breastfeeding Infant: A Population Pharmacokinetic Analysis

Ornidazole is frequently used for the prevention and treatment of anaerobic infections after caesarean section. There is still a lack of data on the excretion of ornidazole in breast milk. Therefore, the aim of this study was to investigate the transfer of ornidazole into colostrum and to assess the risk of infant exposure to the drug via breast milk. Population pharmacokinetic analysis was conducted using datasets of plasma and milk concentrations obtained from 77 breastfeeding women to examine the excretion kinetics of ornidazole. Various factors that may affect the excretion of ornidazole were investigated. The final model was then used to simulate ornidazole concentration-time profiles in both plasma and milk. The drug exposure in body fluids and the potential risk for breastfeeding were assessed based on the safety threshold. Plasma ornidazole concentration data could be described well by a one-compartment model, and concentrations in breast milk were linked to this model using an estimated milk-to-plasma concentration ratio (MPRcon). Significant variables that influenced drug exposure and MPRcon were identified as total bilirubin levels (TBIL) and postnatal sampling time, respectively. Simulations showed that women with abnormal liver function (TBIL > 17 μmol/L) had higher ornidazole levels in plasma and milk than those with normal liver function (TBIL < 17 μmol/L), but the exposures through colostrum of lactating women from both groups were below the safety threshold. This work provides a simple and feasible strategy for the prediction of drug exposure in breast milk and the assessment of breastfeeding safety.

Adverse effects of gestational ω-3 and ω-6 polyunsaturated fatty acid imbalance on the programming of fetal brain development

Obesity is a key medical challenge of our time. The increasing number of children born to overweight or obese women is alarming. During pregnancy, the circulation of the mother and her fetus interact to maintain the uninterrupted availability of essential nutrients for fetal organ development. In doing so, the mother's dietary preference determines the amount and composition of nutrients reaching the fetus. In particular, the availability of polyunsaturated fatty acids (PUFAs), chiefly their ω-3 and ω-6 subclasses, can change when pregnant women choose a specific diet. Here, we provide a succinct overview of PUFA biochemistry, including exchange routes between ω-3 and ω-6 PUFAs, the phenotypes, and probable neurodevelopmental disease associations of offspring born to mothers consuming specific PUFAs, and their mechanistic study in experimental models to typify signaling pathways, transcriptional, and epigenetic mechanisms by which PUFAs can imprint long-lasting modifications to brain structure and function. We emphasize that the ratio, rather than the amount of individual ω-3 or ω-6 PUFAs, might underpin physiologically correct cellular differentiation programs, be these for neurons or glia, during pregnancy. Thereupon, the PUFA-driven programming of the brain is contextualized for childhood obesity, metabolic, and endocrine illnesses.

Human Milk Fatty Acid Composition and Its Effect on Preterm Infants' Growth Velocity

This study aimed to analyze the fatty acid content in human milk and to find its relationship with the growth velocity of preterm infants. Mature milk samples from 15 mothers of preterm infants were collected from three different hospitals, followed by lipid extraction, fatty acid methylation, and finally gas chromatography analysis to determine the fatty acids composition. The average total lipid content was 3.61 ± 1.57 g/100 mL with the following classes of fatty acids: saturated fatty acids 43.54 ± 11.16%, unsaturated fatty acids 52.22 ± 10.89%, in which monounsaturated fatty acids were 36.52 ± 13.90%, and polyunsaturated fatty acids were 15.70 ± 7.10%. Polyunsaturated fatty acid sub-class n-6 was 15.23 ± 8.23% and n-3 was 0.46 ± 0.18%. Oleic acid, palmitic acid, and linoleic acid were the most abundant fatty acids. The n-6/n-3 ratio was 32.83:1. EPA and DHA fatty acids were not detected. As gestational age and birth weight increase, C20:2n6 content increases. The growth velocity increases with the decrement in C16 and increment in C20:2n6. The lipid profile of preterm human milk was found to be low in some essential fatty acids, which may affect the quality of preterm infants' nutrition.

Higher Availability of Long-Chain Monounsaturated Fatty Acids in Preterm than in Full-Term Human Milk

While the role of n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFAs) in the maturation of the infantile nervous system is extensively studied and relatively well-characterized, data on the potential developmental importance of the n-9 long-chain monounsaturated fatty acid (LCMUFA), nervonic acid (NA, C24:1n-9) are scarce and ambiguous. Therefore, the aim of the present study was to reanalyze our available data on the contribution of NA and its LCMUFA precursors, gondoic acid (C20:1n-9) and erucic acid (EA, C22:1n-9) to the fatty acid composition of human milk (HM) during the first month of lactation in mothers of both preterm (PT) and full-term (FT) infants. HM samples were obtained daily during the first week of lactation, and then on the 14th, 21st, and 28th days. Values of the LCMUFAs, C20:1n-9, EA, and NA were significantly higher in colostrum than in transient and mature HM. Consequently, there were highly significant inverse associations between LCMUFA values and the duration of lactation. Moreover, C20:1n-9, EA, and NA values were monotonously, considerably, and at many timepoints significantly higher in PT than in FT HM samples. By the 28th day of lactation, summarized LCMUFA values in PT HM samples declined to the level measured in FT HM samples on the first day of lactation; however, EA and NA values were still significantly higher in PT than in FT HM on the 28th day. Significantly higher availability of LCMUFAs in PT than in FT HM underpins the potential biological role of this hitherto somewhat neglected group of fatty acids.

The Impact of Linoleic Acid on Infant Health in the Absence or Presence of DHA in Infant Formulas

Both linoleic acid (LA) and α-linolenic acid (ALA) are essential dietary fatty acids, and a balanced dietary supply of these is of the utmost importance for health. In many countries across the globe, the LA level and LA/ALA ratio in breast milk (BM) are high. For infant formula (IF), the maximum LA level set by authorities (e.g., Codex or China) is 1400 mg LA/100 kcal ≈ 28% of total fatty acid (FA) ≈ 12.6% of energy. The aims of this study are: (1) to provide an overview of polyunsaturated fatty acid (PUFA) levels in BM across the world, and (2) to determine the health impact of different LA levels and LA/ALA ratios in IF by reviewing the published literature in the context of the current regulatory framework. The lipid composition of BM from mothers living in 31 different countries was determined based on a literature review. This review also includes data from infant studies (intervention/cohort) on nutritional needs regarding LA and ALA, safety, and biological effects. The impact of various LA/ALA ratios in IF on DHA status was assessed within the context of the current worldwide regulatory framework including China and the EU. Country averages of LA and ALA in BM range from 8.5-26.9% FA and 0.3-2.65% FA, respectively. The average BM LA level across the world, including mainland China, is below the maximum 28% FA, and no toxicological or long-term safety data are available on LA levels > 28% FA. Although recommended IF LA/ALA ratios range from 5:1 to 15:1, ratios closer to 5:1 seem to promote a higher endogenous synthesis of DHA. However, even those infants fed IF with more optimal LA/ALA ratios do not reach the DHA levels observed in breastfed infants, and the levels of DHA present are not sufficient to have positive effects on vision. Current evidence suggests that there is no benefit to going beyond the maximum LA level of 28% FA in IF. To achieve the DHA levels found in BM, the addition of DHA to IF is necessary, which is in line with regulations in China and the EU. Virtually all intervention studies investigating LA levels and safety were conducted in Western countries in the absence of added DHA. Therefore, well-designed intervention trials in infants across the globe are required to obtain clarity about optimal and safe levels of LA and LA/ALA ratios in IF.

Obesity-derived alterations in the lactating mammary gland: Focus on prolactin

Obesity is a modern pandemic with negative consequences in women's reproductive health. Women with overweight and obesity can develop mammary gland alterations that unable exclusive breastfeeding. Obesity associates with a disturbed lactating mammary gland endocrine environment including a decreased action of the hormone prolactin (PRL), the master regulator of lactation. The PRL receptor and the action of PRL are reduced in the mammary gland of lactating rodents fed an obesogenic diet and are contributing factors to impaired lactation in obesity. Also, treatment with PRL improves milk yield in women with lactation insufficiency. This review focuses on the impact of diet-induced obesity in the lactating mammary gland and how obesity impairs the lactogenic action of PRL. Although obesity alters lactation performance in humans and rodents, the responsible mechanisms have been mainly addressed in rodents.

Summer Buffalo Milk Produced in China: A Desirable Diet Enriched in Polyunsaturated Fatty Acids and Amino Acids

The objective of the study was to compare and reveal differences in basic chemical parameters, fatty acids, amino acids, and lipid quality indices of crossbred buffalo (swamp x river type) milk produced in summer and winter. The buffalo milk samples were collected in summer (Jul-Aug) and winter (Dec-Jan) from Hubei province, China. The samples were detected by using CombiFoss apparatus, gas chromatography, and an automated specialized amino acid analyzer. The results showed that the basic chemical parameters, fatty acid profiles, lipid quality indices, and amino acid profiles of crossbred buffalo milk differed between summer and winter. Specifically, summer buffalo milk exhibited a higher content of MUFA (monounsaturated fatty acids) and PUFA (polyunsaturated fatty acids) than winter buffalo milk. Summer buffalo milk had a lower content of major SFA (saturated fatty acids), a higher content of ω-3 and DFA (hypocholesterolemic fatty acids), a lower ω-6/ω-3 ratio, a higher value of 3 unsaturated fatty acid indices (C14, C16, C18), and a lower value of IA (index of atherogenicity) and IT (index of thrombogenicity) than winter buffalo milk. Additionally, 17 amino acids, including 8 EAA (essential amino acids) and 9 NEAA (non-essential amino acids) were higher in summer buffalo milk. These results indicated that summer buffalo milk was more health-beneficial than winter buffalo milk. Therefore, summer buffalo milk might be a desirable diet option for human nutrition and health. Our findings provide valuable information for the research and development of buffalo dairy products in China or other Asian countries.

Associations of Region and Lactation Stage with Odd-Chain Fatty Acid Profile in Triglycerides of Breast Milk in China

Odd-chain fatty acids (OCFAs), with potential value for growing infants, have been reported in breast milk. The association of location and lactation stage with the profile and content of OCFAs in breast milk was studied. We analyzed 1487 breast milk samples collected from 12 areas in China, and 102 infant formulas from different brands were purchased from the local supermarket. The content of sn-2 C15:0 significantly decreased from the colostrum to the mature stage, while that of C17:0 was not significantly increased by the lactation stage (p > 0.05). The content of C15:0 and C17:0 significantly decreased dramatically after the colostrum period, while the content of C13:0 was highest in the mature stage. The level of C15:0 and C17:0 in human milk from Gansu and Xinjiang was significantly higher than that from other areas. Similar trends were observed on the level of sn-2 C15:0 and C17:0, whereas the content of sn-2 C11:0 and C13:0 was significantly higher in breast milk from Shandong. Based on the PDS-LA analysis, the difference among infant formulas, each stage of human milk and human milk from different locations were different. Research is needed to determine if there are health benefits associated with OCFAs.

Human Milk Lipid Profiles around the World: A Systematic Review and Meta-Analysis

Reported breast milk lipid concentrations may vary with geographical region, postnatal age, and year of sample collection. In this review, we summarized data on the concentrations of total fat, total phospholipids, cholesterol, and fatty acids in human milk worldwide and their variation according to lactation stage, study area, and sample collection year. A systematic literature search was performed using the PubMed, Embase, Web of Science, and Medline databases for English-language papers and Wanfang and China National Knowledge Infrastructure databases for Chinese-language papers. A total of 186 studies evaluating the human milk lipid profiles were included. According to random-effects models based on worldwide data, the summarized means (95% CIs) as percentages of total fat were 42.2% (41.1%, 43.3%) for SFAs, 36.6% (35.6%, 37.5%) for MUFAs, and 21.0% (19.3%, 22.7%) for PUFAs. However, the study heterogeneity was high for most types of fatty acids (I2 > 99%). Human milk from Western countries had higher concentrations of MUFAs and 18:1n-9 (ω-9), but lower concentrations of PUFAs, 18:2n-6, 20:4n-6, 18:3n-3, 20:5n-3, 22:6n-3, and total n-6 PUFA compared with those from non-Western countries (P < 0.001-0.011). Significant lactation stage differences were observed for total fat and some individual fatty acids. The concentrations of SFAs and 16:0 were significantly negatively correlated with sampling year (P < 0.001-0.028). In contrast, a significant positive correlation between the concentrations of 18:2n-6 and 18:3n-3 and sampling year was observed (P < 0.001-0.035). Our results suggest that the pooling of data on human milk lipid profiles in different studies should be done with caution due to the high between-study heterogeneity. The concentration of lipids, including total fat, cholesterol, and specific fatty acids, differs in human milk according to lactation stage, geographical region, and year of sample collection.

Exploring the Potential of Human Milk and Formula Milk on Infants’ Gut and Health

Early-life gut microbiota plays a role in determining the health and risk of developing diseases in later life. Various perinatal factors have been shown to contribute to the development and establishment of infant gut microbiota. One of the important factors influencing the infant gut microbial colonization and composition is the mode of infant feeding. While infant formula milk has been designed to resemble human milk as much as possible, the gut microbiome of infants who receive formula milk differs from that of infants who are fed human milk. A diverse microbial population in human milk and the microbes seed the infant gut microbiome. Human milk contains nutritional components that promote infant growth and bioactive components, such as human milk oligosaccharides, lactoferrin, and immunoglobulins, which contribute to immunological development. In an attempt to encourage the formation of a healthy gut microbiome comparable to that of a breastfed infant, manufacturers often supplement infant formula with prebiotics or probiotics, which are known to have a bifidogenic effect and can modulate the immune system. This review aims to elucidate the roles of human milk and formula milk on infants’ gut and health.

Content of industrially produced trans fatty acids in breast milk: An observational study

Breast milk may contain industrially produced trans fatty acids (TFAs), which can affect the content of essential fatty acids (EFAs). This could have significant implications for the child's development. The fatty acids present in breast milk can be modified by adjusting the mother's diet. The objective of this study was to determine the content of industrially produced TFAs present in colostrum, transitional milk, and mature milk produced by mothers between 18 and 45 years of age in the state of Querétaro, Mexico, based on a longitudinal observational study. The TFA content in the breast milk of 33 lactating women was analyzed using gas chromatography. The mothers' consumption of TFAs was also estimated by analyzing a log prepared through 24-hr dietary recall (24HR) obtained in each period. The TFA content in the mothers' diet was similar across the colostrum, transitional milk, and mature milk phases: 1.64 ± 1.25 g, 1.39 ± 1.01, and 1.66 ± 1.13 g, respectively. The total TFA content was 1.529% ± 1.648% for colostrum; 0.748% ± 1.033% for transitional milk and 0.945% ± 1.368% for mature milk. Elaidic acid was the TFA in the highest concentration in all three types of milk. No correlation was found between the content of industrially produced TFAs in breast milk and the anthropometric measurements of the mother or between the estimated consumption of TFAs and the content of TFAs in breast milk. Elaidic acid and total content of TFAs were negatively correlated (p < .05) with the content of docosahexaenoic acid (DHA) (0.394 ± 0.247) (R = -0.382) in colostrum. The concentration of TFAs was found to correlate with the composition of EFAs in milk.

Role Medium-Chain Fatty Acids in the Lipid Metabolism of Infants

Human breastmilk, the ideal food for healthy infants, naturally contains a high concentration of medium-chain fatty acids (MCFAs, about 15% of total fatty acids). MCFAs are an important energy source for infants due to their unique digestive and metabolic properties. MCFA-enriched oils are widely used in an infant formula, especially the formula produced for preterm infants. Recently, there has been a growing interest in the triglyceride structure of MCFAs in human milk, their metabolism, and their effects on infant health. This study summarized the MCFA composition and structure in both human milk and infant formula. Recent studies on the nutritional effects of MCFAs on infant gut microbiota have been reviewed. Special attention was given to the MCFAs digestion and metabolism in the infants. This paper aims to provide insights into the optimization of formulations to fulfill infant nutritional requirements.

Fatty acid profile characterization in colostrum, transition milk, and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 38% and 19% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 72% higher in PP cows throughout the milking period, as well as 13% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 25% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 29% higher in colostrum than mature milk and 33% higher in MP cows. Linoleic acid was also 15% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 2.7-fold higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 40% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.

Polyunsaturated Fatty Acid Composition in Breast Milk Plasma of HIV-infected and Uninfected Mothers in Relation to Infant Clinical Outcomes

Background:

The increased coverage of prevention of mother to child transmission (PMTCT) services has significantly reduced paediatric HIV infection incidence. The aim of the study was to compare breast milk omega-6 and omega-3 polyunsaturated fatty acid profiles of HIV infected and uninfected mothers and determine the association between fatty acid profiles and postnatal transmission of HIV, morbidity/mortality of HIV exposed and unexposed infants.

Methods:

A prospective cohort study of 57 HIV infected and 57 HIV uninfected lactating mothers was conducted in Gweru, Zimbabwe from July 2019 to March 2020. The women’s 114 babies (term and preterm) were also enrolled and stratified by HIV exposure and infection status. The mother-infant pairs were followed up at 6 weeks, 16 weeks and 6 months postpartum to determine, HIV transmission rate, breast milk polyunsaturated fatty acid profiles as well as infant clinical outcomes.

Results:

The mean breast milk docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels in HIV uninfected mothers (0.82 ± 0.92; 0.47 ± 0.75 μg/ml respectively) at 6 weeks postpartum were significantly higher compared to those of HIV infected mothers (0.33 ± 0.32; 0.08 ± 0.14 μg/ml) respectively. The same pattern was observed at 16 weeks postpartum in terms of DHA and EPA mean concentration. However, the arachidonic acid (AA) levels and AA/DHA ratio measured at 6 weeks postpartum were significantly higher in HIV infected mothers (2.31 ± 2.01; 17.18 ± 52.47 respectively) compared to HIV uninfected mothers (0.82 ± 0.54; 9.71 ± 21.80; P < .001). A higher morbidity rate was observed amongst HIV exposed infants than HIV unexposed infants (3.26 ± 0.13; 2.49 ± 0.09; P < .001) respectively. A significant positive correlation was observed between AA and infant morbidity (r = .388; P < .001).

Conclusion:

Deficiencies in breast milk omega-3 fatty acids were observed in HIV infected women. Maintaining a healthy balance between omega-6 and omega-3 fatty acid diets is critical for breast feeding mothers regardless of their HIV status. The adverse clinical outcomes observed amongst HIV exposed infants emphasise their vulnerability under conditions of maternal universal antiretroviral therapy.

Preparation of Human Milk Fat Substitutes: A Review

Human milk is generally regarded as the best choice for infant feeding. Human milk fat (HMF) is one of the most complex natural lipids, with a unique fatty acid composition and distribution and complex lipid composition. Lipid intake in infants not only affects their energy intake but also affects their metabolic mode and overall development. Infant formula is the best substitute for human milk when breastfeeding is not possible. As the main energy source in infant formula, human milk fat substitutes (HMFSs) should have a composition similar to that of HMF in order to meet the nutritional needs of infant growth and development. At present, HMFS preparation mainly focuses on the simulation of fatty acid composition, the application of structured lipids and the addition of milk fat globule membrane (MFGM) supplements. This paper first reviews the composition and structure of HMF, and then the preparation development of structured lipids and MFGM supplements are summarized. Additionally, the evaluation and regulation of HMFSs in infant formula are also presented.

Fatty acid profile characterization in colostrum, transition milk, and mature milk of primi- and multiparous cows during the first week of lactation

The specific fatty acid (FA) profile of colostrum may indicate a biological requirement for neonatal calves. The objective of this study was to characterize the FA profile and yields in colostrum, transition milk, and mature milk in primiparous (PP) and multiparous (MP) cows. Colostrum was milked from 10 PP and 10 MP Holstein cows fed the same pre- and postpartum rations. Milkings (M) 2 to 5 and 12 were respectively termed transition and mature milk. Overall, short-chain FA (C4:0 and C6:0) were 61 and 50% lower in colostrum than mature milk, respectively. A parity by milking interaction was also present, with higher C4:0 for PP cows at M2 and for MP cows at M12. Additionally, higher concentrations of C6:0 were present for PP cows at M2 through M4 and for MP cows at M12. Palmitic (C16:0) and myristic (C14:0) acids were 16% and 27% higher in colostrum than mature milk, respectively. However, total saturated FA remained relatively stable. Branched-chain FA were 13% lower in colostrum than mature milk and higher in PP than MP cows throughout the milking period. The proportion of trans-monounsaturated FA (MUFA) was 42% higher in PP cows throughout the milking period, as well as 15% lower in colostrum than mature milk. In contrast, cis-MUFA and total MUFA were not affected by milking nor parity. Linoleic acid (LA) was 13% higher in colostrum than transition and mature milks, but α-linolenic acid (ALA) did not differ. Consequently, the ratio of LA to ALA was 23% higher in colostrum than mature milk and 25% higher in MP cows. Linoleic acid was also 13% higher in MP cows, whereas ALA was 15% higher in PP cows. Conjugated linoleic acid (CLA, cis-9,trans-11) was 63% higher in PP cows, and no differences between colostrum and mature milk were detected. Overall, polyunsaturated FA (PUFA) from the n-6 and n-3 series were over 25% higher in colostrum compared with transition and mature milk. Milking by parity interactions were present for arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), and total n-3 PUFA, translating to higher proportions in PP cows in M1 to M3, whereas proportions remained relatively stable throughout the milking period in MP cows. Despite increasing milk yields throughout the subsequent milkings, higher yields of EPA, ARA, DPA, and DHA were present in colostrum than in mature milk. Greater proportions and yields of n-3 and n-6 FA in colostrum may translate to specific requirements for newborn calves. Differences were also observed between PP and MP cows and may reflect different nutrient requirements and partitioning.

Total and Sn-2 Fatty Acid Profile in Human Colostrum and Mature Breast Milk of Women Living in Inland and Coastal Areas of China

INTRODUCTION

Although lipid is the major energy source and exerts beneficial effects on infant growth, research on the composition of fatty acid (FA) at the sn-2 position of human milk (HM) in China and abroad is limited.

OBJECTIVES

This study aimed to investigate the FA positional distribution in colostrum and mature HM of women living in the inland and coastal areas of China and explore the potential influences of geographical region and lactation stage on the FA profile of Chinese women.

METHODS

Colostrum milk (n = 61) and mature milk (n = 56) samples were obtained longitudinally from healthy lactating women in Guangzhou and Chengdu, China. Gas chromatography was used to determine the total and sn-2 FA composition.

RESULTS

Significant differences were observed in the FA profile of HM between different regions and lactation stages, with differences in polyunsaturated FA levels being the most pronounced. Nearly 70% of sn-2 FAs were saturated FAs, of which C16:0 accounted for approximately 75%. C8:0, C10:0, C18:0, C20:0, C22:0, and all of the unsaturated FAs were mainly located at the sn-1 and sn-3 positions, while C14:0, C15:0, and C16:0 were mainly at the sn-2 position. The proportion of C12:0 and C17:0 at sn-2 was approximately equivalent to that at the sn-1, 3 positions.

CONCLUSIONS

The results indicate the variability in the FA profile of HM between regions and lactation stages. The contents of polyunsaturated FAs and sn-2 FAs, especially palmitic acid, should be paid more attention when optimizing infant formula.

Efficacy of Docosahexaenoic Acid for the Prevention of Necrotizing Enterocolitis in Preterm Infants: A Randomized Clinical Trial

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease and a leading cause of morbidity and mortality in preterm infants. In this study, a randomized double-blind parallel-group (1:1) trial was carried out in two neonatal intensive care units of two tertiary hospitals. Two hundred and twenty-five preterm newborns with an expected functional gastrointestinal tract were recruited and received an enteral dose of 75 mg of docosahexaenoic acid (DHA)/kg body weight or high-oleic sunflower oil daily for 14 days from the first enteral feed after birth. Confirmed NEC was evaluated with Bell’s scale from stage ≥ IIa. Two hundred and fourteen randomized infants were analyzed in terms of the intent-to-treat (DHA-group: n = 105; control-group: n = 109); data for two hundred infants were analysed per protocol. Confirmed NEC was lower in infants from the DHA-group compared with the control-group (0/100 vs. 7/100; p = 0.007), with RR = 0.93 (95% CI 0.881 to 0.981), risk difference = −7%, (95% CI −12.00 to −1.99), and number needed-to-treat = 15 (95% CI 8.3 to 50). Intent-to-treat analysis showed a lower level of treatment failure in the DHA-group compared with the control-group (6/105 (6%) vs. 16/109 (15%); p = 0.03, RR = 0.905, (95% CI 0.826 to 0.991)). The results after multivariate-regression analysis remained significant. Adverse events (apart from the incidence of NEC) were not different between groups. A daily dose of DHA for 14 days starting with the first enteral feed may prevent NEC in preterm infants.

A comprehensive review on non-clinical methods to study transfer of medication into breast milk - A contribution from the ConcePTION project

Breastfeeding plays a major role in the health and wellbeing of mother and infant. However, information on the safety of maternal medication during breastfeeding is lacking for most medications. This leads to discontinuation of either breastfeeding or maternal therapy, although many medications are likely to be safe. Since human lactation studies are costly and challenging, validated non-clinical methods would offer an attractive alternative. This review gives an extensive overview of the non-clinical methods (in vitro, in vivo and in silico) to study the transfer of maternal medication into the human breast milk, and subsequent neonatal systemic exposure. Several in vitro models are available, but model characterization, including quantitative medication transport data across the in vitro blood-milk barrier, remains rather limited. Furthermore, animal in vivo models have been used successfully in the past. However, these models don't always mimic human physiology due to species-specific differences. Several efforts have been made to predict medication transfer into the milk based on physicochemical characteristics. However, the role of transporter proteins and several physiological factors (e.g., variable milk lipid content) are not accounted for by these methods. Physiologically-based pharmacokinetic (PBPK) modelling offers a mechanism-oriented strategy with bio-relevance. Recently, lactation PBPK models have been reported for some medications, showing at least the feasibility and value of PBPK modelling to predict transfer of medication into the human milk. However, reliable data as input for PBPK models is often missing. The iterative development of in vitro, animal in vivo and PBPK modelling methods seems to be a promising approach. Human in vitro models will deliver essential data on the transepithelial transport of medication, whereas the combination of animal in vitro and in vivo methods will deliver information to establish accurate in vitro/in vivo extrapolation (IVIVE) algorithms and mechanistic insights. Such a non-clinical platform will be developed and thoroughly evaluated by the Innovative Medicines Initiative ConcePTION.

Short-chain fatty acid (SCFA) and medium-chain fatty acid (MCFA) concentrations in human milk consumed by infants born at different gestational ages and the variations in concentration during lactation stages

This study aimed to quantify the short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) in human milk triacylglycerols (TAGs) and investigate their concentrations in human milk consumed during lactation by infants born at different gestational ages. One hundred and eighty milk samples from the mothers of 30 full-term, 10 early-preterm (≤32 weeks), 10 mild-preterm (32-34 weeks), and 10 near-term (34-37 weeks) infants were collected from the colostrum, transitional, and mature milk. The human milk TAGs were transferred into fatty-acid methyl esters via potassium methoxide in methanol and determined using gas chromatography (GC). The total SCFA (4:0) and MCFA concentrations (6:0 and 8:0) were highest in the mature milk (1.47 ± 0.66 mg g-1 fat from full-term infant milk), approximately 42.18% higher than those in transitional milk. Significantly higher SCFA and MCFA concentrations were found in full-term milk than in preterm milk (p = 0.001). The milk TAGs were analyzed using ultra-high-performance supercritical fluid chromatography with quadrupole-time-of-flight mass spectrometry (UHPSFC-Q-TOF-MS), which showed that the SCFAs and MCFAs were mainly esterified with long-chain fatty-acid groups (16:0, 18:1 n-9, and 18:2 n-6) at the glycerol backbone. The infants' daily SCFA intake from human milk was estimated; this was highest from mature milk for full-term infants (∼14 mg d-1) which was significantly different from that of preterm infants from colostrum and transitional milk (p < 0.001). The correlation between dietary SCFAs and MCFAs in human milk and nutrition in newborns, especially in the gut microbiotas of preterm infants, requires further study.

A Systematic Review of Collection and Analysis of Human Milk for Macronutrient Composition

BACKGROUND

As human milk (HM) composition varies by time and across even a single feed, methods of sample collection can significantly affect the results of compositional analyses and complicate comparisons between studies.

OBJECTIVE

The aim was to compare the results obtained for HM macronutrient composition between studies utilizing different sampling methodologies. The results will be used as a basis to identify the most reliable HM sampling approach.

METHODS

EMBASE, MEDLINE/PubMed, Cochrane Library, Scopus, Web of Science, and ProQuest databases were searched for relevant articles. Observational and interventional studies were included, and at least 2 authors screened studies and undertook data extraction. Quality assessment was conducted using the Newcastle-Ottawa scale and previously published pragmatic score.

RESULTS

A total of 5301 publications were identified from our search, of which 101 studies were included (n = 5049 breastfeeding women). Methods used for HM collection were divided into 3 categories: collection of milk from all feeds over 24 h (32 studies, n = 1309 participants), collection at one time point (62 studies, n = 3432 participants), and "other methods" (7 studies, n = 308 participants). Fat and protein concentrations varied between collection methods within lactation stage, but there were no obvious differences in lactose concentrations. There was substantial variability between studies in other factors potentially impacting HM composition, including stage of lactation, gestational age, and analytical method, which complicated direct comparison of methods.

CONCLUSIONS

This review describes the first systematic evaluation of sampling methodologies used in studies reporting HM composition and highlights the wide range of collection methods applied in the field. This information provides an important basis for developing recommendations for best practices for HM collection for compositional analysis, which will ultimately allow combination of information from different studies and thus strengthen the body of evidence relating to contemporary HM composition. This trial was registered at PROSPERO as CRD42017072563, https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42017072563.

Human milk fatty acid profile across lactational stages after term and preterm delivery: A pooled data analysis

BACKGROUND

Lipids in human milk (HM) provide the majority of energy for developing infants, as well as crucial essential fatty acids (FA). The FA composition of HM is highly variable and influenced by multiple factors. We sought to increase understanding of the variation in HMFA profiles and their development over the course of lactation, and after term and preterm delivery, using a pooled data analysis.

OBJECTIVE

To review the literature and perform a pooled data analysis to qualitatively describe an extensive FA profile (36 FAs) in term and preterm colostrum, transitional - and mature milk up to 60 days postpartum.

DESIGN

A Medline search was conducted for HMFA profile data following term or preterm delivery. The search was confined to English language papers published between January 1980 and August 2018. Studies reporting original data, extensive FA profiles in HM from healthy mothers were included. Weighted least squares (WLS) means were calculated from the pooled data using random or fixed effect models.

RESULTS

Our pooled data analysis included data from 55 studies worldwide, for a total of 4374 term milk samples and 1017 preterm milk samples, providing WLS means for 36 FAs. Patterns in both term and preterm milk were apparent throughout lactation for some FAs: The most abundant FAs (palmitic, linoleic and oleic acid) remained stable over time, whereas several long-chain polyunsaturated FAs (including ARA and DHA) seemed to decrease and short- and medium-chain FAs increased over time.

CONCLUSIONS

High heterogeneity between individual studies was observed for the reported levels of some FAs, whereas other FAs were remarkably consistent between studies. Our pooled data suggests that specific FA categories fluctuate according to distinct patterns over the course of lactation; many of these patterns are comparable between term and preterm milk.

Fatty acids of human milk - a review

The composition of human milk is the result of the evolution of mammals over millions of years. Among the most important components of milk are fatty acids. Approximately 85% are saturated and monounsaturated fatty acids - the rest are polyunsaturated one. Their role is to provide energy and immunity and to serve as buildings blocks, as well as assisting the hormonal system and the metabolism of fats, carbohydrates and proteins. The structural differences between fatty acids determine their biodiversity and give them particular physiological importance. Correct development of the nervous system, retina and other structures depend on an adequate supply of both these fatty acids during intrauterine development and in the newborn and infant stages. The fats present in milk form milk fat globules - structures that do not appear in milk formula prepared using vegetable oils. Apart from the mother's diet, other sources of fatty acids are endogenous biosynthesis in the mammary gland and the fat deposits from which the fatty acids are released. Evolution of the mother's body has also created adaptive mechanisms that adjust the amount of fatty acids in milk to the state of health and needs of the child. These mechanisms go some way to creating a buffer with regard to dietary shortages experienced by pregnant/breastfeeding women, and optimalise the composition of milk fatty acids depending on the age of the pregnant woman, the birth weight of the infant and the efficiency of the placenta during pregnancy.

Feasibility of Standardized Human Milk Collection in Neonatal Care Units

Research in human lactation is a growing field. However, difficulties in studying human milk originate from the dynamicity of its composition. Using standardized collection protocols is mandatory to minimize variation and warrant comparability of findings across different studies. Yet, information on the feasibility of collecting human milk with standardized procedures, especially in neonatal units, are lacking. The present study aims to report on the feasibility and difficulties to collect human milk according to a standardized protocol, during early lactation from women who gave birth to preterm infants. Human milk was collected from 129 mothers of moderate- to late-preterm infants according to two variations of a standard protocol which differed for number of collection time-points. Collection rates and adherence to the sampling protocol were evaluated together with reason for missed collection. Collection of ≥1 sample was successful for 80% of the mothers. However adherence to the standard protocol was overall low (36% and 27%). Collection rates were different between the two protocol variations (73% against 92%, p ≤ 0.001). Amongst the reason for missed collection, low milk supply was the most recurrent (40%). Our findings show that while collecting human milk in neonatal units is achievable, obtaining standard and comparable samples results challenging.

The Effect of Maternal Obesity on Breast Milk Fatty Acids and Its Association with Infant Growth and Cognition-The PREOBE Follow-Up

This study analyzed how maternal obesity affected fatty acids (FAs) in breast milk and their association with infant growth and cognition to raise awareness about the programming effect of maternal health and to promote a healthy prenatal weight. Mother–child pairs (n = 78) were grouped per maternal pre-pregnancy body mass index (BMI): normal-weight (BMI = 18.5–24.99), overweight (BMI = 25–29.99) and obese (BMI > 30). Colostrum and mature milk FAs were determined. Infant anthropometry at 6, 18 and 36 months of age and cognition at 18 were analyzed. Mature milk exhibited lower arachidonic acid (AA) and docosahexaenoic acid (DHA), among others, than colostrum. Breast milk of non-normal weight mothers presented increased saturated FAs and n6:n3 ratio and decreased α-linolenic acid (ALA), DHA and monounsaturated FAs. Infant BMI-for-age at 6 months of age was inversely associated with colostrum n6 (e.g., AA) and n3 (e.g., DHA) FAs and positively associated with n6:n3 ratio. Depending on the maternal weight, infant cognition was positively influenced by breast milk linoleic acid, n6 PUFAs, ALA, DHA and n3 LC-PUFAs, and negatively affected by n6:n3 ratio. In conclusion, this study shows that maternal pre-pregnancy BMI can influence breast milk FAs and infant growth and cognition, endorsing the importance of a healthy weight in future generations.

Rapid profiling of triglycerides in human breast milk using liquid extraction surface analysis Fourier transform mass spectrometry reveals new very long chain fatty acids and differences within individuals

RATIONALE

We describe a novel method for preparing milk samples and profiling their triglyceride (TG) fractions. This method was used to explore how the TG profile of milk modulates as lactation progresses and how the TG profile differs between breasts.

METHODS

Fresh milk was spotted onto Whatman filter paper and air-dried. Liquid Extraction Surface Analysis coupled to Fourier Transform Mass Spectrometry (LESA-MS) was adapted for molecular profiling. Collision-Induced Dissociation (CID) was used to profile fatty acid residues.

RESULTS

LESA-MS produced the relative abundances of all isobaric TGs described and showed that mammary glands within one individual can produce a different profile of TGs. CID was used to uncover the configuration of isobaric triglycerides, indicating the relative amounts of the fatty acids contributing to that triglyceride's mass. This also indicated the presence of very long chain fatty acids (C26:0 and C26:1) that have not been reported before in human breast milk.

CONCLUSIONS

We conclude that spotting on paper and the use of LESA-MS and CID on milk spots is not only a means for analysing milk in unprecedented detail for this preparation time, but is also amenable to conditions in which collecting and storing fresh milk samples for detailed profiling is prohibitively difficult.

Optical properties of human milk

With human milk being the most important source of infant nutrition, the protection and support of breastfeeding are essential from a global health perspective. Nevertheless, relatively few objective methods are available to investigate human milk composition and lactation physiology when a mother experiences breastfeeding problems. We argue that optics and photonics offer promising opportunities for this purpose. Any research activity within this new application field starts with a thorough understanding on how light interacts with human milk. Therefore, the aim of this study was to investigate the full set of optical properties for human milk and the biological variability therein. Using a novel approach that combines spatially resolved diffuse reflectance spectroscopy (SR-DRS) and spectroscopic optical coherence tomography (sOCT) between 450 and 650 nm, we quantified the absorption coefficient µa , scattering coefficient µs , reduced scattering coefficient µs', anisotropy g and backscattering coefficient µb,NA of mature human milk from 14 participants released at different stages during a breastfeed (foremilk, bulk milk and hindmilk). Significant correlations were found between µa , µs , µs' and µb,NA and the biochemically determined fat concentration per sample (Rs = 0.38, Rs = 0.77, Rs = 0.80, Rs = 0.44 respectively). We explained the observed variations in the optical properties of human milk using Mie theory and the biological variability in both the concentration and size distribution of milk fat globules. In conclusion, we have provided a full set of optical properties for human milk, which can hopefully serve as a starting point for future biophotonic studies on human milk and the milk containing lactating breast.

Temporal Progression of Fatty Acids in Preterm and Term Human Milk of Mothers from Switzerland

We longitudinally compared fatty acids (FA) from human milk (HM) of mothers delivering term and preterm infants. HM was collected for 4 months postpartum at 12 time points for preterm and for 2 months postpartum at 8 time points for term group. Samples were collected from the first feed of the morning, and single breast was fully expressed. FA were analyzed by gas chromatography coupled with flame ionization detector. Oleic, palmitic and linoleic acids were the most abundant FA across lactation and in both groups. Preterm colostrum contained significantly (p < 0.05) higher 8:0, 10:0, 12:0, sum medium chain fatty acids (MCFA), 18:3 n-3 FA compared to term counterparts. Preterm mature milk contained significantly higher 12:0, 14:0, 18:2 n-6, sum saturated fatty acids (SFA), and sum MCFA. We did not observe any significant differences between the preterm and term groups for docosahexaenoic acid, arachidonic acid and eicosapentaenoic acid at any stage of lactation. Overall, preterm milk was higher for SFA with a major contribution from MCFA and higher in 18:2 n-6. These observational differences needs to be studied further for their implications on preterm developmental outcomes and on fortification strategies of either mothers’ own milk or donor human milk.

Total and sn-2 fatty acid profile of breast milk from women delivering preterm infants under the influence of maternal characteristics

Data on the total fatty acid (FA) profile and position-specific triacylglycerides (TAGs) in preterm infants' maternal milk are essential for establishing the recommended requirement of FA in preterm infants in China. We aimed to determine the composition and positional distribution of FAs in preterm infants' maternal milk in China and further investigate the effect of maternal background on the FA composition. Breast milk samples (4, 11, 30, 60, and 90 (all ±3) days post-partum) were collected from 59 healthy women delivering preterm infants. The total and sn-2 milk FA composition was determined using gas chromatography. The multivariate statistical analysis showed significant differences in the FA profiles of milk with different lactation times, gestational ages and maternal ages. In particular, the content of linoleic and linolenic acid (ALA) was much higher, whereas the content of docosahexaenoic (DHA) and arachidonic acid were lower in the preterm milk from the Wuxi district than that from America and countries in Europe. The content of sn-2 polyunsaturated FAs (ALA: p = 0.013 and DHA: p = 0.003) were lower in the preterm colostrum from women aged over 30 years. Overall, these results suggest that the European and American standards of preterm formula may not be suitable for Chinese preterm infants, and polyunsaturated FA fortification in the maternal diet or preterm formula is needed for women with advanced age.

Effect of Different Tube Feeding Methods on the Delivery of Docosahexaenoic and Arachidonic Acid: An In Vitro Pilot Study

BACKGROUND

Arachidonic acid (AA) and docosahexaenoic acid (DHA) are crucial for neural and visual development after premature birth. Preterm infants usually require tube feeding (TF) until the achievement of adequate oral feeding skills; the impact of TF on DHA and AA delivery has not been investigated yet. This study aimed to evaluate the effect of different TF techniques on the delivery of AA and DHA contained in human milk (HM).

METHODS

HM samples (65 mL each) were collected and divided into three 20-mL aliquots. The remaining 5 mL served as baseline. Three TF techniques were simulated (1 for each aliquot): gravity bolus feeding (BF), 3-hour continuous feeding using a horizontal feeding pump, and 3-hour continuous feeding with the feeding pump angled at 45°. For horizontal continuous feeding (HCF) and 45° angled continuous feeding (ACF), aliquots delivered between 0 and 90 minutes (T1) and 91 and 180 minutes (T2) were collected separately. AA and DHA concentration was analyzed by gas chromatography/mass spectrometry and compared among the TF methods. DHA and AA delivery at T1 and T2 was also evaluated.

RESULTS

Fifty-one simulated feeds were performed. DHA and AA amounts after BF and ACF did not differ significantly compared with baseline, whereas HCF resulted in significantly lower DHA and AA concentration. During T2, ACF delivered almost twice the DHA and AA amounts compared with T1.

CONCLUSION

The delivery of HM AA and DHA is significantly affected by TF, with potential clinical implications. When BF is not tolerated, ACF might represent a feasible alternative to reduce TF-related DHA and AA loss.

The validation of biomarkers of metabolic efficacy in infant nutrition

Breastfeeding is regarded as the ideal way to nourish infants. However, feeding with formula milk is also common in much of the West. Despite this, the function of the molecular components of breast and formula milks are not fully understood, less still the relationship between the composition of the milk and the infant's metabolism and how this influences the infant's development. The Biotechnology and Biological Sciences Research Council-funded project 'The validation of biomarkers of metabolic efficacy in infant nutrition' aims to identify lipid biomarkers that can be used to study the effect of diet on growth and development of infants. In this work, we have been able to validate these markers. Here, we present an approach to biomarker discovery that has new depth and will inform research questions about how metabolism is governed, and which species can be used to identify situations where metabolism is becoming defective.

Increased docosahexaenoic acid and n-3 polyunsaturated fatty acids in milk from mothers of small for gestational age preterm infants

The study aimed to test whether or not milk fatty acid composition in mothers of small for gestational age (SGA) infants is similar to that in mothers of adequate for gestational age (AGA) infants. Thirty three mothers of SGA preterm infants and 66 mothers of AGA preterm infants were included. Milk and plasma fatty acids were analyzed using capillary gas chromatography. Milk DHA (0.68 ± 0.37 vs. 0.44 ± 0.24; p < 0.01) was higher and n-6:n-3 PUFA ratio (12.0 ± 4.64 vs. 16.0 ± 6.32; p < 0.05) was lower in mothers of SGA infants. Plasma ARA and DHA were increased in mothers of SGA infants and decreased in their infants. Milk ARA or DHA was positively related to the correspondent fatty acid in plasma (r = 0.374, p = 0.010 for ARA and r = 0.690, p < 0.001 for DHA). Breast milk in mothers of preterm infants born SGA is enriched in DHA and n-3 PUFA. Breastfeeding SGA preterm infant with own mother's milk is recommended.

Long-chain polyunsaturated fatty acids decline rapidly in milk from mothers delivering extremely preterm indicating the need for supplementation

AIM

Our aim was to perform an in-depth analysis of the composition of fatty acids in milk from mothers delivering extremely preterm babies. We investigated longitudinal changes in milk fatty acid profiles and the relationship between several types of fatty acids, including omega-3 and omega-6.

METHODS

Milk samples were collected at three stages of lactation from 78 mothers who delivered at less than 28 weeks of pregnancy at the Sahlgrenska University Hospital, Gothenburg, Sweden, from April 2013 to September 2015. Fatty acid composition was analysed by gas chromatography-mass spectrometry.

RESULTS

A reduction in long-chain polyunsaturated fatty acids (LCPUFAs) was observed during the lactation period. The concentrations of arachidonic acid and docosahexaenoic acid declined from medians of 0.34 to 0.22 mol% and 0.29 to 0.15 mol%, respectively, between postnatal day 7 and a postmenstrual age of 40 weeks. Strong correlations were found between the intermediates of several classes of fatty acids, including omega-3, omega-6 and omega-9.

CONCLUSION

A rapid reduction in LCPUFA content in the mother's milk during the lactation period emphasises the importance of fatty acid supplementation to infants born extremely preterm, at least during the period corresponding to the third trimester, when rapid development of the brain and adipose tissue requires high levels of LCPUFAs.

The impact of human breast milk components on the infant metabolism

BACKGROUND & AIMS

Breastfeeding is beneficial for mothers and infants. Underlying mechanisms and biochemical mediators thus need to be investigated to develop and support improved infant nutrition practices promoting the child health. We analysed the relation between maternal breast milk composition and infant metabolism.

METHODS

196 pairs of mothers and infants from a European research project (PreventCD) were studied. Maternal milk samples collected at month 1 and month 4 after birth were analysed for macronutrient classes, hormone, and fatty acid (FA) content. Phospholipids, acylcarnitines, and amino acids were measured in serum samples of 4-month old infants. Associations between milk components and infant metabolites were analysed with spearman correlation and linear mixed effect models (LME). P-values were corrected for multiple testing (PLME).

RESULTS

Month 1 milk protein content was strongly associated with infant serum lyso-phosphatidylcholine (LPC) 14:0 (PLME = 0.009). Month 1 milk insulin was associated to infant acetylcarnitine (PLME = 0.01). There were no associations between milk protein content and serum amino acids and milk total fat content and serum polar lipids. Middle- and odd-chain FA% in breast milk at both ages were significantly related to serum LPC and sphingomyelins (SM) species in infant serum (all PLME<0.05), while FA% 20:5n-3 and 22:6n-3 percentages were significantly associated to serum LPC 22:6 (PLME = 1.91×10-4/7.93×10-5) in milk only at month 4. Other polyunsaturated fatty acids and hormones in milk showed only weak associations with infant serum metabolites.

CONCLUSIONS

Infant serum LPC are influenced by breast milk FA composition and, intriguingly, milk protein content in early but not late lactation. LPC 14:0, previously found positively associated with obesity risk, was the serum metabolite which was the most strongly associated to milk protein content. Thus, LPC 14:0 might be a key metabolite not only reflecting milk protein intake in infants, but also relating high protein content in milk or infant formula to childhood obesity risk.