Phospholipids in Human Milk and Infant Formulas: Benefits and Needs for Correct Infant Nutrition

Application of Comparative Lipidomics to Elucidate Postprandial Metabolic Excursions Following Dairy Milk Ingestion in Individuals with Prediabetes

Nutrient-dense dairy foods are an important component of a healthy diet. Recommendations, however, advise non- and low-fat dairy foods despite controversy concerning whether full-fat dairy foods adversely impact cardiometabolic health. Therefore, in this study, our objective is to examine the differential plasma lipidomic responses to non-fat or full-fat milk ingestion during postprandial hyperglycemia. Seven adults with prediabetes completed a randomized cross-over study in which glucose was consumed alone or with non-fat or full-fat dairy milk. Plasma samples collected at 90 min and 180 min post milk ingestion were used to perform untargeted lipidomics analysis. A total of 332 lipids from 20 classes and five lipid categories were detected at different time points during the postprandial period. Dairy milk, especially non-fat milk, protected against lipid changes otherwise induced by glucose ingestion. Co-ingestion of dairy milk with glucose, regardless of fat content, significantly altered lipid profiles although full-fat milk more substantially modulated lipid profiles. For the identified lipid biomarkers, 68.0% and 66.7% of the lipids significantly increased at 90 and 180 min, respectively, while phosphatidylcholines (GPs) contributed most for the significant increase. Comparative lipidomics analysis indicated that both types of dairy milk induced significant changes in several lipid pathways, including glycerophospholipid metabolism and α-linolenic acid metabolism, to protect against postprandial hyperglycemia. In summary, our comparative lipidomics results suggested that dairy milk-mediated lipid modulation may be an effective dietary approach to reduce the risk of metabolic diseases among those with prediabetes.

Milk Phospholipid Profiling Among Japanese Women with Differing Docosahexaenoic Acid Levels

To characterize the milk phospholipids (PLs) profile using phosphorus-31 nuclear magnetic resonance (³¹P-NMR) and to investigate the effect of elevated milk docosahexaenoic acid (DHA) levels on PLs profiles in Japanese mothers.

Methods

Milk samples from eligible patients with high and low DHA from a former cross-sectional study (n = 20; n = 10 for each group) were included. Fifteen milk PLs were analyzed using ³¹P-NMR, and the profiles were compared group-wise using Mann-Whitney U-test. The P value of <0.05 was considered statistically significant.

Results

The median DHA content in milk was 1.13% and 0.29% for the high and low milk DHA groups, respectively. Twelve PLs, excluding lysophosphatidylserine, cardiolipin, and phosphatidylglycerol, were detected in all participants with 100% positive results. The median concentrations and proportions of total PLs, sphingophospholipids, and glycerophospholipids were comparable between groups. The proportions of choline-containing glycerophospholipid were significantly higher in the high milk DHA group than that in the low milk DHA group (24.09% [median, interquartile range: 23.08%-26.38%] and 21.41% [20.74%-22.84%], P = 0.019). Although the proportions of phosphatidylinositol were significantly lower in the high milk DHA group than that in the low milk DHA group (6.62% [5.75%-6.72%] versus 7.63% [7.11%-8.16%], P = 0.002), while that of phosphatidylcholine (21.90% [18.51%-23.22%] versus 19.78% [18.17%-20.26%], P = 0.059) and alkyl-acyl phosphatidylcholine (0.60% [0.40%-0.74%] versus 0.33% [0.14%-0.51%], P = 0.059) were higher in the former than that in the latter.

Conclusions

Our results were comparable to that of the previous literature. Large variations in the milk DHA might affect the composition of choline-containing glycerophospholipids in Japanese mothers. However, possible confounders were not excluded in the study populations.

Invited review: Milk fat globule membrane-A possible panacea for neurodevelopment, infections, cardiometabolic diseases, and frailty

Milk is an evolutionary benefit for humans. For infants, it offers optimal nutrients for normal growth, neural development, and protection from harmful microbes. Humans are the only mammals who drink milk throughout their life. Lipids in colostrum originate mostly from milk fat globule membrane (MFGM) droplets extruded from the mammary gland. The MFGM gained much interest as a potential nutraceutical, due to their high phospholipid (PL), ganglioside (GD), and protein contents. In this review, we focused on health effects of MFGM ingredients and dairy food across the life span, especially on neurodevelopment, cardiometabolic health, and frailty in older adults. The MFGM supplements to infants and children reduced gastrointestinal and respiratory tract infections and improved neurodevelopment due to the higher content of protein, PL, and GD in MFGM. The MFGM formulas containing PL and GD improved brain myelination and fastened nerve conduction speed, resulting in improved behavioral developments. Administration of MFGM-rich ingredients improved insulin sensitivity and decreased inflammatory markers, LDL-cholesterol, and triglycerides by lowering intestinal absorption of cholesterol and increasing its fecal excretion. The MFGM supplements, together with exercise, improved ambulatory activities, leg muscle mass, and muscle fiber velocity in older adults. There are great variations in the composition of lipids and proteins in MFGM products, which make comparisons of the different studies impossible. In addition, investigations of the individual MFGM components are required to evaluate their specific effects and molecular mechanisms. Although we are currently only beginning to understand the possible health effects of MFGM products, the current MFGM supplementation trials as presented in this review have shown significant clinical health benefits across the human life span, which are worth further investigation.

Correlations of Fat Content in Human Milk with Fat Droplet Size and Phospholipid Species

Fat globule size and phospholipid (PL) content in human milk (HM) were investigated. HM was classified into three groups depending on fat content (A < B < C). PL content (mg/100 g HM) was significantly higher in the C group (p < 0.05), indicating its positive relationship with HM fat content. When the PL content was normalized (mg/g fat), that of group A was significantly higher (p < 0.05) and fat droplet size in group C was slightly larger, suggesting that HM fat content is affected by fat droplet numbers to a larger extent than by fat droplet size. A correlation between PC and SM content in HM was observed regardless of fat content, while correlation between PE and either PC or SM increased in the order of C > B > A, hence the composition and content of PL species in HM varied according to its fat content.

Comprehensive analysis of fatty acids in human milk of four Asian countries

Human milk lipids provide not only energy but also indispensable bioactive components such as essential fatty acids. To establish the recommended daily intake value and guidelines for infant formula, a reference library of fatty acid composition has been generated from 4 Asian countries (South Korea, China, Vietnam, and Pakistan). Regardless of country, palmitic acid (C16:0), linoleic acid (C18:1), and linolenic acid (C18:2) were the 3 most abundant fatty acids in human milk and account for more than 75% of total fatty acids (total FA). However, there were several considerable differences between fatty acids, particularly n-3 and n-6 (omega-3 and omega-6) groups. Chinese mothers' milk had a high concentration of linoleic acid at 24.38 ± 10.02% of total FA, which may be due to maternal diet. Among the 4 countries, Pakistani mothers' milk contained a high amount of saturated fatty acid (56.83 ± 5.96% of total FA), and consequently, polyunsaturated fatty acids, including n-3 and n-6, were significantly lower than in other countries. It is noteworthy that docosahexaenoic acid (DHA) in Pakistani mothers' milk was 44.8 ± 33.3 mg/L, which is only 25 to 30% of the levels in the other 3 countries, suggesting the need for DHA supplementation for infants in Pakistan. Moreover, the ratio of n-6 to n-3 was also remarkably high in Pakistani mothers' milk (15.21 ± 4.96), being 1.4- to 1.7-fold higher than in other countries. The average DHA:ARA ratio in Asian human milk was 1.01 ± 0.79. Korean mothers' milk showed a high DHA:ARA ratio, with a value of 1.30 ± 0.98, but Pakistani mothers' milk had a significantly lower value (0.42 ± 0.12). The fatty acid compositions and anthropometric data of mother (body mass index, age) did not show any correlation. The obtained data might provide information about human milk compositions in the Asian region that could benefit from setting up recommended nutrient intake and infant formula for Asian babies.

Anti-Infective, Anti-Inflammatory, and Immunomodulatory Properties of Breast Milk Factors for the Protection of Infants in the Pandemic From COVID-19

COVID-19 pandemic since the end of 2019 spreads worldwide, counting millions of victims. The viral invasion, systemic inflammation, and consequent organ failure are the gravest features of coronavirus disease 2019 (COVID-19), and they are associated with a high mortality rate. The aim of this study is to evaluate the role of breast milk in the COVID-19 pandemic, analyzing its antiviral, anti-inflammatory, and immunoregulatory effects due to its bioactive components, so numerous and important for the protection of infants. The study tried to demonstrate that all the components of human milk are capable of performing functions on all the pathogenic events recognized and described in COVID-19 disease. Those human milk factors are well-tolerated and practically free of side effects, so breast milk should become a research topic to discover therapies even in this epidemic. In the first part, the mechanisms of protection and defense of the breast milk elements will be delineated; in the second section, it will describe the human milk effects in viral infections and it will be hypothesized how the known mechanisms could act in COVID infection.

Variability of Lipids in Human Milk

Lipids in breastmilk play a critical role in infant growth and development. However, few studies have investigated sources of variability of both high- and low-abundant milk lipids. The objective of our study was to investigate individual and morning-evening differences in the human milk lipidome. In this study, a modified two-phase method (MTBE: Methanol 7:2) was validated for the extraction of lipids from human breastmilk. This method was then applied to samples from a group of 20 healthy women to measure inter- and intra-individual (morning versus evening) variability of the breastmilk lipidome. We report here the levels of 237 lipid species from 13 sub-classes using reversed-phase liquid chromatography mass spectrometry (RP-LCMS) and direct-infusion mass spectrometry (DI-MS). About 85% of lipid species showed stable inter-individual differences across time points. Half of lipid species showed higher concentrations in the evening compared with the morning, with phosphatidylethanolamines (PEs) and triacylglycerols (TAGs) exhibiting the largest changes. In morning and evening samples, the biological variation was greater for diacylglycerols (DAGs) and TAGs compared with phospholipids and sphingolipids, and the variation in DAGs and TAGs was greater in evening samples compared with morning samples. These results demonstrate that variation in the milk lipidome is strongly influenced by individual differences and time of day.

Comparative Lipidomics Analysis of Human Milk and Infant Formulas Using UHPLC-Q-TOF-MS

The lipidome and fatty acid composition of human milk and different infant formulas with animal- and/or plant-based fat sources are analyzed and compared in this study. The results obtained using positive and negative ionization modes indicate that there are 48 and 71 lipid species, respectively, that are common between the human milk and infant formulas. Moreover, the fatty acid composition in infant formulas varies significantly, depending on the fat source. Human milk is rich in triacylglycerols that contain linoleic acid, α-linolenic acid, arachidonic acid, and docosahexaenoic acid. Meanwhile, the triacylglycerols in IFB comprise long-chain fatty acids at the sn-1,3 position. Compared to human milk, IFC has the same level of sphingomyelin species. Based on univariate and multivariate analyses, there are 37, 34, 31, and 36 lipid species that can be used to distinguish between human milk and infant formulas. Overall, the results reported herein are useful in designing new milk formulas that better mimic human milk.

Quantitative profiling of glycerides, glycerophosphatides and sphingolipids in Chinese human milk with ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Human milk lipids are an important energy source and essential nutrients for the growth and development of infants. The UPLC/Q-TOF-MS was used to qualitatively and quantitatively analyze human milk lipids. Totally, 411 species of lipids were identified, in which the content of OPL was generally higher than that of OPO; SM (75.38 mg/L, 40.39%), PE (51.12 mg/L, 27.39%) and PC (40.10 mg/L, 21.49%) had the highest contents among polar lipids, mainly including SM42:2:2 (22.24 mg/L), PE36:2 (C18:0-C18:2, 21.39 mg/L) and PC36:2 (C18:0-C18:2, 19.80 mg/L). In human milk, TAG56:7 (137.14 mg/L), TAG56:8 (59.49 mg/L), TAG58:8 (65.90 mg/L) and TAG58:9 (49.99 mg/L) were the main sources of AA and DHA; PE was an important source of AA and DHA in polar lipids; and linoleic acyl in glycerides and phospholipids had higher contents than other polyunsaturated fatty acyls. These results provided the scientific basis for the simulation of human milk at molecular level.

Human breast milk as source of sphingolipids for newborns: comparison with infant formulas and commercial cow's milk

Background

In the past two decades, sphingolipids have become increasingly appreciated as bioactive molecules playing important roles in a wide array of pathophysiology mechanisms. Despite advances in the field, sphingolipids as nutrients remain little explored. Today the research is starting to move towards the study of the sphingomyelin content in human breast milk, recommended for feeding infants.

Methods

In the present study, we performed a lipidomic analysis in human breast milk in relation with maternal diet during pregnancy, in infant formulas, and in commercial whole and semi-skimmed milks for adults. Mediterranean, carnivorous and vegetarian diets were considered.

Results

The results showed that total sphingomyelin, ceramide and dihydroceramide species are independent on the diet. Interestingly, the milk sphingolipid composition is species-specific. In fact, infant formulas and commercial milks for adults have a lower level of total sphingomyelin and ceramide content than human breast milk with very different composition of each sphingolipid species.

Conclusions

We conclude that human breast milk is a better source of sphingolipids than infant formulas for baby nutrition with potential implications for the brain development and cognitive functions.

Dietary Milk Fat Globule Membrane Restores Decreased Intestinal Mucosal Barrier Development and Alterations of Intestinal Flora in Infant-Formula-Fed Rat Pups

SCOPE

Milk fat globule membrane (MFGM), which contains abundant polar lipids and glycoproteins, can narrow the gap in growth and development between breast-fed and infant-formula-fed babies. The objective of this study is to evaluate the effect of MFGM supplementation in infant formula on intestinal epithelium maturation, tight junctions, and gut colonization in rat pups.

METHODS AND RESULTS

Sprague Dawley rat pups consume one of the five diets from postnatal day 8, including rat breastfeeding (BF), infant formula (IF), and infant formula containing MFGM at 260 mg kg^-1 body weight (BW), 520 mg kg^-1 BW, or 1040 mg kg^-1 BW. Results show that MFGM supplementation in infant formula can facilitate intestinal mucosal barrier maturation via promoting intestinal proliferation and differentiation, and increasing tight junction proteins. In addition, compared with that of the IF pups, the intestinal flora composition of MFGM-supplemented pups is more similar to that of BF pups.

CONCLUSION

MFGM supplementation in infant formula can restore the intestinal development in infant-formula-fed pups, which suggests that the supplementation of MFGM in infant formula can better mimic breast milk.

EFFECT OF PASTEURIZATION ON THE ANTIOXIDANT AND OXIDANT PROPERTIES OF HUMAN MILK

Objective:

To evaluate the effect of pasteurization on antioxidant and oxidant properties of human milk.

Methods:

42 samples of milk before and after pasteurisation were used to evaluate the antioxidant activity by the ferric reducing capacity and by scavenging the 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical. Lipid peroxidation was estimated by the concentration of malondialdehyde product using the thiobarbituric acid reactive substances assay and by the evaluation of advanced oxidation protein products.

Results:

No significant difference was observed in fresh human milk and after pasteurization in relation to antioxidant properties determined by the ferric reducing capacity (50.0±3.4% and 48.8±3.0%, respectively) and by scavenging the 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical (28.9±1.5% and 31.2±1.3%, respectively). The results of malondialdehyde (62.6±4.1 and 64.3±3.6 µM/mg) and protein oxidation products (59.4±3.4 and 54.2±3.8 µM/L) of fresh and pasteurized milk, respectively, did not exhibited any significant difference.

Conclusions:

This data showed that human milk has an important antioxidant activity and that the pasteurizing process does not influence the antioxidant capacity, avoiding the peroxidation of breast milk lipids and the formation of advanced protein oxidation products.

Comparative Lipidomic Study of Human Milk from Different Lactation Stages and Milk Formulas

In this report, we present a detailed comparison of the lipid composition of human milk (HM) and formula milk (FM) targeting different lactation stages and infant age range. We studied HM samples collected from 26 Polish mothers from colostrum to 19 months of lactation, along with FM from seven brands available on the Polish market (infant formula, follow-on formula and growing-up formula). Lipid extracts were analysed using liquid chromatography coupled to high-resolution mass spectrometry (LC-Q-TOF-MS). We found that the lipid composition of FM deviates significantly from the HM lipid profile in terms of qualitative and quantitative differences. FM had contrasting lipid profiles mostly across brands and accordingly to the type of fat added but not specific to the target age range. The individual differences were dominant in HM; however, differences according to the lactation stage were also observed, especially between colostrum and HM collected in other lactation stages. Biologically and nutritionally important lipids, such as long-chain polyunsaturated fatty acids (LC-PUFAs) containing lipid species, sphingomyelines or ether analogues of glycerophosphoethanoloamines were detected in HM collected in all studied lactation stages. The observed differences concerned all the major HM lipid classes and highlight the importance of the detailed compositional studies of both HM and FM.

Simple and fast ultrasound-assisted method for mineral content and bioaccessibility study in infant formula by ICP OES

Infant formula (IF) constitutes the sole source of mineral intake for infants who are only fed IF. The assurance of the amount of minerals declared on the label and the mineral levels and their chemical forms present a major concern related to providing a good amount of nutrients for absorption by these children. Thus, the objectives of this study were: (i) to evaluate several sample preparation methods for minerals in IF; (ii) to validate an analytical method using an ultrasonic bath for simultaneous determination of the Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn contents in IF by ICP OES and (ii) to establish the optimum analytical conditions of the in vitro method to study the dialyzability of these minerals from IF. The ultrasound-assisted method was shown to conform to 'green chemistry principles', being simple, fast and low cost compared with reference methods. The results were similar to those obtained with reference methods (microwave-assisted acid digestion and dry ashing) with regard to selectivity, sensitivity and linearity (r2 > 0.999). The accuracy and the precision were verified using certified reference materials, with recoveries and coefficients of variation ranging from 91 to 105% and from 1.1 to 5.2%, respectively. For in vitro dialyzability, the conditions established in this study allowed including an overnight step between the gastric and gastrointestinal stages (accuracy and precision ranging from 81 to 108% and 0.4 to 6.3%, respectively), contributing to establishing an in vitro digestion method suitable for infant gastrointestinal conditions.

Effect of gestational age (preterm or full term) on lipid composition of the milk fat globule and its membrane in human colostrum

Human colostrum is the first milk secreted by the mother after birth and constitutes the ideal food for the newborn, because its chemical composition, rich in immunoglobulins, antimicrobial peptides, growth factors, bioactive lipids, and other important molecules, is perfectly adapted to the metabolic, digestive, and immunological immaturity of the newborn. An incomplete gestational period can affect the maturity of the mammary gland and its ability to secrete milk with the proper composition for the newborn's condition. Previous studies indicate that the mammary gland modulates the profiles of bioactive lipids present in the different phases of lactation from colostrum to mature milk. Given the key role played by the polar lipids (PL) (phospho- and sphingolipids) of the milk fat globule membrane (MFGM) in the immune system and cognitive development of the newborn, it is crucial to analyze whether the content and distribution of the PL are affected by gestation period. Therefore, this study aimed to determine the milk fat globule (MFG) and MFGM lipid compositions of human colostrum samples from 20 healthy preterm and full-term mothers. Lipid characterization using chromatographic techniques (gas chromatograph mass spectrometry and HPLC-evaporative light-scattering detection) revealed differences related to length of gestation in the profiles of lipid classes and fatty acid and triacylglyceride contents of colostrum. This comparative analysis leads to noteworthy outcomes about the changing roles of the PL, considering the preterm or full-term condition. We found a lack of correlation of some PL (such as phosphatidylcholine, phosphatidylinositol, and phosphatidylserine) with the delivery term; these could be denoted as structural category lipids. However, sphingomyelin and phosphatidyl-ethanolamine exhibited trends to decrease in full-term colostrum, indicating that in the final stage of pregnancy specific accretion of some PL occurs, which should be denoted as a nutritional redistribution.

Comprehensive Characterization of Bovine Milk Lipids: Phospholipids, Sphingolipids, Glycolipids, and Ceramides

A comprehensive survey on phospholipids (PLs), sphingolipids, glycolipids, and ceramides (Cer) of bovine milk was conducted by liquid chromatography tandem-mass spectrometry. A total of 514 species belonging to 15 classes were identified by an automated search tool (LipidSearch) and a manual analysis of MS2 spectra. Over 60 species were detected for the classes of phosphatidylcholine (PC), phosphatidylinositol, phosphatidylserine, and sphingomyelin (SM), between 20 and 45 species for phosphatidylethanolamine (PE), phosphatidic acid (PA), and lactosylceramide (LacCer), and between 7 and 20 species for phosphatidylglycerol (PG), lyso-phosphatidylcholine, lyso-phosphatidylethanolamine, glucosylceramide (GluCer), PC-plasmalogen (PC-P), PE-plasmalogen, ganglioside, and Cer. The structural assignment for PL classes is straightforward based on class-specific product ion/neutral losses and fatty acid-related product ions. By contrast, structural determination of lipid classes containing a backbone of sphingoid bases (SM, GluCer, LacCer, ganglioside, and Cer) is much more challenging, and combining MS2/MS3 information acquired in both positive and negative modes is sometimes needed. The quantification of all 15 classes of lipids was performed at the species level. A large variation in abundance was observed across the lipid classes; PC, PE, and SM are the most abundant polar lipid classes, with concentrations reaching 120, 150, and 90 μmol/L, respectively, whereas PA, PG, and PC-P are present at very low levels (<1.5 μmol/L) and the remaining classes at an intermediate level (2-45 μmol/L). This is the first comprehensive characterization of minor lipid classes from bovine milk and the information provided can be used as a reference for studying milk lipids.

Sources, Production, and Clinical Treatments of Milk Fat Globule Membrane for Infant Nutrition and Well-Being

Research on milk fat globule membrane (MFGM) is gaining traction. The interest is two-fold; on the one hand, it is a unique trilayer structure with specific secretory function. On the other hand, it is the basis for ingredients with the presence of phospho- and sphingolipids and glycoproteins, which are being used as food ingredients with valuable functionality, in particular, for use as a supplement in infant nutrition. This last application is at the center of this Review, which aims to contribute to understanding MFGM's function in the proper development of immunity, cognition, and intestinal trophism, in addition to other potential effects such as prevention of diseases including cardiovascular disease, impaired bone turnover and inflammation, skin conditions, and infections as well as age-associated cognitive decline and muscle loss. The phospholipid composition of MFGM from bovine milk is quite like human milk and, although there are some differences due to dairy processing, these do not result in a chemical change. The MFGM ingredients, as used to improve the formulation in different clinical studies, have indeed increased the presence of phospholipids, sphingolipids, glycolipids, and glycoproteins with the resulting benefits of different outcomes (especially immune and cognitive outcomes) with no reported adverse effects. Nevertheless, the precise mechanism(s) of action of MFGM remain to be elucidated and further basic investigation is warranted.

Plasma Metabolome Alterations Associated with Extrauterine Growth Restriction

Very preterm infants (VPI, born at or before 32 weeks of gestation) are at risk of adverse health outcomes, from which they might be partially protected with appropriate postnatal nutrition and growth. Metabolic processes or biochemical markers associated to extrauterine growth restriction (EUGR) have not been identified. We applied untargeted metabolomics to plasma samples of VPI with adequate weight for gestational age at birth and with different growth trajectories (29 well-grown, 22 EUGR) at the time of hospital discharge. A multivariate analysis showed significantly higher levels of amino-acids in well-grown patients. Other metabolites were also identified as statistically significant in the comparison between groups. Relevant differences (with corrections for multiple comparison) were found in levels of glycerophospholipids, sphingolipids and other lipids. Levels of many of the biochemical species decreased progressively as the level of growth restriction increased in severity. In conclusion, an untargeted metabolomic approach uncovered previously unknown differences in the levels of a range of plasma metabolites between well grown and EUGR infants at the time of discharge. Our findings open speculation about pathways involved in growth failure in preterm infants and the long-term relevance of this metabolic differences, as well as helping in the definition of potential biomarkers.

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.

Comparative Lipidomic Analyses Reveal Different Protections in Preterm and Term Breast Milk for Infants

Aim: Neonates are notably vulnerable, however they have improved outcomes if they are fed human milk. Human milk lipids constitute the primary constituents of human milk and serve a pivotal role in safeguarding infants from diseases. We assessed the lipid differences between preterm and term human milk and predicted the prospective impacts of these lipids on the development of neonates. Methods and results: We collected colostrum from healthy breast-feeding mothers who had delivered either term or preterm infants. We analyzed the lipid profiles of preterm, as well as term human milk using an LC-MS/MS metabolomics strategy. The orthogonal partial least-squares discriminant analysis score plots revealed remarkable distinction of lipids in preterm and term human milk. In total, 16 subclasses of 235 differential lipids (variable importance in projection > 1, P < 0.05) were identified. Notably, phosphatidylethanolamine and phosphatidylcholine were robustly increased in preterm human milk, while diacylglycerol and ceramide were markedly decreased in preterm human milk. Pathway analysis revealed that these dysregulated lipids are closely associated with glycerophospholipid metabolism, sphingolipid metabolism, Reelin signaling in neurons, and LXR/RXR activation. Conclusion: The results show that the lipids in preterm and term human colostrum vary, which may be critical for neonatal development.

Phospholipid Composition and Fat Globule Structure I: Comparison of Human Milk Fat from Different Gestational Ages, Lactation Stages, and Infant Formulas

We compared phospholipids (PLs), PL fatty acid (FA) composition, and milk fat globule size and structure in human milk (n = 120) from mothers of full-term and preterm infants during lactation (colostrum, transition, 1 mo, 2 mo, and 3 mo) and 8 brands of infant formulas. The absolute quantification of PLs was analyzed using ³¹P NMR spectroscopy. Sphingomyelin was the dominant PLs (35.01 ± 3.31%) in human milk, whereas phosphatidylcholine and phosphatidylethanolamine were the dominant PLs in infant formulas. The PL content in preterm milk increased during lactation, whereas that in term milk remained stable. Saturated FAs (mainly 16:0 and 18:0) were the most abundant (>60%) PL FA in both preterm and term milk and increased throughout lactation. The mean diameter of milk fat globules in infant formulas was much smaller than that found in human milk (200 nm vs 5.63 μm). Significant differences were observed between human milk and infant formulas with regard to PLs, suggesting that more research is needed to mimic the PL profile in infant formulas.

Improved Neurodevelopmental Outcomes Associated with Bovine Milk Fat Globule Membrane and Lactoferrin in Infant Formula: A Randomized, Controlled Trial

OBJECTIVE

To evaluate neurodevelopment, growth, and health outcomes in infants receiving bovine milk fat globule membrane (MFGM) and lactoferrin in infant formula.

STUDY DESIGN

Healthy term infants were randomized to a cow's milk-based infant formula or MFGM + LF (a similar infant formula, with an added source of bovine milk fat globule membrane [bMFGM; whey protein-lipid concentrate, 5 g/L] and bovine lactoferrin [0.6 g/L]) through 365 days of age. The Bayley Scales of Infant Development, 3rd edition cognitive composite score at day 365 was the primary outcome. Secondary outcomes included tolerance measures through day 365, additional neurodevelopmental and language outcomes, growth, and medically confirmed adverse events through day 545.

RESULTS

Of 451 infants enrolled (control, 228; MFGM + LF, 223), 291 completed study feeding and Bayley-III testing at day 365 (control, 148; MFGM + LF, 143). The mean cognitive (+8.7), language (+12.3), and motor (+12.6) scores were higher (P < .001) for the MFGM + LF group; no differences were observed at day 545. Global development scores from day 120 to day 275 and attention at day 365 were significantly improved. Few group differences in day 545 neurodevelopmental outcomes were detected, however scores of some subcategories of the MacArthur-Bates Communicative Development Inventories were higher (P < .05) in the MFGM + LF group. The overall incidence of respiratory-associated adverse events and diarrhea were significantly lower for the MFGM + LF group through day 545.

CONCLUSIONS

Infants receiving formula with added bovine MFGM and bovine lactoferrin had an accelerated neurodevelopmental profile at day 365 and improved language subcategories at day 545. Formulas were associated with age-appropriate growth and significantly fewer diarrhea and respiratory-associated adverse events through 545 days of age. TRIAL REGISTRATION CLINICALTRIALS.GOV:: NCT02274883.

Dietary Polar Lipids and Cognitive Development: A Narrative Review

Polar lipids are amphiphilic lipids with a hydrophilic head and a hydrophobic tail. Polar lipids mainly include phospholipids and sphingolipids. They are structural components of neural tissues, with the peak rate of accretion overlapping with neurodevelopmental milestones. The critical role of polar lipids in cognitive development is thought to be mediated through the regulation of signal transduction, myelination, and synaptic plasticity. Animal products (egg, meat, and dairy) are the major dietary sources of polar lipids for children and adults, whereas human milk and infant formula provide polar lipids to infants. Due to the differences observed in both concentration and proportion of polar lipids in human milk, the estimated daily intake in infants encompasses a wide range. In addition, health authorities define neither intake recommendations nor guidelines for polar lipid intake. However, adequate intake is defined for 2 nutrients that are elements of these polar lipids, namely choline and DHA. To date, limited studies exist on the brain bioavailability of dietary polar lipids via either placental transfer or the blood-brain barrier. Nevertheless, due to their role in pre- and postnatal development of the brain, there is a growing interest for the use of gangliosides, which are sphingolipids, as a dietary supplement for pregnant/lactating mothers or infants. In line with this, supplementing gangliosides and phospholipids in wild-type animals and healthy infants does suggest some positive effects on cognitive performance. Whether there is indeed added benefit of supplementing polar lipids in pregnant/lactating mothers or infants requires more clinical research. In this article, we report findings of a review of the state-of-the-art evidence on polar lipid supplementation and cognitive development. Dietary sources, recommended intake, and brain bioavailability of polar lipids are also discussed.

31P NMR-Based Phospholipid Fingerprinting of Powdered Infant Formula

Infant formula (IF), regarded as the optimal substitute for human breast milk, is very important for infant growth and development. Phospholipids (PLs) are ubiquitous components of infant formula as they have good emulsifier properties in addition to their nutritional and biological functions. In this study, the PL contents in four different commercial IF brands (indicated as A, M, O, and W) were characterized and quantified using optimized ³¹P NMR spectroscopy. PLs (nine) were identified and quantified, and among these, phosphatidylethanolamine and sphingomyelin occurred at lower concentrations (5.72 and 8.89 mg/100 g, respectively) in IFs from brand O, whereas phosphatidic acid was higher (2.83 mg/100 g) in IFs from brand W. In summary, ³¹P NMR spectroscopy, combined with the multivariate data analysis, proved to be an effective analytical toolbox for evaluating the PL contents in IF and the comparative differences between IF brands.

Sphingomyelin in Brain and Cognitive Development: Preliminary Data

Sphingomyelin (SM) supports brain myelination, a process closely associated with cognitive maturation. The presence of SM in breast milk suggests a role in infant nutrition; however, little is known about SM contribution to healthy cognitive development. We investigated the link between early life dietary SM, later cognitive development and myelination using an exploratory observational study of neurotypical children. SM levels were quantified in infant nutrition products fed in the first three months of life and associated with myelin content (brain MRI) as well as cognitive development (Mullen scales of early learning; MSEL). Higher levels of SM were significantly associated with higher rates of change in verbal development in the first two years of life (r = 0.65, p < 0.001), as well as, higher levels of myelin content at 12–24 months, delayed onset and/or more prolonged rates of myelination in different brain areas. Second, we explored mechanisms of action using in vitro models (Sprague Dawley rat pups). In vitro data showed SM treatment resulted in increased proliferation [p = 0.0133 and p = 0.0434 at 4 and 10 d in vitro (DIV)], maturation (p = 0.467 at 4 d DIV) and differentiation (p = 0.0123 and p = 0.0369 at 4 and 10 DIV) of oligodendrocyte precursor cells (OPCs), as well as increased axon myelination (p = 0.0005 at 32 DIV). These findings indicate an impact of dietary SM on cognitive development in healthy children, potentially modulated by oligodendrocytes and increased axon myelination. Future research should include randomized controlled trials to substantiate efficacy of SM for cognitive benefits together with preclinical studies examining SM bioavailability and brain uptake.

Effects of milk fat globule membrane and its various components on neurologic development in a postnatal growth restriction rat model

BACKGROUND

Milk fat globule membrane (MFGM) is a component of breast milk that consists of glycosylated membrane-bound proteins, polar lipids and carbohydrates originating from the mammary gland plasma membrane. A commercially available bovine MFGM added to infant formula has been shown to improve cognitive development in infants at 12 months of age.

OBJECTIVE

Considering that MFGM is a complex mixture, our aim was to determine which component(s) may be leading to these cognitive outcomes.

METHODS

Growth-restricted rat pups were supplemented with one of five treatments: (a) bovine MFGM, (b) bovine phospholipid concentrate (PL), (c) sialic acid (SIA) at 200 mg/kg body weight (bw) SIA100, (d) SIA at 2 mg/kg bw and (e) nonfat milk as control. Pups were randomized, cross-fostered into litters of 17 pups per dam and supplemented from postnatal day (PD) 2 to PD 21. The following behavioral tests were performed at adulthood: T-Maze Spontaneous Alternation, Novel Object Recognition and Morris Water Maze. Hippocampus was isolated at PD14 and PD21. Expression of four genes were measured including brain-derived neurotrophic factor (BDNF), dopamine receptor 1, (Drd1), glutamate receptor (GluR-1) and ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialytransferase 4 (St8Sia4). Following behavioral testing, brains were collected for nonbiased stereology.

RESULTS

Increased expression of genes due to supplementation was most pronounced at the PD14 time point. The MFGM group exhibited higher T-Maze scores compared to the SIA group (P=.01), whereas the SIA100 group visited the novel object more frequently than the MFGM group in the Novel Object test (P=.02). No differences due to supplementation were found in the Morris Water Maze or nonbiased stereology, CONCLUSIONS: In this trial, MFGM, compared to its individual components, had the largest impact on neurodevelopment in rat pups through up-regulation of genes and improved T-Maze scores compared to the SIA group.

Metabolic phenotype of breast-fed infants, and infants fed standard formula or bovine MFGM supplemented formula: a randomized controlled trial

Formula-fed (FF) infants exhibit a different metabolic profile than breast-fed (BF) infants. Two potential mechanisms are the higher protein level in formula compared with breast milk and the removal of the milk fat and associated milk fat globule membranes (MFGM) during production of infant formula. To determine whether MFGM may impact metabolism, formula-fed infants were randomly assigned to receive either an MFGM isolate-supplemented experimental formula (EF) or a standard formula (SF) from 2 until 6 months and compared with a BF reference group. Infants consuming EF had higher levels of fatty acid oxidation products compared to infants consuming SF. Although the protein level in the study formula was approximately 12 g/L (lower than most commercial formulas), a metabolic difference between FF and BF remained such that FF infants had higher levels of amino acid catabolism by-products and a low efficiency of amino acid clearance (preference for protein metabolism). BF infants had higher levels of fatty acid oxidation products (preference for fat metabolism). These unique, energy substrate-driven metabolic outcomes did not persist after diet was shifted to weaning foods and appeared to be disrupted by complementary feeding. Our results suggest that MFGM may have a role in directing infant metabolism.

Quantification of Human Milk Phospholipids: the Effect of Gestational and Lactational Age on Phospholipid Composition

Human milk (HM) provides infants with macro- and micronutrients needed for growth and development. Milk phospholipids are important sources of bioactive components, such as long-chain polyunsaturated fatty acids (LC-PUFA) and choline, crucial for neural and visual development. Milk from mothers who have delivered prematurely (<37 weeks) might not meet the nutritional requirements for optimal development and growth. Using liquid chromatography tandem-mass spectrometry, 31 phospholipid (PL) species were quantified for colostrum (<5 days postpartum), transitional (≥5 days and ≤2 weeks) and mature milk (>2 weeks and ≤15 weeks) samples from mothers who had delivered preterm (n = 57) and term infants (n = 22), respectively. Both gestational age and age postpartum affected the PL composition of HM. Significantly higher concentrations (p < 0.05) of phosphatidylcholine (PC), sphingomyelin (SM) and total PL were found in preterm milk throughout lactation, as well as significantly higher concentrations (p < 0.002) of several phosphatidylethanolamine (PE), PC and SM species. Multivariate analysis revealed that PLs containing LC-PUFA contributed highly to the differences in the PL composition of preterm and term colostrum. Differences related to gestation decreased as the milk matured. Thus, gestational age may impact the PL content of colostrum, however this effect of gestation might subside in mature milk.

Chemistry of Human Breast Milk-A Comprehensive Review of the Composition and Role of Milk Metabolites in Child Development

Early nutrition has an enormous influence on a child's physiological function, immune system maturation, and cognitive development. Human breast milk (HBM) is recognized as the gold standard for human infant nutrition. According to a WHO report, breastfeeding is considered as an unequaled way of providing ideal food to the infant, which is required for his healthy growth and development. HBM contains various macronutrients (carbohydrates, proteins, lipids, and vitamins) as well as numerous bioactive compounds and interactive elements (growth factors, hormones, cytokines, chemokines, and antimicrobial compounds. The aim of this review is to summarize and discuss the current knowledge about metabolites, which are the least understood components of HBM, and their potential role in infant development. We focus on small metabolites (<1500 Da) and characterize the chemical structure and biological function of polar metabolites such as human milk oligosaccharides, nonprotein molecules containing nitrogen (creatine, amino acids, nucleotides, polyamines), and nonpolar lipids. We believe that this manuscript will provide a comprehensive insight into a HBM metabolite composition, chemical structure, and their role in a child's early life nutrition.

Lipid Profiling, Particle Size Determination, and in Vitro Simulated Gastrointestinal Lipolysis of Mature Human Milk and Infant Formula

Dairy technologists has attempted to produce "improved" infant formulas mimicking human milk by supplementation with bovine MFGM and/or phospholipids-enriched materials. The present study investigated and compared the lipid profile and particle sizes of mature human milk and infant formula fat globules (IF 1, IF 2, IF 3, and IF 4) and elucidated the relationship between physicochemical properties and in vitro simulated gastrointestinal lipolysis rate of the different milk samples. Despite having larger micron-sized fat globules, mature human milk demonstrated the highest gastrointestinal lipolysis rate with higher release of medium- and long-chain saturated fatty acids. In comparison, IF 3, which contained the lowest phospholipids content, demonstrated the lowest gastrointestinal lipolysis rate. Higher gastrointestinal lipolysis rate of mature human milk fat as compared to infant formula fats might be due to the presence of MFGM interfacial layer (phospholipids) surrounding the fat droplets which govern lipase activity on lipid droplets.

Fatty acid positional distribution (sn-2 fatty acids) and phospholipid composition in Chinese breast milk from colostrum to mature stage

This study quantified the fatty acid profile with emphasis on the stereo-specifically numbered (sn) 2 positional distribution in TAG and the composition of main phospholipids at different lactation stages. Colostrum milk (n 70), transitional milk (n 96) and mature milk (n 82) were obtained longitudinally from healthy lactating women in Shanghai. During lactation, total fatty acid content increased, with SFA dominating in fatty acid profile. A high ratio of n-6:n-3 PUFA was observed as 11:1 over lactation due to the abundance of linoleic acid in Chinese human milk. As the main SFA, palmitic acid showed absolute sn-2 selectivity, while oleic acid, linoleic acid and α-linolenic acid, the main unsaturated fatty acids, were primarily esterified at the sn-1 and sn-3 positions. Nervonic acid and C22 PUFA including DHA were more enriched in colostrum with an sn-2 positional preference. A total of three dominant phospholipids (phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM)) were analysed in the collected samples, and each showed a decline in amount over lactation. PC was the dominant compound followed by SM and PE. With prolonged breast-feeding time, percentage of PE in total phospholipids remained constant, but PC decreased, and SM increased. Results from this study indicated a lipid profile different from Western reports and may aid the development of future infant formula more suitable for Chinese babies.

Compositional Dynamics of the Milk Fat Globule and Its Role in Infant Development

Human milk is uniquely optimized for the needs of the developing infant. Its composition is complex and dynamic, driven primarily by maternal genetics, and to a lesser extent by diet and environment. One important component that is gaining attention is the milk fat globule (MFG). The MFG is composed of a triglyceride-rich core surrounded by a tri-layer membrane, also known as the milk fat globule membrane (MFGM) that originates from mammary gland epithelia. The MFGM is enriched with glycerophospholipids, sphingolipids, cholesterol, and proteins, some of which are glycosylated, and are known to exert numerous biological roles. Mounting evidence suggests that the structure of the MFG and bioactive components of the MFGM may benefit the infant by aiding in the structural and functional maturation of the gut through the provision of essential nutrients and/or regulating various cellular events during infant growth and immune education. Further, antimicrobial peptides and surface carbohydrate moieties surrounding the MFG might have a pivotal role in shaping gut microbial populations, which in turn may promote protection against immune and inflammatory diseases early in life. This review seeks to: (1) understand the components of the MFG, as well as maternal factors including genetic and lifestyle factors that influence its characteristics; (2) examine the potential role of this milk component on the intestinal immune system; and (3) delineate the mechanistic roles of the MFG in infant intestinal maturation and establishment of the microbiota in the alimentary canal.

Fingerprinting of Phospholipid Molecular Species from Human Milk and Infant Formula Using HILIC-ESI-IT-TOF-MS and Discriminatory Analysis by Principal Component Analysis

Phospholipid composition in the milk fat globule membrane (MFGM) fluctuates during the entire lactation period in order to suit the growing needs of newborn infants. The present study elucidated and relatively quantified phospholipid molecular species extracted from human milk (HM), mature human milk (MHM), and infant formulas (with or without MFGM supplementation) using hydrophilic liquid chromatography-electrospray ionization-ion trap-time of flight-mass spectrometry (HILIC-ESI-IT-TOF-MS) system. Principal component analysis was used to clarify the differences between phospholipid composition in HM, MHM, and infant formulas. HM and MHM contained high concentrations of sphingomyeline (HM: 107.61 μg/mL, MHM: 227.18 μg/mL), phosphatidylcholine (HM: 59.96 μg/mL, MHM: 50.77 μg/mL), and phosphatidylethanolamine (PE) (HM: 25.24 μg/mL, MHM: 31.76 μg/mL). Significant concentrations (<300 ng/mL) of arachidonic, eicosapentanoic, and docosahexanoic acids were found to esterify to PE in HM and MHM. Meanwhile, all infant formulas were found to contain high concentrations of phosphatidic acids indicating the possibility of degradation of the fortified MFGM either during processing or storage of the infant formulas.

Effects of infant formula composition on long-term metabolic health

Early nutrition may have long-lasting metabolic impacts in adulthood. Even though breast milk is the gold standard, most infants are at least partly formula-fed. Despite obvious improvements, infant formulas remain perfectible to reduce the gap between breastfed and formula-fed infants. Improvements such as reducing the protein content, modulating the lipid matrix and adding prebiotics, probiotics and synbiotics, are discussed regarding metabolic health. Numerous questions remain to be answered on how impacting the infant formula composition may modulate the host metabolism and exert long-term benefits. Interactions between early nutrition (composition of human milk and infant formula) and the gut microbiota profile, as well as mechanisms connecting gut microbiota to metabolic health, are highlighted. Gut microbiota stands as a key actor in the nutritional programming but additional well-designed longitudinal human studies are needed.

Bovine dairy complex lipids improve in vitro measures of small intestinal epithelial barrier integrity

Appropriate intestinal barrier maturation is essential for absorbing nutrients and preventing pathogens and toxins from entering the body. Compared to breast-fed infants, formula-fed infants are more susceptible to barrier dysfunction-associated illnesses. In infant formula dairy lipids are usually replaced with plant lipids. We hypothesised that dairy complex lipids improve in vitro intestinal epithelial barrier integrity. We tested milkfat high in conjugated linoleic acid, beta serum (SureStart™Lipid100), beta serum concentrate (BSC) and a ganglioside-rich fraction (G600). Using Caco-2 cells as a model of the human small intestinal epithelium, we analysed the effects of the ingredients on trans-epithelial electrical resistance (TEER), mannitol flux, and tight junction protein co-localisation. BSC induced a dose-dependent improvement in TEER across unchallenged cell layers, maintained the co-localisation of tight junction proteins in TNFα-challenged cells with increased permeability, and mitigated the TEER-reducing effects of lipopolysaccharide (LPS). G600 also increased TEER across healthy and LPS-challenged cells, but it did not alter the co-location of tight junction proteins in TNFα-challenged cells. SureStart™Lipid100 had similar TEER-increasing effects to BSC when added at twice the concentration (similar lipid concentration). Ultimately, this research aims to contribute to the development of infant formulas supplemented with dairy complex lipids that support infant intestinal barrier maturation.

Lipids in human milk

Fat is the main energy providing component in human milk and comprising a complex mixture of different lipid species, with quantitative dominance of triglycerides. After elucidating the fatty acid composition, more recent research has looked at influencing factors and the importance of specific lipids. Here we review quantitative aspects of maternal metabolism which contribute to the milk fatty acid composition, especially considering essential fatty acids and their long chain polyunsaturated derivatives. In this context studies with stable isotopes have indicated the importance of maternal body pools for mediating the effects of diet on milk composition. Furthermore, the importance of positioning of palmitic acid at the glycerol backbone of triglycerides is discussed, and the phospholipids of the milk fat globule membrane are described and examples for their potential importance for infant development are presented.