Dietary intake of a MFGM/EV-rich concentrate promotes accretion of very long odd-chain sphingolipids and increases lipid metabolic turnover at the whole-body level

Lipids from cow milk fat globule membranes (MFGMs) and extracellular vesicles (EVs) are considered beneficial for neurodevelopment, cognitive maintenance and human health in general. Nevertheless, it is largely unknown whether intake of infant formulas and medical nutrition products rich in these particles promote accretion of specific lipids and whether this affects metabolic homeostasis. To address this, we carried out a 16-week dietary intervention study where mice were supplemented with a MFGM/EV-rich concentrate, a control diet supplemented with a whey protein concentrate and devoid of milk lipids, or regular chow. Assessment of commonly used markers of metabolic health, including body weight, glucose intolerance and liver microanatomy, demonstrated no differences across the dietary regimes. In contrast, in-depth lipidomic analysis revealed accretion of milk-derived very long odd-chain sphingomyelins and ceramides in blood plasma and multiple tissues of mice fed the MFGM/EV diet. Furthermore, lipidomic flux analysis uncovered that mice fed the MFGM/EV diet have increased lipid metabolic turnover at the whole-body level. These findings help fill a long-lasting knowledge gap between the intake of MFGM/EV-containing foods and the health-promoting effects of their lipid constituents. In addition, the findings suggest that dietary sphingomyelins or ceramide-breakdown products with very long-chains can be used as structural components of cellular membranes, lipoprotein particles and signaling molecules that modulate metabolic homeostasis and health.

Milk fat globule membrane proteins are crucial in regulating lipid digestion during simulated in vitro infant gastrointestinal digestion

Products of lipolysis released during digestion positively affect the metabolism of newborns. In contrast to the 3-layer biological membranes covering human milk (HM) fat, the lipid droplets in infant milk formula (IMF) are covered by a single membrane composed of casein and whey proteins. To reduce the differences in lipid structure between IMF and HM, studies have used milk fat globule membrane (MFGM) components such as milk polar lipids (MPL) to prepare emulsions mimicking HM fat globules However, few studies have elucidated the effect of membrane proteins (MP) on lipid digestion in infants. In this study, 3 kinds of emulsions were prepared: One with MPL as the interfaced of lipid droplets (RE-1), one with membrane protein concentrate (MPC) (RE-2) as the interface of lipid droplets, and one with both MPL and MPC (1:2) as the co-interface of lipid droplets (RE-3). The interfacial coverage of the emulsions was confirmed by measuring the contents of MPL and MPC at the lipid droplet interface, and by confocal laser scanning microscopy analyzed. By controlling the homogenization intensity, the specific surface area of lipid droplets was controlled at the same level among the 3 emulsions. The stability constants of the emulsions varied, and RE-1 was the most stable. During simulated in vitro infant gastrointestinal digestion, the amount of free fatty acids (FFA) released from the lipid droplets was significantly higher from those with MPC at the interface (RE-2, RE-3) than from that with MPL at the interface (RE-1). The amount of FFA released at the end of intestinal digestion of RE-1, RE-2, and RE-3 was 255.00 ± 3.54 µmol,328.75 ± 5.30 µmol, 298.50 ± 9.19 µmol, respectively. Compared with the lipid droplets in RE-2, those with MPL at the interface (RE-1, RE-3) released more unsaturated fatty acids (USFAs) during digestion. The emulsifying activity index was highest in RE-3 (MPL and MPC co-interface). The presence of MPL at the emulsion interface increased the release of USFAs, while the presence of MPC increased the release of FFA. These results show that both MPL and MP are indispensable in the construction of MFGM. Understanding their effects on digestion can provide new strategies for the development of infant foods.

Milk Fat Globule Membranes for Mental Health across the Human Lifespan

The milk fat globule membrane (MFGM) contains bioactive proteins, carbohydrates, and lipids. Polar lipids found in the MFGM play a critical role in maintaining cell membrane integrity and neuronal signalling capacity, thereby supporting brain health. This review summarises the literature on the MFGM and its phospholipid constituents for improvement of mental health across three key stages of the human lifespan, i.e., infancy, adulthood, and older age. MFGM supplementation may improve mental health by reducing neuroinflammation and supporting neurotransmitter synthesis through the gut-brain axis. Fortification of infant formula with MFGMs is designed to mimic the composition of breastmilk and optimise early gut and central nervous system development. Early behavioural and emotional development sets the stage for future mental health. In adults, promising results suggest that MFGMs can reduce the negative consequences of situational stress. Preclinical models of age-related cognitive decline suggest a role for the MFGM in supporting brain health in older age and reducing depressive symptoms. While there is preclinical and clinical evidence to support the use of MFGM supplementation for improved mental health, human studies with mental health as the primary target outcome are sparce. Further high-quality clinical trials examining the potential of the MFGM for psychological health improvement are important.

Lipidomic Comparisons of Whole Cream Buttermilk Whey and Cheese Whey Cream Buttermilk of Caprine Milk

Buttermilk is a potential material for the production of a milk fat globule membrane (MFGM) and can be mainly classified into two types: whole cream buttermilk and cheese whey cream buttermilk (WCB). Due to the high casein micelle content of whole cream buttermilk, the removal of casein micelles to improve the purity of MFGM materials is always required. This study investigated the effects of rennet and acid coagulation on the lipid profile of buttermilk rennet-coagulated whey (BRW) and buttermilk acid-coagulated whey (BAW) and compared them with WCB. BRW has significantly higher phospholipids (PLs) and ganglioside contents than BAW and WCB. The abundance of arachidonic acid (ARA)- and eicosapentaenoic acid (EPA)-structured PLs was higher in WCB, while docosahexaenoic acid (DHA)-structured PLs were higher in BRW, indicating that BRW and WCB intake might have a greater effect on improving cardiovascular conditions and neurodevelopment. WCB and BRW had a higher abundance of plasmanyl PL and plasmalogen PL, respectively. Phosphatidylcholine (PC) (28:1), LPE (20:5), and PC (26:0) are characteristic lipids among BRW, BAW, and WCB, and they can be used to distinguish MFGM-enriched whey from different sources.

Comparative lipidomics analysis of in vitro lipid digestion of sheep milk: Influence of homogenization and heat treatment

This study investigated the changes in sheep milk lipids during in vitro gastrointestinal digestion in response to heat treatment (75°C/15 s and 95°C/5 min) and homogenization (200/50 bar) using lipidomics. Homogenized and pasteurized sheep milk had higher levels of polar lipids in gastric digesta emptied at 20 min than raw sheep milk. Intense heat treatment of homogenized sheep milk resulted in a reduced level of polar lipids compared with homogenized-pasteurized sheep milk. The release rate of free fatty acids during small intestinal digestion for gastric digesta emptied at 20 min followed the order: raw ≤ pasteurized < homogenized-pasteurized ≤ homogenized-heated sheep milk; the rate for gastric digesta emptied at 180 min showed a reverse order. No differences in the lipolysis degree were observed among differently processed sheep milks. These results indicated that processing treatments affect the lipid composition of digesta and the lipolysis rate but not the lipolysis degree during small intestinal digestion.

Proteomic Comparisons of Caprine Milk Whole Cream Buttermilk Whey and Cheese Whey Cream Buttermilk

Buttermilk, a potential material used to produce milk fat globule membrane (MFGM), is obtained as a byproduct of butter making from milk whole cream and cheese whey cream. This study investigated the effects of rennet and acid coagulation on the protein profiles of buttermilk rennet-coagulated whey (BRW) and buttermilk acid-coagulated whey (BAW). They were compared to those of whey cream buttermilk (WCB). Rennet coagulation was more efficient in removing casein, while retaining more IgG and lactoferrin than acid coagulation. BRW had more MFGM than BAW. Butyrophilin, xanthine dehydrogenase, and mucin1 were significantly higher (P < 0.05) in BRW, while fatty acid-binding protein 3 was enriched in BAW. KEGG analysis showed that complement and coagulation cascades had the greatest differences, and the abundance of proteins involved in this signaling pathway in BRW and BAW was higher, suggesting their potential anticoagulant and anti-inflammatory activity. BAW had higher apolipoprotein A4 and transcobalamin 2, which are essential carriers for transporting long-chain fatty acids and vitamin B12 from the intestine to the blood. Therefore, BAW intake might improve lipids and vitamin B12 absorption. This study can help deepen the understanding of protein composition of MFGM-enriched whey and facilitate the production of MFGM proteins for infants and old-aged populations.

Lipidomic Characterization of Whey Concentrates Rich in Milk Fat Globule Membranes and Extracellular Vesicles

Lipids from milk fat globule membranes (MFGMs) and extracellular vesicles (EVs) are considered beneficial for cognitive development and human health. Milk-derived whey concentrates rich in these lipids are therefore used as ingredients in infant formulas to mimic human milk and in medical nutrition products to improve the metabolic fitness of adults and elderly people. In spite of this, there is no consensus resource detailing the multitude of lipid molecules in whey concentrates. To bridge this knowledge gap, we report a comprehensive and quantitative lipidomic resource of different whey concentrates. In-depth lipidomic analysis of acid, sweet, and buttermilk whey concentrates identified 5714 lipid molecules belonging to 23 lipid classes. The data show that the buttermilk whey concentrate has the highest level of fat globule-derived triacylglycerols and that the acid and sweet whey concentrates have the highest proportions of MFGM- and EV-derived membrane lipids. Interestingly, the acid whey concentrate has a higher level of cholesterol whereas sweet whey concentrate has higher levels of lactosylceramides. Altogether, we report a detailed lipid molecular compendium of whey concentrates and lay the groundwork for using in-depth lipidomic technology to profile the nutritional value of milk products and functional foods containing dairy-based concentrates.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

The Effect of the Feeding System on Fat Deposition in Yak Subcutaneous Fat

Fat deposition is very important to the growth and reproduction of yaks. In this study, the effect of the feeding system on fat deposition in yaks was explored by transcriptomics and lipidomics. The thickness of the subcutaneous fat in yaks under stall (SF) and graze feeding (GF) was evaluated. The transcriptomes and lipidomes of the subcutaneous fat in yaks under different feeding systems were detected by RNA-sequencing (RNA-Seq) and non-targeted lipidomics based on ultrahigh-phase liquid chromatography tandem mass spectrometry (UHPLC-MS), respectively. The differences in lipid metabolism were explored, and the function of differentially expressed genes (DEGs) was evaluated by gene ontology (GO) and Kyoto encyclopedia of genes and genome (KEGG) analysis. Compared with GF yaks, SF yaks possessed stronger fat deposition capacity. The abundance of 12 triglycerides (TGs), 3 phosphatidylethanolamines (PEs), 3 diglycerides (DGs), 2 sphingomyelins (SMs) and 1 phosphatidylcholine (PC) in the subcutaneous fat of SF and GF yaks was significantly different. Under the mediation of the cGMP-PKG signaling pathway, the blood volume of SF and GF yaks may be different, which resulted in the different concentrations of precursors for fat deposition, including non-esterified fatty acid (NEFA), glucose (GLU), TG and cholesterol (CH). The metabolism of C16:0, C16:1, C17:0, C18:0, C18:1, C18:2 and C18:3 in yak subcutaneous fat was mainly realized under the regulation of the INSIG1, ACACA, FASN, ELOVL6 and SCD genes, and TG synthesis was regulated by the AGPAT2 and DGAT2 genes. This study will provide a theoretical basis for yak genetic breeding and healthy feeding.

Evidence for human milk as a biological system and recommendations for study design-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 4

Human milk contains all of the essential nutrients required by the infant within a complex matrix that enhances the bioavailability of many of those nutrients. In addition, human milk is a source of bioactive components, living cells and microbes that facilitate the transition to life outside the womb. Our ability to fully appreciate the importance of this matrix relies on the recognition of short- and long-term health benefits and, as highlighted in previous sections of this supplement, its ecology (i.e., interactions among the lactating parent and breastfed infant as well as within the context of the human milk matrix itself). Designing and interpreting studies to address this complexity depends on the availability of new tools and technologies that account for such complexity. Past efforts have often compared human milk to infant formula, which has provided some insight into the bioactivity of human milk, as a whole, or of individual milk components supplemented with formula. However, this experimental approach cannot capture the contributions of the individual components to the human milk ecology, the interaction between these components within the human milk matrix, or the significance of the matrix itself to enhance human milk bioactivity on outcomes of interest. This paper presents approaches to explore human milk as a biological system and the functional implications of that system and its components. Specifically, we discuss study design and data collection considerations and how emerging analytical technologies, bioinformatics, and systems biology approaches could be applied to advance our understanding of this critical aspect of human biology.

Efficient in vitro digestion of lipids and proteins in bovine milk fat globule membrane ingredient (MFGMi) and whey-casein infant formula with added MFGMi

The relative immaturity of the infant digestive system has the potential to affect the bioavailability of dietary lipids, proteins, and their digested products. We performed a lipidomic analysis of a commercial bovine milk fat globule membrane ingredient (MFGMi) and determined the profile of lipids and proteins in the bioaccessible fraction after in vitro digestion of both the ingredient and whey-casein-based infant formula without and with MFGMi. Test materials were digested using a static 2-phase in vitro model, with conditions simulating those in the infant gut. The extent of digestion and the bioaccessibility of various classes of neutral and polar lipids were monitored by measuring a wide targeted lipid profile using direct infusion-mass spectrometry. Digestion of abundant proteins in the ingredient and whey-casein infant formula containing the ingredient was determined by denaturing PAGE with imaging of Coomassie Brilliant Blue stained bands. Cholesterol esters, diacylglycerides, triacylglycerides, phosphatidylcholines, and phosphatidylethanolamines in MFGMi were hydrolyzed readily during in vitro digestion, which resulted in marked increases in the amounts of free fatty acids and lyso-phospholipids in the bioaccessible fraction. In contrast, sphingomyelins, ceramides, and gangliosides were largely resistant to simulated digestion. Proteins in MFGMi and the infant formulas also were hydrolyzed efficiently. The results suggest that neutral lipids, cholesterol esters, phospholipids, and proteins in MFGMi are digested efficiently during conditions that simulate the prandial lumen of the stomach and small intestine of infants. Also, supplementation of whey-casein-based infant formula with MFGMi did not appear to alter the profiles of lipids and proteins in the bioaccessible fraction after digestion.

Naturally forming benzoic acid orientates perilipin to facilitate glyceride-type polyunsaturated fatty acid degradation via fermentation behavior

Naturally forming benzoic acid in fermented dairy products accumulates in organisms and biomagnifies through collateral transport. The association between benzoic acid agglomeration and susceptible lipid nutrients remains obscure. Horizontal analysis of lipidomic alteration in response to benzoic acid was conducted and the spatially proteomic map was constructed using label-free quantitative proteomics. From synergistic integration of multi-omics in benzoic acid accumulated fermented goat milk model, the biological processes of significant proteins mostly focused on glyceride-type polyunsaturated fatty acids degradation (143.818 ± 0.51 mg/kg to 104.613 ± 0.29 mg/kg). As a physiological barrier shield, perilipin, which is coated on the surface of lipid droplets, protects triacylglycerols from cytosolic lipases, thus preventing triglyceride hydrolysis. The expression of perilipin decreased by 90% compared with the control group, leading to the decrease of triglycerides. Benzoic acid suppressed phosphatidylethanolamines and phosphatidylcholines synthesis by attenuating choline phosphotransferase and ethanolamine phosphotransferase. Less diglyceride generated by the dephosphorylation of phosphatidic acid entered choline phosphotransferase and ethanolamine phosphotransferase-mediated glycerophospholipid metabolisms. Fermentation of goat milk at a low temperature and less incubation time leads to the production of less benzoic acid and mitigation of lipid nutrient loss. The present study delineated the molecular landscape of fermented goat milk containing endogenous benzoic acid and further dissected the trajectory guiding lipid alteration to advance control of benzoic acid residue.

Analysis of milk with liquid chromatography–mass spectrometry: a review

As a widely consumed foodstuff, milk and dairy products are increasingly studied over the years. At the present time, milk profiling is used as a benchmark to assess the properties of milk. Modern biomolecular mass spectrometers have become invaluable to fully characterize the milk composition. This review reports the analysis of milk and its components using liquid chromatography coupled with mass spectrometry (LC–MS). LC–MS analysis as a whole will be discussed subdivided into the major constituents of milk, namely, lipids, proteins, sugars and the mineral fraction.

Mechanisms affecting the gut of preterm infants in enteral feeding trials: a nested cohort within a randomised controlled trial of lactoferrin

OBJECTIVE

To determine the impact of supplemental bovine lactoferrin on the gut microbiome and metabolome of preterm infants.

DESIGN

Cohort study nested within a randomised controlled trial (RCT). Infants across different trial arms were matched on several clinical variables. Bacteria and metabolite compositions of longitudinal stool and urine samples were analysed to investigate the impact of lactoferrin supplementation.

SETTING

Thirteen UK hospitals participating in a RCT of lactoferrin.

PATIENTS

479 infants born <32 weeks' gestation between June 2016 and September 2017.

RESULTS

10 990 stool and 22 341 urine samples were collected. Analyses of gut microbiome (1304 stools, 201 infants), metabolites (171 stools, 83 infants; 225 urines, 90 infants) and volatile organic compounds (314 stools, 117 infants) were performed. Gut microbiome Shannon diversity at 34 weeks corrected age was not significantly different between infants in the lactoferrin (mean=1.24) or placebo (mean=1.06) groups (p=0.11). Lactoferrin receipt explained less than 1% variance in microbiome compositions between groups. Metabolomic analysis identified six discriminative features between trial groups. Hospital site (16%) and postnatal age (6%) explained the greatest variation in microbiome composition.

CONCLUSIONS

This multiomic study identified minimal impacts of lactoferrin but much larger impacts of hospital site and postnatal age. This may be due to the specific lactoferrin product used, but more likely supports the findings of the RCT in which this study was nested, which showed no impact of lactoferrin on reducing rates of sepsis. Multisite mechanistic studies nested within RCTs are feasible and help inform trial interpretation and future trial design.

BoMiProt 2.0: An update of the bovine milk protein database

Milk is a biofluid with various functions, containing carbohydrates, lipids, proteins, vitamins, and minerals. Owing to its importance and availability of vast proteomics information, our research group designed a database for bovine milk proteins (N = 3159) containing the primary and secondary information called BoMiProt. Due to the gaining interest and intensively published literature in the last three years, BoMiProt has been upgraded with newer identified proteins (N = 7459) from peer-reviewed journals, significantly expanding the database from different milk fractions (e.g., whey, fat globule membranes, and exosomes). Additionally, class, architecture, topology, and homology, structural classification of proteins, known and predicted disorder, predicted transmembrane helices, and structures have been included. Each protein entry in the database is thoroughly cross-referenced, including 1392 BoMiProt defined proteins provided with secondary information, such as protein function, biochemical properties, post-translational modifications, significance in milk, domains, fold, AlphaFold predicted models and crystal structures. The proteome data in the database can be retrieved using several search parameters using protein name, accession IDs, and FASTA sequence. Overall, BoMiProt represents an extensive compilation of newer proteins, including structural, functional, and hierarchical information, to help researchers better understand mammary gland pathophysiology, including their potential application in improving the nutritional quality of dairy products.

Milk polar lipids composition and functionality: a systematic review

Polar lipids including glycerophospholipids and sphingophospholipids are important nutrients and milk is a major source, particularly for infants. This systematic review describes the human and bovine milk polar lipid composition, structural organization, sources for formulation, and physiological functionality. A total of 2840 records were retrieved through Scopus, 378 were included. Bovine milk is a good source of polar lipids, where yield and composition are highly dependent on the choice of dairy streams and processing. In milk, polar lipids are organized in the milk fat globule membrane as a tri-layer encapsulating triglyceride. The overall polar lipid concentration in human milk is dependent on many factors including lactational stage and maternal diet. Here, reasonable ranges were determined where possible. Similar for bovine milk, where differences in milk lipid concentration proved the largest factor determining variation. The role of milk polar lipids in human health has been demonstrated in several areas and critical review indicated that brain, immune and effects on lipid metabolism are best substantiated areas. Moreover, insights related to the milk fat globule membrane structure-function relation as well as superior activity of milk derived polar lipid compared to plant-derived sources are emerging areas of interest regarding future research and food innovations.

Impacts of Formula Supplemented with Milk Fat Globule Membrane on the Neurolipidome of Brain Regions of Piglets

The milk fat globule membrane (MFGM) appears to play an important role in infant neurocognitive development; however, its mechanism(s) of action remains unclear. This study aimed to investigate the role of a dietary MFGM supplement on the lipid profiles of different neonatal brain regions. Ten-day-old male piglets (4−5 kg) were fed unsupplemented infant formula (control, n = 7) or an infant formula supplemented with low (4%) or high (8%) levels of MFGM (n = 8 each) daily for 21 days. Piglets were then euthanized, and brain tissues were sectioned. Untargeted liquid chromatography-mass spectrometry lipidomics was performed on the cerebellum, hippocampus, prefrontal cortex, and the rest of the brain. The analyses identified 271 and 171 lipids using positive and negative ionization modes, respectively, spanning 16 different lipid classes. MFGM consumption did not significantly alter the lipidome in most brain regions, regardless of dose, compared to the control infant formula. However, 16 triacylglyceride species were increased in the hippocampus (t-test, p-value < 0.05) of the high-supplemented piglets. Most lipids (262 (96.7%) and 160 (93.6%), respectively) differed significantly between different brain regions (ANOVA, false discovery rate corrected p-value < 0.05) independent of diet. Thus, this study highlighted that dietary MFGM altered lipid abundance in the hippocampus and detected large differences in lipid profiles between neonatal piglet brain regions.

The role of orally ingested milk fat globule membrane on intestinal barrier functions evaluated with a suckling rat pup supplementation model and a human enterocyte model

Milk fat globule membrane (MFGM), the membrane surrounding secreted fat droplets in milk, contains components involved in a wide range of bioprocesses including cell proliferation and differentiation. The intestine is relatively immature and permeable at birth. Since MFGM is partly resistant to digestion in infancy, we hypothesized that orally ingested MFGM promotes intestinal development by enhancing intestinal barrier functions in early life. An established suckling rat model was used; Sprague-Dawley rats were bred, and litters were culled to 10 pups/dam. Pups were supplemented orally with MFGM (0, 100, or 300 mg/kg/day) from postnatal day 1 to 20. Intestine samples were collected for histology, qRT-PCR, immunoblotting, and immunohistochemistry analysis. Additionally, differentiated Caco-2 cells were used to assess effects of MFGM on the human intestinal barrier. Control and MFGM-supplemented rat pups showed similar growth. Intestinal differentiation and expression of tight junction proteins in jejunum and colon were significantly increased by orally ingested MFGM, and MFGM supplementation significantly activated PI3K/Akt/mTOR, MAPK, and MLCK signaling pathways, suggesting that MFGM promotes intestinal development by triggering various signaling pathways. In human enterocytes (polarized Caco-2 cells), MFGM (400 µg/mL for 72 h) decreased permeability, as revealed by increased transepithelial electrical resistance. In Caco-2 cells, MFGM also enhanced expression of tight junction proteins, including claudin-4 and ZO-2. In conclusion, orally ingested MFGM may exert beneficial roles in intestinal development by activating various cell signaling pathways to upregulate tight junction proteins and thereby increasing intestinal barrier functions.

Advances in analysis, metabolism and mimicking of human milk lipids

Human milk lipids differ from the milk lipids of other mammals in composition and positional distribution of fatty acids. Analysis and detection technology of lipids is key to understanding milk lipids, and thus the concentrations, compositions and distribution characteristics of milk lipids are discussed. Differences between human milk lipids and their substitutes in form, composition and structure affect their digestion, absorption and function in infants. Characteristics and mimicking of human milk lipids have been intensively studied with the objective of narrowing the gap between human milk and infant formulae. Based on the existing achievements, further progress may be made by improving detection techniques, deepening knowledge of metabolic pathways and perfecting fat substitutes. This review detailed the characteristics of human milk lipids and related detection technologies with a view towards providing a clear direction for research on mimicking human milk lipids in formulae to further improve infant nutrition.

Roles of Milk Fat Globule Membrane on Fat Digestion and Infant Nutrition

Milk fats are present as globules emulsified in the aqueous phase of milk and stabilized by a delicate membrane architecture called milk fat globule membrane (MFGM). The unique structure and composition of the MFGM play an important role in fat digestion and the metabolic programming of neonates. The objective of this review is to compare the structure, composition, and physicochemical characteristics of fat globules in human milk, bovine milk, and infant formula. It provides an overview of the fat digestion process and enzymes in healthy infants, and describes the possible roles of the MFGM in association with factors affecting fat digestion. Lastly, the health benefits of the MFGM on infant nutrition and future perspectives are discussed with a focus on brain development, metabolic response, and gut health.

Glycoproteomic and Lipidomic Characterization of Industrially Produced Whey Protein Phospholipid Concentrate with Emphasis on Antimicrobial Xanthine Oxidase, Oxylipins and Small Milk Fat Globules

This work investigates the composition of whey protein phospholipid concentrate (WPPC), an underutilized dairy stream, and reveals that it is a source of many bioactive compounds that can benefit the immune system and gut health. Our glycoproteomics approach uncovered that proteins derived from the milk fat globule membrane (MFGM) represent 23% of the total protein relative abundance and identified 85 N-glycans. Released sialic acid, an additional marker of glycosylation, ranged from 1.2 to 2% of the total weight. Xanthine oxidase, a glycosylated marker of MFG bioactivity, was found in high abundance and displayed higher antimicrobial activity than bovine milk, despite its similar fat and solids content. An average MFG diameter of 2.64 ± 0.01 µm was found in liquid WPPC, compared to 4.78 ± 0.13 µm in bovine milk, which likely explains the unusually high presence of glycosylated membrane-bound proteins and phospholipids, whose total fatty acids accounted for 20% of the WPPC total fatty acid pool. Free and bound oxylipins (mainly derived from linoleic acid) were also identified, together with other less abundant anti-inflammatory lipid mediators derived from eicosapentaenoic acid and docosahexaenoic acid. Our study demonstrates that WPPC represents a promising starting material for bioactive compound extraction and a functional vehicle for the delivery of small MFGs.

A Double-Blind, Randomized Intervention Study on the Effect of a Whey Protein Concentrate on E. coli-Induced Diarrhea in a Human Infection Model

Infectious diseases are a major cause of morbidity and mortality worldwide. Nutritional interventions may enhance resistance to infectious diseases or help to reduce clinical symptoms. Here, we investigated whether a whey protein concentrate (WPC) could decrease diarrheagenic Escherichia coli-induced changes in reported stool frequency and gastrointestinal complaints in a double-blind, parallel 4-week intervention study. Subjects were randomly assigned to a whey hydrolysate placebo group, a low-dose WPC group or a high-dose WPC group. After 2 weeks of consumption, subjects (n = 121) were orally infected with a high dose of live but attenuated diarrheagenic E. coli (strain E1392/75-2A; 1E10 colony-forming units). Subjects recorded information on stool consistency and the frequency and severity of symptoms in an online diary. The primary outcome parameters were a change in stool frequency (stools per day) and a change in Gastrointestinal Symptom Rating Scale (GSRS) diarrhea score between the first and second days after infection. Neither dose of the whey protein concentrate in the dietary treatment affected the E. coli-induced increase in stool frequency or GSRS diarrhea score compared to placebo treatment. The composition of the microbiota shifted between the start of the study and after two weeks of consumption of the products, but no differences between the intervention groups were observed, possibly due to dietary guidelines that subjects had to adhere to during the study. In conclusion, consumption of the whey protein concentrate by healthy adults did not reduce diarrhea scores in an E. coli infection model compared to a whey hydrolysate placebo control.

Human milk cholesterol is associated with lactation stage and maternal plasma cholesterol in Chinese populations

BACKGROUND

Milk cholesterol concentrations throughout lactation were analyzed, and the relationship between maternal plasma cholesterol and milk cholesterol in various Chinese populations was examined.

METHODS

A sub-sample of 1138 lactating women was randomly selected from a large cross-sectional study in China (n = 6481). Milk cholesterol concentrations were determined by HPLC, and concentrations of maternal plasma lipids were determined by an automated biochemical analyzer.

RESULTS

The mean cholesterol concentrations were 200, 171, and 126 mg/L for colostrum, transitional milk, and mature milk, respectively. Cholesterol concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Concentrations of maternal plasma total cholesterol (TC) (p = 0.02) and low-density lipoprotein cholesterol (LDL-C) (p = 0.03) were significantly associated with milk cholesterol. Milk cholesterol concentrations varied among different ethnicities (Tibetan vs. Hui: 164 vs. 131 mg/L, p = 0.027) but not among different geographic regions.

CONCLUSIONS

The concentration of cholesterol in human milk changes dynamically throughout lactation. Milk cholesterol concentrations are significantly associated with maternal plasma concentrations of TC and LDL-C, and milk cholesterol concentrations vary across ethnicities in China.

IMPACT

Concentrations of milk cholesterol were measured in various Chinese populations. Cholesterol concentrations differ significantly between stages of lactation. Maternal plasma total cholesterol and low-density lipoprotein cholesterol are associated with milk cholesterol. Milk cholesterol concentrations vary across ethnicities in China.

Milk fat globule membrane attenuates high fat diet-induced neuropathological changes in obese Ldlr-/-.Leiden mice

BACKGROUND

Milk-fat globule membrane (MFGM) is a complex structure secreted by the mammary gland and present in mammalian milk. MFGM contains lipids and glycoproteins as well as gangliosides, which may be involved in myelination processes. Notably, myelination and thereby white matter integrity are often altered in obesity. Furthermore, MFGM interventions showed beneficial effects in obesity by affecting inflammatory processes and the microbiome. In this study, we investigated the impact of a dietary MFGM intervention on fat storage, neuroinflammatory processes and myelination in a rodent model of high fat diet (HFD)-induced obesity.

METHODS

12-week-old male low density lipoprotein receptor-deficient Leiden mice were exposed to a HFD, a HFD enriched with 3% whey protein lipid concentrate (WPC) high in MFGM components, or a low fat diet. The impact of MFGM supplementation during 24-weeks of HFD-feeding was examined over time by analyzing body weight and fat storage, assessing cognitive tasks and MRI scanning, analyzing myelinization with polarized light imaging and examining neuroinflammation using immunohistochemistry.

RESULTS

We found in this study that 24 weeks of HFD-feeding induced excessive fat storage, increased systolic blood pressure, altered white matter integrity, decreased functional connectivity, induced neuroinflammation and impaired spatial memory. Notably, supplementation with 3% WPC high in MFGM components restored HFD-induced neuroinflammation and attenuated the reduction in hippocampal-dependent spatial memory and hippocampal functional connectivity.

CONCLUSIONS

We showed that supplementation with WPC high in MFGM components beneficially contributed to hippocampal-dependent spatial memory, functional connectivity in the hippocampus and anti-inflammatory processes in HFD-induced obesity in rodents. Current knowledge regarding exact biological mechanisms underlying these effects should be addressed in future studies.

The untargeted lipidomic profile of quarter milk from dairy cows with subclinical intramammary infection by non-aureus staphylococci

This observational study determined the lipidome of cow milk during subclinical intramammary infection (IMI) by non-aureus staphylococci (NAS), also defined as coagulase-negative staphylococci, using an untargeted approach. Among the pathogens causing bovine IMI, NAS have become the most frequently isolated bacteria from milk samples. Although the application of system biology approaches to mastitis has provided pivotal information by investigating the transcriptome, proteome, peptidome, and metabolome, the milk lipidome during mammary gland inflammation remains undisclosed. To cover this gap, we determined the milk lipidome of 17 dairy cows with IMI caused by NAS (NAS-IMI), and we compared the results with those of healthy quarter milk from 11 cows. The lipidome was determined following a liquid chromatography-quadrupole time-of-flight mass spectrometry approach. Sixteen subclasses of lipids were identified in both groups of animals. From 2,556 measured lipids, the abundance of 597 changed more than 10-fold in quarter milk with NAS-IMI compared with healthy quarters. The results demonstrate the influence of NAS-IMI on the milk lipidome, implying significant changes in lipid species belonging to the family of triacylglycerols and sphingomyelins, and contribute to the understanding of inflammatory processes in the bovine udder, highlighting potential novel biomarkers for improving mastitis diagnostics.

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.

Milk Fat Globule Membrane Proteome and Micronutrients in the Milk Lipid Fraction: Insights into Milk Bioactive Compounds

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas.

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

Breast milk is an unbeatable food that covers all the nutritional requirements of an infant in its different stages of growth up to six months after birth. In addition, breastfeeding benefits both maternal and child health. Increasing knowledge has been acquired regarding the composition of breast milk. Epidemiological studies and epigenetics allow us to understand the possible lifelong effects of breastfeeding. In this review we have compiled some of the components with clear functional activity that are present in human milk and the processes through which they promote infant development and maturation as well as modulate immunity. Milk fat globule membrane, proteins, oligosaccharides, growth factors, milk exosomes, or microorganisms are functional components to use in infant formulas, any other food products, nutritional supplements, nutraceuticals, or even for the development of new clinical therapies. The clinical evaluation of these compounds and their commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale. In this work we focus on the compounds produced using milk components from other species such as bovine, transgenic cattle capable of expressing components of human breast milk or microbial culture engineering.

Comparative Proteomics of Milk Fat Globule Membrane (MFGM) Proteome across Species and Lactation Stages and the Potentials of MFGM Fractions in Infant Formula Preparation

Milk is a lipid-in-water emulsion with a primary role in the nutrition of newborns. Milk fat globules (MFGs) are a mixture of proteins and lipids with nutraceutical properties related to the milk fat globule membrane (MFGM), which protects them, thus preventing their coalescence. Human and bovine MFGM proteomes have been extensively characterized in terms of their formation, maturation, and composition. Here, we review the most recent comparative proteomic analyses of MFGM proteome, above all from humans and bovines, but also from other species. The major MFGM proteins are found in all the MFGM proteomes of the different species, although there are variations in protein expression levels and molecular functions across species and lactation stages. Given the similarities between the human and bovine MFGM and the bioactive properties of MFGM components, several attempts have been made to supplement infant formulas (IFs), mainly with polar lipid fractions of bovine MFGM and to a lesser extent with protein fractions. The aim is thus to narrow the gap between human breast milk and cow-based IFs. Despite the few attempts made to date, supplementation with MFGM proteins seems promising as MFGM lipid supplementation. A deeper understanding of MFGM proteomes should lead to better results.

Alleviation of Metabolic Endotoxemia by Milk Fat Globule Membrane: Rationale, Design, and Methods of a Double-Blind, Randomized, Controlled, Crossover Dietary Intervention in Adults with Metabolic Syndrome

BACKGROUND

Milk fat globule membrane (MFGM) is a phospholipid-rich component of dairy fat that might explain the benefits of full-fat dairy products on cardiometabolic risk. Preclinical studies support that MFGM decreases gut permeability, which could attenuate gut-derived endotoxin translocation and consequent inflammatory responses that impair cardiometabolic health.

OBJECTIVES

To describe the rationale, study design, and planned outcomes that will evaluate the efficacy of MFGM-enriched milk compared with a comparator beverage on health-promoting gut barrier functions in persons with metabolic syndrome (MetS).

METHODS

We plan a double-blind, randomized, crossover trial in which people with MetS will receive a rigorously controlled eucaloric diet for 2 wk that contains 3 daily servings of an MFGM-enriched bovine milk beverage or a comparator beverage that is formulated with nonfat dairy powder, coconut and palm oils, and soy phospholipids. Compliance will be monitored by assessing urinary para-aminobenzoic acid that is added to all test beverages. After the intervention, participants will ingest a high-fat/high-carbohydrate meal challenge to assess metabolic excursions at 30-min intervals for 3 h. Nondigestible sugar probes also will be ingested prior to collecting 24-h urine to assess region-specific gut permeability. Intervention efficacy will be determined based on circulating endotoxin (primary outcome) and glycemia (secondary outcome). Tertiary outcomes include: gut and systemic inflammatory responses, microbiota composition and SCFAs, gut permeability, and circulating insulin and incretins.

EXPECTED RESULTS

MFGM is expected to decrease circulating endotoxin and glycemia without altering body mass. These improvements are anticipated to be accompanied by decreased gut permeability, decreased intestinal and circulating biomarkers of inflammation, increased circulating incretins, and beneficial antimicrobial and prebiotic effects in the gut microbiome.

CONCLUSIONS

Demonstration of improvements in gut barrier functions that limit endotoxemia and glycemia could help to establish direct evidence that full-fat dairy lowers cardiometabolic risk, especially in people with MetS.The clinical trial associated with this article has been registered at clinicaltrials.gov (NCT03860584).

Milk fat globule membrane: the role of its various components in infant health and development

Breastfeeding confers many benefits to the breast-fed infant which are reflected by better short-term and long-term outcomes as compared to formula-fed infants. Many components of breast milk are likely to contribute to these favorable outcomes, and there has recently been focus on the milk fat globule membrane (MFGM). This fraction is a heterogenous mixture of proteins (many of them glycosylated), phospholipids, sphingolipids, gangliosides, choline, sialic acid and cholesterol which is lacking in infant formula as milk fat (which is also low in these components) is replaced by vegetable oils. Many of these components have been shown to have biological effects, and there is considerable evidence from preclinical studies and clinical trials that providing bovine MFGM results in improved outcomes, in particular with regard to infections and neurodevelopment. Since bovine MFGM is commercially available, it is possible to add it to infant formula. There are, however, considerable variations in composition among commercial sources of bovine MFGM, and as it is not known which of the individual components provide the various bioactivities, it becomes important to critically review studies to date and to delineate the mechanisms behind the activities observed. In this review, we critically examine the preclinical and clinical studies on MFGM and its components in relation to resistance to infections, cognitive development, establishment of gut microbiota and infant metabolism, and discuss possible mechanisms of action.

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.

Comparative Analysis of Milk Fat Globular Membrane (MFGM) Proteome between Saudi Arabia Camelus dromedary Safra and Wadha Breeds

Camel milk is traditionally known to have medicinal properties and many potential health benefits. Natural milk contains many soluble proteins and nanoparticles, such as a milk fat globule membrane (MFGM), a three-layered membrane covering of milk fat globule mainly composed of proteins and lipids, which plays an important role in human health. MFGM proteins account for 1%-4% of total milk proteins, and their nutritive value and distribution depends on the different breeds. The differential composition of these membrane proteins among different camel breeds has not been explored. The current study, therefore, aimed to quantitatively analyze and compare the MFGM proteome between the milk produced by the two most common Saudi camel breeds, Camelus dromedarius: Safra and Wadha. Two-dimensional difference in gel electrophoresis (2D-DIGE) and mass spectrometry analysis revealed a total of 44 MFGM proteins that were identified with a significant difference in abundance (p ≤ 0.05; fold change ≥ 1.5) between the two breeds. Thirty-one proteins were up-regulated and 13 proteins were down-regulated in the Safra breed compared to the Wadha breed. The proteins identified with an increased abundance included α-lactalbumin, lactadherin, and annexin a8, whereas the down-regulated proteins included butyrophilin subfamily 1 member a1, lactotransferrin, and vinculin. The differentially abundant proteins were analyzed by the UNIPROT system and gene ontology (GO) to reveal their associations with known biological functions and pathways. Enzyme-linked immunosorbent assay (ELISA) confirmed the 2D-DIGE findings of butyrophilin (BTN) and α-lactalbumin (α-LA) levels obtained from Safra and Wadha breeds.