Digestion and Absorption of Milk Phospholipids in Newborns and Adults

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.

Human milk sphingomyelin: Function, metabolism, composition and mimicking

Human milk, which contains various nutrients, is the "gold standard" for infant nutrition. Healthy human milk meets all the nutritional needs of early infant development. Polar lipids mainly exist in the milk fat globule membrane, accounting for approximately 1-2% of human milk lipids; sphingomyelin (SM) accounts for approximately 21-24% of polar lipids. SM plays an important role in promoting the development of the brain and nervous system, regulating intestinal flora, and improving skin barriers. Though SM could be synthesized de novo, SM nutrition from dietary is also important for infants. The content and composition of SM in human milk has been reported, however, the molecular mechanisms of nutritional functions of SM for infants required further research. This review summarizes the functional mechanisms, metabolic pathways, and compositional, influencing factors, and mimicking of SM in human milk, and highlights the challenges of improving maternal and infant early/long-term nutrition.

Advances in the composition, efficacy, and mimicking of human milk phospholipids

Phospholipids are the essential components of human milk, contributing to the enhancement of cognitive development, regulation of immune functions, and mitigation of elevated cholesterol levels. Infant formulas supplemented with phospholipids can change the composition, content, and globule membrane structure of milk lipids, improving their digestive properties and nutritional value. However, mimicking phospholipids in infant formulas is currently limited, and the supplemented standards of phospholipid species and amounts in infant formulas are unknown. Consequently, there is a significant difference between the phospholipids in infant formulas and those in human milk. This article reviews the recent progress in human milk phospholipid research, aiming to describe the composition, content, and positive effects of human milk phospholipids, as well as summarises the dietary sources of phospholipid supplementation and the current state of human milk phospholipid mimicking in infant formulas. This review provides clear directions for research on mimicking human milk phospholipids and evaluating the nutritional functions of phospholipids in infants.

Intestinal absorption of sphingosine: new insights on generated ceramide species using stable isotope tracing in vitro

Dietary sphingomyelin (SM) has been reported to favorably modulate postprandial lipemia. Mechanisms underlying these beneficial effects on cardiovascular risk markers are not fully elucidated. Rodent studies showed that tritiated SM was hydrolyzed in the intestinal lumen into ceramides (Cer) and further to sphingosine (SPH) and fatty acids (FA) that were absorbed by the intestine. Our objective was to investigate the uptake and metabolism of SPH and/or tricosanoic acid (C23:0), the main FA of milk SM, as well as lipid secretion in Caco-2/TC7 cells cultured on semipermeable inserts. Mixed micelles (MM) consisting of different digested lipids and taurocholate were prepared without or with SPH, SPH and C23:0 (SPH+C23:0), or C23:0. Triglycerides (TG) were quantified in the basolateral medium, and sphingolipids were analyzed by tandem mass spectrometry. TG secretion increased 11-fold in all MM-incubated cells compared with lipid-free medium. Apical supply of SPH-enriched MM led to increased concentrations of total Cer in cells, and coaddition of C23:0 in SPH-enriched MM led to a preferential increase of C23:0 Cer and C23:0 SM. Complementary experiments using deuterated SPH demonstrated that SPH-d9 was partly converted to sphingosine-1-phosphate-d9, Cer-d9, and SM-d9 within cells incubated with SPH-enriched MM. A few Cer-d9 (2% of added SPH-d9) was recovered in the basolateral medium of (MM+SPH)-incubated cells, especially C23:0 Cer-d9 in (MM+SPH+C23:0)-enriched cells. In conclusion, present results indicate that MM enriched with (SPH+C23:0), such as found in postprandial micelles formed after milk SM ingestion, directly impacts sphingolipid endogenous metabolism in enterocytes, resulting in the secretion of TG-rich particles enriched with C23:0 Cer.

Is choline deficiency an unrecognized factor in necrotizing enterocolitis of preterm infants?

We undertook this review to determine if it is plausible that choline or phosphatidylcholine (PC) deficiency is a factor in necrotizing enterocolitis (NEC) after two clinical trials found a dramatic and unexpected reduction in NEC in an experimental group provided higher PC compared to a control group. Sources and amounts of choline/PC for preterm infants are compared to the choline status of preterm infants at birth and following conventional nutritional management. The roles of choline/PC in intestinal structure, mucus, mesenteric blood flow, and the cholinergic anti-inflammatory system are summarized. Low choline/PC status is linked to prematurity/immaturity, parenteral and enteral feeding, microbial dysbiosis and hypoxia/ischemia, factors long associated with the risk of developing NEC. We conclude that low choline status exists in preterm infants provided conventional parenteral and enteral nutritional management, and that it is plausible low choline/PC status adversely affects intestinal function to set up the vicious cycle of inflammation, loss of intestinal barrier function and worsening tissue hypoxia that occurs with NEC. In conclusion, this review supports the need for randomized clinical trials to test the hypothesis that additional choline or PC provided parenterally or enterally can reduce the incidence of NEC in preterm infants. IMPACT STATEMENT: Low choline status in preterm infants who are managed by conventional nutrition is plausibly linked to the risk of developing necrotizing enterocolitis.

RM, Acra SA, Townsend SD, Yan F. A human milk oligosaccharide prevents intestinal inflammation in adulthood via modulating gut microbial metabolism

Observational evidence suggests that human milk oligosaccharides (HMOs) promote the growth of commensal bacteria in early life and adulthood. However, the mechanisms by which HMOs benefit health through modulation of gut microbial homeostasis remain largely unknown. 2'-fucosyllactose (2'-FL) is the most abundant oligosaccharide in human milk and contributes to the essential health benefits associated with human milk consumption. Here, we investigated how 2'-FL prevents colitis in adulthood through its effects on the gut microbial community. We found that the gut microbiota from adult mice that consumed 2'-FL exhibited an increase in abundance of several health-associated genera, including Bifidobacterium and Lactobacillus. The 2'-FL-modulated gut microbial community exerted preventive effects on colitis in adult mice. By using Bifidobacterium infantis as a 2'-FL-consuming bacterial model, exploratory metabolomics revealed novel 2'-FL-enriched secretory metabolites by Bifidobacterium infantis, including pantothenol. Importantly, pantothenate significantly protected the intestinal barrier against oxidative stress and mitigated colitis in adult mice. Furthermore, microbial metabolic pathway analysis identified 26 dysregulated metabolic pathways in fecal microbiota from patients with ulcerative colitis, which were significantly regulated by 2'-FL treatment in adult mice, indicating that 2'-FL has the potential to rectify dysregulated microbial metabolism in colitis. These findings support the contribution of the 2'-FL-shaped gut microbial community and bacterial metabolite production to the protection of intestinal integrity and prevention of intestinal inflammation in adulthood.IMPORTANCEAt present, neither basic research nor clinical studies have revealed the exact biological functions or mechanisms of action of individual oligosaccharides during development or in adulthood. Thus, it remains largely unknown whether human milk oligosaccharides could serve as effective therapeutics for gastrointestinal-related diseases. Results from the present study uncover 2'-FL-driven alterations in bacterial metabolism and identify novel B. infantis-secreted metabolites following the consumption of 2'-FL, including pantothenol. This work further demonstrates a previously unrecognized role of pantothenate in significantly protecting the intestinal barrier against oxidative stress and mitigating colitis in adult mice. Remarkably, 2'-FL-enhanced bacterial metabolic pathways are found to be dysregulated in the fecal microbiota of ulcerative colitis patients. These novel metabolic pathways underlying the bioactivities of 2'-FL may lay a foundation for applying individual oligosaccharides for prophylactic intervention for diseases associated with impaired intestinal homeostasis.

Preventative Effects of Milk Fat Globule Membrane Ingredients on DSS-Induced Mucosal Injury in Intestinal Epithelial Cells

The goblet cells of the gastrointestinal tract (GIT) produce glycoproteins called mucins that form a protective barrier from digestive contents and external stimuli. Recent evidence suggests that the milk fat globule membrane (MFGM) and its milk phospholipid component (MPL) can benefit the GIT through improving barrier function. Our objective was to compare the effects of two digested MFGM ingredients with or without dextran sodium sulfate (DSS)-induced barrier stress on mucin proteins. Co-cultured Caco-2/HT29-MTX intestinal cells were treated with in vitro digests of 2%, 5%, and 10% (w/v) MFGM or MPL alone for 6 h or followed by challenge with 2.5% DSS (6 h). Transepithelial electrical resistance and fluorescein isothiocyanate (FITC)-dextran (FD4) permeability measurements were used to measure changes in barrier integrity. Mucin characterization was performed using a combination of slot blotting techniques for secreted (MUC5AC, MUC2) and transmembrane (MUC3A, MUC1) mucins, scanning electron microscopy (SEM), and periodic acid Schiff (PAS)/Alcian blue staining. Digested MFGM and MPL prevented a DSS-induced reduction in secreted mucins, which corresponded to the prevention of DSS-induced increases in FD4 permeability. SEM and PAS/Alcian blue staining showed similar visual trends for secreted mucin production. A predictive bioinformatic approach was also used to identify potential KEGG pathways involved in MFGM-mediated mucosal maintenance under colitis conditions. This preliminary in silico evidence, combined with our in vitro findings, suggests the role of MFGM in inducing repair and maintenance of the mucosal barrier.

Environmental chemical TCPOBOP exposure alters milk liposomes and offspring growth trajectories in mice

Exposure to environmental endocrine disruptors (EEDs) has become a global health concern, and EEDs are known to be potent inducers of constitutive androstane receptor (CAR). 1,4-bis [2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP, hereafter abbreviated as TC), a specific ligand for CAR, has been considered as a potential EED. Here, we analyzed the effect of TC exposure to female mice on the histological morphology of their alveoli in the basic unit of lactation. We quantified differences in the milk metabolome of the control and TC-exposed group while assessing the correlations between metabolites and neonatal growth. Mammary histological results showed that TC exposure inhibited alveolar development. Based on the milk metabolomic data, we identified a total of 1505 differential metabolites in both the positive and negative ion mode, which indicated that TC exposure affected milk composition. As expected, the differential metabolites were significantly enriched in the drug metabolism pathway. Further analyses revealed that differential metabolites were significantly enriched in multiple lipid metabolic pathways, such as fatty acid biosynthesis, suggesting that most differential metabolites were concentrated in lipids. Simultaneously, a quantitative analysis showed that TC exposure led to a decrease in the relative abundance of total milk lipids, affecting the proportion of some lipid subclasses. Notably, a portion of lipid metabolites were associated with neonatal growth. Taken together, these findings suggest that TC exposure may affect milk lipidomes, resulting in the inability of mothers to provide adequate nutrients, ultimately affecting the growth and health of their offspring.

In Vivo Monitoring of Glycerolipid Metabolism in Animal Nutrition Biomodel-Fed Smart-Farm Eggs

Although many studies have examined the biochemical metabolic pathways by which an egg (egg yolk) lowers blood lipid levels, data on the molecular biological mechanisms that regulate and induce the partitioning of hepatic glycerolipids are missing. The aim of this study was to investigate in vivo monitoring in four study groups using an animal nutrition biomodel fitted with a jugular-vein cannula after egg yolk intake: CON (control group, oral administration of 1.0 g of saline), T1 (oral administration of 1.0 g of pork belly fat), T2 (oral administration of 1.0 g of smart-farm egg yolk), and T3 (oral administration of T1 and T2 alternately every week). The eggs induced significant and reciprocal changes in incorporating 14C lipids into the total glycerolipids and releasing 14CO2, thereby regulating esterification and accelerating oxidation in vivo. The eggs increased phospholipid secretion from the liver into the blood and decreased triacylglycerol secretion by regulating the multiple cleavage of fatty acyl-CoA moieties' fluxes. In conclusion, the results of the current study reveal the novel fact that eggs can lower blood lipids by lowering triacylglycerol secretion in the biochemical metabolic pathway of hepatic glycerolipid partitioning while simultaneously increasing phospholipid secretion and 14CO2 emission.

Gut-brain communication mediates the impact of dietary lipids on cognitive capacity

Cognitive impairment, as a prevalent symptom of nervous system disorders, poses one of the most challenging aspects in the management of brain diseases. Lipids present in the cell membranes of all neurons within the brain and dietary lipids can regulate the cognition and memory function. In recent years, the advancements in gut microbiome research have enabled the exploration of dietary lipids targeting the gut-brain axis as a strategy for regulating cognition. This present review provides an in-depth overview of how lipids modulate cognition via the gut-brain axis depending on metabolic, immune, neural and endocrine pathways. It also comprehensively analyzes the effects of diverse lipids on the gut microbiota and intestinal barrier function, thereby affecting the central nervous system and cognitive capacity. Moreover, comparative analysis of the positive and negative effects is presented between beneficial and detrimental lipids. The former encompass monounsaturated fatty acids, short-chain fatty acids, omega-3 polyunsaturated fatty acids, phospholipids, phytosterols, fungal sterols and bioactive lipid-soluble vitamins, as well as lipid-derived gut metabolites, whereas the latter (detrimental lipids) include medium- or long-chain fatty acids, excessive proportions of n-6 polyunsaturated fatty acids, industrial trans fatty acids, and zoosterols. To sum up, the focus of this review is on how gut-brain communication mediates the impact of dietary lipids on cognitive capacity, providing a novel theoretical foundation for promoting brain cognitive health and scientific lipid consumption patterns.

3-Monochloropropane-1,2-diol reduced bioaccessibility of sn-2 palmitate via binding with pancreatic lipase in infant formula during gastrointestinal digestion

Infant formula contains 3-monochloropropane-1,2-diol esters (3-MCPDE), which are formed during the deodorization step of vegetable oil refining. The European Food Safety Authority stated that 3-MCPDE can be hydrolyzed in the gastrointestinal tract to free-form 3-monochloropropane-1,2-diol (3-MCPD), which has potential toxicity and can be rapidly absorbed. Evaluating the effect of 3-MCPD on nutrition absorption is a prerequisite for establishing effective management strategies. A total of 66 crucial lipid molecules associated with 3-MCPD were identified based on debiased sparse partial correlation analysis. 3-MCPD affected triglyceride hydrolyzation and increased the concentration of undigested sn-2 palmitate (9.57 to 17.06 mg kg-1). 3-Monochloropropane-1,2-diol reduced the bioaccessibility of fatty acids, and more short- (31.42 to 58.02 mg kg-1) and medium-chain fatty acids (17.03 to 26.43 mg kg-1) remained unabsorbed. Lipidomic profiles of infant formula models spiked with different 3-MCPDE levels were investigated, and the results were consistent with the experiments with the commercial formula indicating lipid alteration was mainly affected by the digestive 3-MCPD. The formation of 3-MCPD ester-pancreatic lipase with the binding energy of -4.9 kcal mol-1 was more stable than triglyceride-pancreatic lipase (-4.0 kcal mol-1), affecting triglyceride hydrolyzation. 3-Monochloropropane-1,2-diol was bound to Glu13 and Asp331 residues of the pancreatic lipase via hydrogen bonds, which resulted in a conformational change of pancreatic lipase and spatial shielding effect. The existence of the spatial-shielding effect reduced the accessibility of pancreatic lipase and further affected triglyceride hydrolyzation. These findings indicated that 3-MCPD obstructed nutrient acquisition and laid the foundation for the subsequent nutrition enhancement design.

Role of sphingosine 1-phosphate (S1P) in sepsis-associated intestinal injury

Sphingosine-1-phosphate (S1P) is a widespread lipid signaling molecule that binds to five sphingosine-1-phosphate receptors (S1PRs) to regulate downstream signaling pathways. Sepsis can cause intestinal injury and intestinal injury can aggravate sepsis. Thus, intestinal injury and sepsis are mutually interdependent. S1P is more abundant in intestinal tissues as compared to other tissues, exerts anti-inflammatory effects, promotes immune cell trafficking, and protects the intestinal barrier. Despite the clinical importance of S1P in inflammation, with a very well-defined mechanism in inflammatory bowel disease, their role in sepsis-induced intestinal injury has been relatively unexplored. In addition to regulating lymphocyte exit, the S1P-S1PR pathway has been implicated in the gut microbiota, intestinal epithelial cells (IECs), and immune cells in the lamina propria. This review mainly elaborates on the physiological role of S1P in sepsis, focusing on intestinal injury. We introduce the generation and metabolism of S1P, emphasize the maintenance of intestinal barrier homeostasis in sepsis, and the protective effect of S1P in the intestine. We also review the link between sepsis-induced intestinal injury and S1P-S1PRs signaling, as well as the underlying mechanisms of action. Finally, we discuss how S1PRs affect intestinal function and become targets for future drug development to improve the translational capacity of preclinical studies to the clinic.

Donkey Colostrum and Milk: How Dietary Probiotics Can Affect Metabolomic Profile, Alkaline Sphingomyelinase and Alkaline Phosphatase Activity

Positive results on animal health, feed efficiency, and milk's nutritional content have been obtained after oral administration of probiotics. The aim of the present study was therefore to evaluate the effect of dietary supplementation with high numbers of multispecies probiotic formulations on the milk metabolomic profiles of alkaline sphingomyelinase (alk-SMase) and alkaline phosphatase (ALP) in donkeys. Twenty animals were randomly allocated to receive either a normal diet (group B) or a supplemented diet (group A). Colostrum and milk samples were obtained within 48 h, at 15 days (supplementation start), and at 45 days after parturition. Different metabolomic profiles were observed between colostrum and milk, as were the concentrations of 12 metabolites that changed following 30 days of probiotic supplementation. Alk-SMase activity was found to be higher in donkey colostrum (vs. milk at 15 days); this enzyme, together with ALP, increased in milk after 30 days of probiotic supplementation. The results of the present study provide new insight into the complex changes in donkey colostrum and milk composition in the first 45 days of lactation and how the milk metabolome can be modulated by probiotic supplementation.

Development of a fast and robust liquid chromatography-mass spectrometry-based metabolomics analysis method for neonatal dried blood spots

Dried blood spot (DBS) samples have been widely used in many fields including newborn screening, with the advantages in transportation, storage and non-invasiveness. The DBS metabolomics research of neonatal congenital diseases will greatly expand the understanding of the disease. In this study, we developed a liquid chromatography-mass spectrometry-based method for neonatal metabolomics analysis of DBS. The influences of blood volume and chromatographic effects on the filter paper on metabolite levels were studied. The levels of 11.11 % metabolites were different between 75 μL and 35 μL of blood volumes used for DBS preparation. Chromatographic effects on the filter paper occurred in DBS prepared with 75 μL whole blood and 6.67 % metabolites had different MS responses when central disks were compared with outer disks. The DBS storage stability study showed that compared with - 80 °C storage, storing at 4 °C for 1 year had obvious influences on more than half metabolites. Storing at 4 °C and - 20 °C for short term (< 14 days) and - 20 °C for longer term (1 year) had less influences on amino acids, acyl-carnitines and sphingomyelins, but greater influences on partial phospholipids. Method validation showed that this method has a good repeatability, intra-day and inter-day precision and linearity. Finally, this method was applied to investigate metabolic disruptions of congenital hypothyroidism (CH), metabolic changes of CH newborns were mainly involved in amino acid metabolism and lipid metabolism.

Milk fat globule membrane plus milk fat increase docosahexaenoic acid availability in infant formulas

PURPOSE

Milk fat globule membrane (MFGM) has components with emulsifier properties that could affect the provision of substrates to the brain. We evaluated the effects of MFGM plus milk fat addition to infant formulas on docosahexaenoic acid (DHA) availability and gut development.

METHODS

In Experiment 1, suckling piglets were divided into 3 groups: Group L1 (n = 8): fed with a vegetal fat formula with palm oil; L2 (n = 8): canola oil formula and L3 (n = 8): milk fat + canola oil + 1% Lacprodan (3% MFGM of total protein content). In Experiment 2, Group L4 (n = 7): fed with canola oil + 1% Lacprodan (3% MFGM) and Group L5 (n = 5): milk fat + canola oil + 2% Lacprodan (6% MFGM). All formulas contained 0.2% DHA and 0.2% arachidonic acid.

RESULTS

In Experiment 1, DHA was similar among the groups in both total fatty acids and plasma phospholipids (PL). However, 3% MFGM (L3) increased significantly the proportion of DHA and LC-PUFA n-3 in liver total fatty acids, jejunum, and also in jejunum PL respect to the other formulas. There were no changes in gut histology, cell proliferation, apoptosis, or brain DHA content. In Experiment 2, higher MFGM dose was used. Then, higher DHA was not only found in peripheral tissues of 6% MFGM (L5) piglets but also in plasma PL, while a similar trend was observed in cortex PL (p = 0.123).

CONCLUSION

In conclusion, MFGM plus milk fat may increase DHA availability of infant formulas which could contribute to their beneficial health effects.

Transcriptome analysis of intestine from alk-SMase knockout mice reveals the effect of alk-SMase

Objective

Intestinal alkaline sphingomyelinase (alk-SMase) generates ceramide and inactivates platelet-activating factor associated with digestion and inhibition of cancer. There is few study to analyze the correlated function and characterize the genes related to alk-SMase comprehensively. We characterised transcriptome landscapes of intestine tissues from alk-SMase knockout (KO) mice aiming to identify novel associated genes and research targets.

Methods

We performed the high-resolution RNA sequencing of alk-SMase KO mice and compared them to wild type (WT) mice. Differentially expressed genes (DEGs) for the training group were screened. Functional enrichment analysis of the DEGs between KO mice and WT mice was implemented using the Database for Annotation, Visualization and Integrated Discovery (DAVID). An integrated protein–protein interaction (PPI) and Kyoto Encyclopedia of Genes and Genomes (KEGG) network was chose to study the relationship of differentially expressed gene. Moreover, quantitative real-time polymerase chain reaction (qPCR) was further used to validate the accuracy of RNA-seq technology.

Results

Our RNA-seq data found 97 differentially expressed mRNAs between the WT mice and alk-SMase gene NPP7 KO mice, in which 32 were significantly up-regulated and 65 were down-regulated, including protein coding genes, non-coding RNAs. Notably, the results of gene ontology functional enrichment analysis indicated that DEGs were functionally associated with the immune response, regulation of cell proliferation and development related terms. Additionally, an integrated network analysis was shown that some modules was significantly related to alk-SMase and with accordance of previously results. We chose 6 of these genes randomly were validated the accuracy of RNA-seq technology using qPCR and 2 genes showed difference significantly (P < 0.05).

Conclusions

We investigated the potential biological significant of alk-SMase with high resolution genome-wide transcriptome of alk-SMase knockout mice. The results revealed new insight into the functional modules related to alk-SMase was involved in the intestinal related diseases.

The nutritional functions of dietary sphingomyelin and its applications in food

Sphingolipids are common structural components of cell membranes and are crucial for cell functions in physiological and pathophysiological conditions. Sphingomyelin and its metabolites, such as sphingoid bases, ceramide, ceramide-1-phosphate, and sphingosine-1-phosphate, play signaling roles in the regulation of human health. The diverse structures of sphingolipids elicit various functions in cellular membranes and signal transduction, which may affect cell growth, differentiation, apoptosis, and maintain biological activities. As nutrients, dietary sphingomyelin and its metabolites have wide applications in the food and pharmaceutical industry. In this review, we summarized the distribution, classifications, structures, digestion, absorption and metabolic pathways of sphingolipids, and discussed the nutritional functioning of sphingomyelin in chronic metabolic diseases. The possible implications of dietary sphingomyelin in the modern food preparations including dairy products and infant formula, skin improvement, delivery system and oil organogels are also evaluated. The production of endogenous sphingomyelin is linked to pathological changes in obesity, diabetes, and atherosclerosis. However, dietary supplementations of sphingomyelin and its metabolites have been shown to maintain cholesterol homeostasis and lipid metabolism, and to prevent or treat these diseases. This seemly paradoxical phenomenon shows that dietary sphingomyelin and its metabolites are candidates for food additives and functional food development for the prevention and treatment of chronic metabolic diseases in humans.

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.

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.

Assessment of Seasonal and Diurnal Variations of Alkaline Phosphatase Activity in Pasteurized Milk

The present study was conducted to detect the concentration levels of ALP (alkaline phosphatase) in pasteurized milk and determine whether the pasteurization was successful or not, according to WHO Directives, which clearly state that the ALP (alkaline phosphatase) substance in pasteurized milk must be totally inactivated, by implementing a newly developed method. The study, additionally, focused on repeatability, stability of results, the effect of the environmental temperature, the effect of the different origins of the milk and convenience with respect to performance characteristics of three methods for the detection of ALP. The milk samples were collected from different areas of Greece during February 2016–February 2018 and May 2019–January 2020. The novel enzymatic biochemical method, named the “AP test”, showed superior characteristics for a diversity of materials such as milk, whey, cheese and butter in comparison to the other two methods that were used for screening and quantitative estimation of the concentration of ALP in samples.

Phospholipid composition and fat globule structure II: Comparison of mammalian milk from five different species

We compared phospholipids (PLs) content, their molecular species, and milk fat globules size and microstructure in the milk of five mammalian species, including human, cow, goat, yak, and donkey. The absolute quantification of major PLs was determined using ³¹P NMR and their fatty acid composition with GC. The molecular species of PLs were analysed using LC-MS where a total of 9 PL species, including one sphingomyelin (SM), six glycerophospholipid (GPL), and two lysoglycerophospholipids (lyso-GPLs), were identified. PLs profile shows an obvious difference among the species, with human milk showing higher SM content and more unsaturated fatty acyls than other mammalian milk. The mammalian milk show a similar core-membrane lipid structure but obvious different size distribution. These data provide a basis for better construction of infant formulas to provide PLs requirements and a similar milk fat globule structure for infants.

FT-MIR Analysis of Water-Soluble Extracts during the Ripening of Sheep Milk Cheese with Different Phospholipid Content

The purpose of this work was to study the suitability of the water-soluble extracts (WSE) of semi-hard sheep milk cheese for analysis by diffuse reflectance Fourier transform mid-infrared spectroscopy (FT-MIR) and the development of classification models using discriminant analysis and based on cheese age or phospholipid content. WSE was extracted from three types of sheep milk cheeses (full-fat, reduced-fat and reduced-fat fortified with lyophilized sweet sheep buttermilk) at various stages of ripening from six to 168 days and lyophilized. The first model used 1854–1381 and 1192–760 cm−1 regions of the first-derivative spectra and successfully differentiated samples of different age, based on changes in the water-soluble products of ripening biochemical events. The second model used the phospholipid absorbance spectral regions (3012–2851, 1854–1611 and 1192–909 cm−1) to successfully discriminate cheeses of markedly different phospholipid content. Cheese WSE was found suitable for FT-MIR analysis. According to the results, a fast and simple method to monitor cheese ripening based on water-soluble substances has been developed. Additionally, the results indicated that a considerable amount of phospholipids migrates to the cheese WSE and that FT-MIR can be a useful tool for their assessment.