Nuclear Magnetic Resonance Metabolomics Reveals Qualitative and Quantitative Differences in the Composition of Human Breast Milk and Milk Formulas

Comparison of human breast milk vs commercial formula-induced early trophic enteral nutrition during postoperative prolonged starvation in an animal model

The present study aimed to characterize the changes in macromolecular composition and structure in ileal tissue induced by postoperative prolonged starvation (PS), human breast milk feeding (HM) and commercial formula feeding (CF) for 48 and 72 h (h). Forty-two Wistar albino rats underwent an ileal transection and primary anastomosis and were then divided into six subgroups. Two groups of seven rats were food-deprived for 48 and 72 h with free access to water only in metabolic cages (48 h PS, 72 h PS). Then, two groups of seven rats received early enteral trophic nutrition (EEN) either using HM, and CF at 48 h post-operation (48 h HM, 48 h CF). The other two groups of seven rats received the same trophic enteral nutrition at 72 h post-operation (72 h HM, 72 h CF). An additional seven rats were fed normal rat chow (control), after which the ileal tissues were harvested and freeze-dried overnight. Then sample spectra were recorded by Fourier transform infrared (FTIR) spectroscopy. PS at 48 and 72 h resulted in an increase in the concentration of lipids and a decrease in the concentration of proteins. CF and HM trophic feeding induced a decrease in membrane fluidity and an increase in lipid order. Ileal tissues showed similar compositional and structural changes in lipids and proteins in the PS and CF groups after 48 and 72 h. A marked decrease in nucleic acid concentration was seen in CF at 48 h compared to HM. The human milk feeding groups did not induce any significant alterations and showed compositional and structural data similar to the controls. In conclusion, EEN application seems to be safer when introduced at 48 h rather than 72 h and time of this nutrition is crucial to maintain ileum structure and therefore immunity and well-being. HM-induced trophic nutrition is seen to protect the ileal tissue from significant alterations within lipid and protein compositions, whereas CF caused notable changes. HM is absolutely the best nutritional source for gut health in this animal model.

The Human Milk Metabolome: A Scoping Literature Review

BACKGROUND

Human milk is a complex source of nutrition and other bioactives that protects infants from disease, holding a lifetime of beneficial effects. The field of metabolomics provides a robust platform through which we can better understand human milk at a level rarely examined.

RESEARCH AIM

To Identify, describe, synthesize, and critically analyze the literature within the past 5 years related to the human milk metabolome.

METHODS

We conducted a scoping literature review and quality analysis of the recent science reflecting untargeted metabolomic approaches to examining human milk. We searched six databases using the terms "breast milk," "metabolome," "metabolite," and "human milk," Out of more than 1,069 abstracts, we screened and identified 22 articles that met our inclusion criteria.

RESULTS

We extracted data related to the study author, geographic location, research design, analyses, platform used, and results. We also extracted data related to human milk research activities, including collection protocol, infant/maternal considerations, and time. Selected studies focused on a variety of phenotypes, including maternal and infant disease. Investigators used varying approaches to evaluate the metabolome, and differing milk collection protocols were observed.

CONCLUSION

The human milk metabolome is informed by many factors-which may contribute to infant health outcomes-that have resulted in disparate milk metabolomic profiles. Standardized milk collection and storage procedures should be implemented to minimize degradation. Investigators may use our findings to develop research questions that test a targeted metabolomic approach.

Pre-analytical aspects in metabolomics of human biofluids - sample collection, handling, transport, and storage

Metabolomics is the field of omics research that offers valuable insights into the complex composition of biological samples. It has found wide application in clinical diagnostics, disease investigation, therapy prediction, monitoring of treatment efficiency, drug discovery, or in-depth analysis of sample composition. A suitable study design constitutes the fundamental requirements to ensure robust and reliable results from the study data. The study design process should include a careful selection of conditions for each experimental step, from sample collection to data analysis. The pre-analytical variability that can introduce bias to the subsequent analytical process, decrease the outcome reliability, and confuse the final results of the metabolomics research, should also be considered. Herein, we provide key information regarding the pre-analytical variables affecting the metabolomics studies of biological fluids that are the most desirable type of biological samples. Our work offers a practical review that can serve and guide metabolomics pre-analytical design. It indicates pre-analytical factors, which can introduce artificial data variation and should be identified and understood during experimental design (through literature overview or analytical experiments).

Comparing human milk macronutrients measured using analyzers based on mid-infrared spectroscopy and ultrasound and the application of machine learning in data fitting

OBJECTIVE

Fat, carbohydrates (mainly lactose) and protein in breast milk all provide indispensable benefits for the growth of newborns. The only source of nutrition in early infancy is breast milk, so the energy of breast milk is also crucial to the growth of infants. Some macronutrients composition in human breast milk varies greatly, which could affect its nutritional fulfillment to preterm infant needs. Therefore, rapid analysis of macronutrients (including lactose, fat and protein) and milk energy in breast milk is of clinical importance. This study compared the macronutrients results of a mid-infrared (MIR) analyzer and an ultrasound-based breast milk analyzer and unified the results by machine learning.

METHODS

This cross-sectional study included breastfeeding mothers aged 22-40 enrolled between November 2019 and February 2021. Breast milk samples (n = 546) were collected from 244 mothers (from Day 1 to Day 1086 postpartum). A MIR milk analyzer (BETTERREN Co., HMIR-05, SH, CHINA) and an ultrasonic milk analyzer (Honɡyanɡ Co,. HMA 3000, Hebei, CHINA) were used to determine the human milk macronutrient composition. A total of 465 samples completed the tests in both analyzers. The results of the ultrasonic method were mathematically converted using machine learning, while the Bland-Altman method was used to determine the limits of agreement (LOA) between the adjusted results of the ultrasonic method and MIR results.

RESULTS

The MIR and ultrasonic milk analyzer results were significantly different. The protein, fat, and energy determined using the MIR method were higher than those determined by the ultrasonic method, while lactose determined by the MIR method were lower (all p < 0.05). The consistency between the measured MIR and the adjusted ultrasound values was evaluated using the Bland-Altman analysis and the scatter diagram was generated to calculate the 95% LOA. After adjustments, 93.96% protein points (436 out of 465), 94.41% fat points (439 out of 465), 95.91% lactose points (446 out of 465) and 94.62% energy points (440 out of 465) were within the LOA range. The 95% LOA of protein, fat, lactose and energy were - 0.6 to 0.6 g/dl, -0.92 to 0.92 g/dl, -0.88 to 0.88 g/dl and - 40.2 to 40.4 kj/dl, respectively and clinically acceptable. The adjusted ultrasonic results were consistent with the MIR results, and LOA results were high (close to 95%).

CONCLUSIONS

While the results of the breast milk rapid analyzers using the two methods varied significantly, they could still be considered comparable after data adjustments using linear regression algorithm in machine learning. Machine learning methods can play a role in data fitting using different analyzers.

Dynamic Changes in the Human Milk Metabolome Over 25 Weeks of Lactation

Human milk (HM) provides essential nutrition for ensuring optimal infant growth and development postpartum. Metabolomics offers insight into the dynamic composition of HM. Studies have reported the impact of lactation stage, maternal genotype, and gestational age on HM metabolome. However, the majority of the studies have considered changes within the first month of lactation or sampled with large intervals. This leaves a gap in the knowledge of progressing variation in HM composition beyond the first month of lactation. The objective of this study was to investigate whether the HM metabolome from mothers with term deliveries varies beyond 1 month of lactation, during the period in which HM is considered fully mature. Human milk samples (n = 101) from 59 mothers were collected at weeks 1-2, 3-5, 7-9, and 20-25 postpartum and analyzed using 1H nuclear magnetic resonance spectroscopy. Several metabolites varied over lactation and exhibited dynamic changes between multiple time points. Higher levels of HM oligosaccharides, cis-aconitate, O-phosphocholine, O-acetylcarnitine, gluconate, and citric acid were observed in early lactation, whereas later in lactation, levels of lactose, 3-fucosyllactose, glutamine, glutamate, and short- and medium-chain fatty acids were increased. Notably, we demonstrate that the HM metabolome is dynamic during the period of maturity.

Goat Milk Foodomics. Dietary Supplementation of Sunflower Oil and Rapeseed Oil Modify Milk Amino Acid and Organic Acid Profiles in Dairy Goats

The dietary supplementation of vegetable oils is known to improve the dietary energy density as well as milk fatty acid profile; however, the impacts on the milk foodome is largely unknown. This study investigated the effect of two different sources of unsaturated fatty acids, rapeseed oil and sunflower oil, as a feeding supplement on the milk foodome from dairy goats. Nine Danish Landrace goats at 42 ± 5 days in milk were allocated to three treatment groups for 42 days with three animals per group. A control group received a basal diet made of forage and concentrate at an 85:15 ratio. On top of the basal diet, the second and third groups received rapeseed oil or sunflower oil supplements at 4% of dry matter, respectively. Goat milk was sampled on days 14, 21, and 42. The milk foodome was measured using gas chromatography–mass spectrometry and proton nuclear magnetic resonance spectroscopy. The milk levels of 2-hydroxyisovaleric acid, oxaloacetic acid, and taurine were higher in the milk from goats fed with sunflower oil compared to the control group. More glucose-1-phosphate was found in the milk from goats fed with rapeseed oil compared to the control group. Amino acids, valine and tyrosine, and 2-hydroxyisovaleric acid and oxaloacetic acid were higher in the sunflower group compared to the rapeseed group, while the milk from the rapeseed-fed goats had greater levels of ethanol and 2-oxoglutaric acid compared to the sunflower group. Thus, results show that foodomics is suitable for studying how milk chemistry changes as a function of feeding regime.

Compositional and Functional Considerations for Bovine-, Caprine- and Plant-Based Infant Formulas

Breastmilk is the optimal source of nutrition for infants. However, in circumstances where breastfeeding is not possible or feasible, infant formula provides an essential alternative to fulfil the nutritional requirements of the developing infant. Traditionally, the manufacture of infant formula has involved utilisation of bovine milk as a base ingredient, formulated with other nutrients and bioactive ingredients to closely match the composition of human breastmilk. While it is the most widely available type of formula on the market, bovine-based infant formula is not suitable for all infants, and therefore alternatives such as those based on caprine milk, soy and rice protein are becoming increasingly available. This review provides a detailed examination of the composition of infant formula prepared from bovine milk, caprine milk, soy, and rice protein sources. Available literature on nutrient bio-accessibility and aspects of protein functionality relevant to infant formula is discussed.

Development and evaluation of a holographic method for analysis of infant formula humanization based on the milk nutrient molecular dataset

A comprehensive understanding of the qualitative and quantitative similarities and distinctions between the nutrient system of human milk and infant formula is critical in developing infant formulas. However, a holographic comparison method has not been intensively developed to measure the degree of humanization of infant formulas. Consequently, discriminative biomarkers affecting the degree of humanization of infant formulas have not been extensively investigated. This study compiled a milk nutrient molecular dataset, and then presented a new method to identify the degree of humanization of infant formula. The molecular information was converted into a matrix, and then the degree of humanization was elucidated according to the matrix correlation, PCA and OPLS-DA. Compared with infant formulas 2 and 3, infant formula 1 showed the highest degree of humanization at 0.9563. Furthermore, we reported many discriminative biomarkers, such as His, Leu, and Thr, which have not been found in other studies.

The clinical impact of maternal weight on offspring health: lights and shadows in breast milk metabolome

INTRODUCTION

Pre-pregnancy overweight and obesity, depending on maternal nutrition and metabolic state, can influence fetal, neonatal and long-term offspring health, regarding cardio-metabolic, respiratory, immunological and cognitive outcomes. Thus, maternal weight can act, through mechanisms that are not full understood, on the physiology and metabolism of some fetal organs and tissues, to adapt themselves to the intrauterine environment and nutritional reserves. These effects could occur by modulating gene expression, neonatal microbiome, and through breastfeeding.

AREAS COVERED

In this paper, we investigated the potential effects of metabolites found altered in breast milk (BM) of overweight/obese mothers, through an extensive review of metabolomics studies, and the potential short- and long-term clinical effects in the offspring, especially regarding overweight, glucose homeostasis, insulin resistance, oxidative stress, infections, immune processes, and neurodevelopment.

EXPERT OPINION

Metabolomics seems the ideal tool to investigate BM variation depending on maternal or fetal/neonatal factors. In particular, BM metabolome alterations according to maternal conditions were recently pointed out in cases of gestational diabetes, preeclampsia, intrauterine growth restriction and maternal overweight/obesity. In our opinion, even if BM is the food of choice in neonatal nutrition, the deepest comprehension of its composition in overweight/obese mothers could allow targeted supplementation, to improve offspring health and metabolic homeostasis.

Detection of bovine milk adulteration in caprine milk with N-acetyl carbohydrate biomarkers by using 1H nuclear magnetic resonance spectroscopy

In a return to tradition, the popularity of caprine milk is on the rise. However, particularly in countries with developed dairy industries based on bovine milk, there is the risk of adulteration with bovine milk, which is a cheaper alternative. Thus, a rapid, robust, and simple method for the detection of bovine milk added to caprine milk is necessary, and ¹H nuclear magnetic resonance spectroscopy appears to provide a solution. A matrix of 115 pure and artificially adulterated pasteurized milk samples was prepared and used to discover biomarkers of bovine milk that are independent of chemical and biological variation caused by factors such as genetics, diet, or seasonality. Principal component analysis and orthogonal projections to latent structures discriminant analysis of pure bovine milk and pure caprine milk revealed spectral features that were assigned to the resonances of 4 molecules. Of these, the peaks corresponding to protons in the N-acetylglucosamine and N-acetylgalactosamine acetyl moieties showed significant applicability for our method. Receiver operating characteristic curve analysis was used to evaluate the performance of the peak integrals as biomarkers of adulteration. This approach was able to distinguish caprine milk adulterated with 5% of bovine milk with 84.78% accuracy and with 10% of bovine milk an excellent 95.65% accuracy. This study demonstrates that N-acetyl carbohydrates could be used as biomarkers for the detection of bovine milk in caprine milk and could help in protecting caprine milk authenticity.

The Metabolomic Analysis of Human Milk Offers Unique Insights into Potential Child Health Benefits

PURPOSE OF REVIEW

Human milk is the gold standard of infant nutrition. The milk changes throughout lactation and is tailored for the infant providing the nutrients, minerals and vitamins necessary for supporting healthy infant growth. Human milk also contains low molecular weight compounds (metabolites) possibly eliciting important bioactivity. Metabolomics is the study of these metabolites. The purpose of this review was to examine recent metabolomics studies and cohort studies on human milk to assess the impact of human milk metabolomic analyses combined with investigations of infant growth and development.

RECENT FINDINGS

The metabolite profile of human milk varies among other factors according to lactation stage, gestation at birth, and maternal genes, diet and disease state. Few studies investigate how these variations impact infant growth and development. Several time-related factors affecting human milk metabolome are potentially ubiquitous among mothers, although maternal-related factors are heavily confounded, which complicates studies of metabolite abundancies and variabilities and further possibilities of observing cause and effect in infants.