The role of human milk fats in shaping neonatal development and the early life gut microbiota

Bioactive compounds in human milk

PURPOSE OF REVIEW

Human milk is the optimal food choice for infants. Reviewing the latest advances in research about human milk compounds and their effect on health helps understand the benefits of breastfeeding and improves knowledge of key bioactive nutrients that can be used to improve feeding during infancy, with short and long-time effects on health.

RECENT FINDINGS

In the last years, it has been described how bioactive compounds such as Human milk oligosaccharides, hormones, lipids, cellular components and microbes play an important role in the infants' health, reducing the risk of infectious, metabolic and autoimmune diseases. The mechanisms of transmission from the mother to the infant of these bioactive compounds are not always well described, but there are several lines of research to understand the biological mechanisms of these beneficial effects.

SUMMARY

These findings may help improve research in maternal and infant interventions, the modifiable factors that are able to modulate human milk composition. They may help to improve the development of infant formulas and enhance nutritional plans. Also, human milk bioactive compounds identification and isolation may describe new ways of supplementation.

Human milk variation is shaped by maternal genetics and impacts the infant gut microbiome

Human milk is a complex mix of nutritional and bioactive components that provide complete nourishment for the infant. However, we lack a systematic knowledge of the factors shaping milk composition and how milk variation influences infant health. Here, we characterize relationships between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome in up to 310 exclusively breastfeeding mother-infant pairs. We identified 482 genetic loci associated with milk gene expression unique to the lactating mammary gland and link these loci to breast cancer risk and human milk oligosaccharide concentration. Integrative analyses uncovered connections between milk gene expression and infant gut microbiome, including an association between the expression of inflammation-related genes with milk interleukin-6 (IL-6) concentration and the abundance of Bifidobacterium and Escherichia in the infant gut. Our results show how an improved understanding of the genetics and genomics of human milk connects lactation biology with maternal and infant health.

New insights into dairy management and the prevention and treatment of osteoporosis: The shift from single nutrient to dairy matrix effects-A review

Dairy is recognized as a good source of calcium, which is important for preventing osteoporosis. However, the relationship between milk and bone health is more complex than just calcium supplementation. It is unwise to focus solely on observing the effects of a single nutrient. Lactose, proteins, and vitamins in milk, as well as fatty acids, oligosaccharides, and exosomes, all work together with calcium to enhance its bioavailability and utilization efficiency through various mechanisms. We evaluate the roles of dairy nutrients and active ingredients in maintaining bone homeostasis from the perspective of the dairy matrix effects. Special attention is given to threshold effects, synergistic effects, and associations with the gut-bone axis. We also summarize the associations between probiotic/prebiotic milk, low-fat/high-fat milk, lactose-free milk, and fortified milk with a reduced risk of osteoporosis and discuss the potential benefits and controversies of these dairy products. Moreover, we examine the role of dairy products in increasing peak bone mass during adolescence and reducing bone loss in old age. It provides a theoretical reference for the use of dairy products in the accurate prevention and management of osteoporosis and related chronic diseases and offers personalized dietary recommendations for bone health in different populations.

Milk Fat Globules: 2024 Updates

Milk fat globules (MFGs) are a remarkable example of nature's ingenuity. Human milk (HM) carries contains 3-5% fat, 0.8-0.9% protein, 6.9-7.2% carbohydrate calculated as lactose, and 0.2% mineral constituents. Most of these nutrients are carried in these MFGs, which are composed of an energy-rich triacylglycerol (TAG) core surrounded by a triple membrane structure. The membrane contains polar lipids, specialized proteins, glycoproteins, and cholesterol. Each of these bioactive components serves important nutritional, immunological, neurological, and digestive functions. These MFGs are designed to release energy rapidly in the upper gastrointestinal tract and then persist for some time in the gut lumen so that the protective bioactive molecules are conveyed to the colon. These properties may shape the microbial colonization and innate immune properties of the developing gastrointestinal tract. Milk fat globules in milk from humans and ruminants may resemble in structure but there are considerable differences in size, profile, composition, and specific constituents. There are possibilities to not only enhance the nutritional composition in a goal-oriented fashion to correct specific deficiencies in the infant but also to use these fat globules as a nutraceutical in infants who require specific treatments. To mention a few, there might be possibilities in enhancing neurodevelopment, in defense against gastrointestinal and respiratory tract infections, improving insulin sensitivity, treating chronic inflammation, and altering plasma lipids. This review provides an overview of the composition, structure, and biological activities of the various components of the MFGs. We have assimilated research findings from our own laboratory with an extensive review of the literature utilizing key terms in multiple databases including PubMed, EMBASE, and Science Direct. To avoid bias in the identification of studies, keywords were short-listed a priori from anecdotal experience and PubMed's Medical Subject Heading (MeSH) thesaurus.

Bifidobacterium infantis associates with T cell immunity in human infants and is sufficient to enhance antigen-specific T cells in mice

Bacille Calmette-Guerin (BCG) vaccine can elicit good TH1 responses in neonates. We hypothesized that the pioneer gut microbiota affects vaccine T cell responses. Infants who are HIV exposed but uninfected (iHEU) display an altered immunity to vaccination. BCG-specific immune responses were analyzed at 7 weeks of age in iHEU, and responses were categorized as high or low. Bifidobacterium longum subsp. infantis was enriched in the stools of high responders, while Bacteroides thetaiotaomicron was enriched in low responders at time of BCG vaccination. Neonatal germ-free or SPF mice orally gavaged with live B. infantis exhibited significantly higher BCG-specific T cells compared with pups gavaged with B. thetaiotaomicron. B. infantis and B. thetaiotaomicron differentially affected stool metabolome and colonic transcriptome. Human colonic epithelial cells stimulated with B. infantis induced a unique gene expression profile versus B. thetaiotaomicron. We thus identified a causal role of B. infantis in early-life antigen-specific immunity.