Pre-, pro-, syn-, and Postbiotics in Infant Formulas: What Are the Immune Benefits for Infants?

Comparative analysis of pectin and prebiotics on human microbiota modulation in early life stages and adults

The gut microbiota is essential in human health, influencing various physiological processes ranging from digestion and metabolism to immune function and mental health. Dietary fiber pectins and prebiotics have emerged as key modulators of gut microbiota composition and function, offering potential therapeutic implications for promoting gut health and preventing intestinal inflammatory diseases. In this review, we explore the modulation of gut microbiota by dietary fiber pectins and prebiotics in infants and adults. We begin with an overview of the gut microbiota composition and function in different age groups, highlighting the factors in shaping microbial communities in both age groups, especially the effect of diet. We then delve into the impact of dietary fiber pectins and prebiotics on gut microbiota composition and function, examining their effects on digestive health, intestinal barrier integrity, immune function, metabolic health, and mental health across different life stages. We further compare how aging affects the gut function and immune system, and we discuss the main health outcomes associated with dietary fiber intake and prebiotics, including the impact on digestive health, improvement in immune function, improvement in cholesterol and glucose metabolism, weight management, mental health, and prevention of diseases. Finally, we highlight the challenges and future directions for research. By advancing the understanding of gut microbiota dynamics and translating scientific insights into clinical practice, it could harness the full potential of dietary fiber pectins and prebiotics to optimize gut health, improve overall well-being across the lifespan, and increase longevity.

Human Breast Milk: The Role of Its Microbiota and Metabolites in Infant Health

This review explores the role of microorganisms and metabolites in human breast milk and their impact on neonatal health. Breast milk serves as both a primary source of nutrition for newborns and contributes to the development and maturation of the digestive, immunological, and neurological systems. It has the potential to reduce the risks of infections, allergies, and asthma. As our understanding of the properties of human milk advances, there is growing interest in incorporating its benefits into personalized infant nutrition strategies, particularly in situations in which breastfeeding is not an option. Future infant formula products are expected to emulate the composition and advantages of human milk, aligning with an evolving understanding of infant nutrition. The long-term health implications of human milk are still under investigation.

Evaluation of Safety and Beneficial Health Effects of the Human-Milk Strain Bifidobacterium breve DSM32583: An Infant Pilot Trial

Human milk promotes the growth of bifidobacteria in the infant gut. Adding bifidobacterial species to infant formula may contribute to increasing their presence in the gut of formula-fed infants. Therefore, the safety and anti-infectious effects of Bifidobacterium breve DSM32583, a breast milk isolate, were assessed in a pilot trial involving 3-month-old infants. The infants were randomly assigned to either the probiotic (PG) or the control (CG) groups. All the infants consumed the same formula, although it was supplemented with the strain (1 × 107 cfu/g of formula) in the PG. Overall, 160 infants (80 per group) finished the intervention. Infants in CG gained more weight compared to PG (p < 0.05), but the weights for age Z-scores at 6 months were within the normal distribution for this age group. The rates of infections affecting the gastrointestinal and respiratory tracts and antibiotic therapy were significantly lower in the PG. The bifidobacterial population and the level of short-chain fatty acids were higher (p < 0.05) in the fecal samples of PG infants. No adverse events related to formula consumption were observed. In conclusion, the administration of an infant formula with B. breve DSM32583 was safe and exerted potential beneficial effects on gut health.

Iron Fortification and Inulin Supplementation in Early Infancy: Evaluating the Impact on Iron Metabolism and Trace Mineral Status in a Piglet Model

Background

Infant formula in the United States contains abundant iron, raising health concerns about excess iron intake in early infancy.

Objectives

Using a piglet model, we explored the impact of high iron fortification and prebiotic or synbiotic supplementation on iron homeostasis and trace mineral bioavailability.

Methods

Twenty-four piglets were stratified and randomly assigned to treatments on postnatal day 2. Piglets were individually housed and received an iron-adequate milk diet (AI), a high-iron milk diet (HI), HI supplemented with 5% inulin (HI with a prebiotic [HIP]), or HIP with an oral gavage of Ligilactobacillus agilis YZ050, an inulin-fermenting strain, every third day (HI with synbiotic [HIS]). Milk was provided in 14 meals daily, mimicking formula feeding in infants. Fecal consistency score and body weight were recorded daily or every other day. Blood and feces were sampled weekly, and tissues collected on postnatal day 29. Data were analyzed using mixed model analysis of variance with repeated measures whenever necessary.

Results

Diet did not affect growth. HI increased hemoglobin, hematocrit, and serum iron compared to AI. Despite marginal adequacy, AI upregulated iron transporter genes and maintained satisfactory iron status in most pigs. HI upregulated hepcidin gene expression in liver, caused pronounced tissue iron deposition, and markedly increased colonic and fecal iron. Inulin supplementation, regardless of L. agilis YZ050, not only attenuated hepatic iron overload but also decreased colonic and fecal iron without altering pH or the expression of iron regulatory genes. HI lowered zinc (Zn) and copper (Cu) in the duodenum and liver compared to AI, whereas HIP and HIS further decreased Zn and Cu in the liver and diminished colonic and fecal trace minerals.

Conclusions

Early-infancy excessive iron fortification causes iron overload and compromises Zn and Cu absorption. Inulin decreases trace mineral absorption likely by enhancing gut peristalsis and stool frequency.

Microbiome: Mammalian milk microbiomes: sources of diversity, potential functions, and future research directions

Graphical abstract

Abstract

Milk is an ancient, fundamental mammalian adaptation that provides nutrition and biochemical communication to offspring. Microbiomes have been detected in milk of all species studied to date. In this review, we discuss: (a) routes by which microbes may enter milk; (b) evidence for proposed milk microbiome adaptive functions; (c) variation in milk microbiomes across mammals; and (d) future research directions, including suggestions for how to address outstanding questions on the viability and functionality of milk microbiomes. Milk microbes may be sourced from the maternal gastrointestinal tract, oral, skin, and mammary gland microbiomes and from neonatal oral and skin microbiomes. Given the variety of microbial sources, stochastic processes strongly influence milk microbiome assembly, but milk microbiomes appear to be influenced by maternal evolutionary history, diet, environment, and milk nutrients. Milk microbes have been proposed to colonize the neonatal intestinal tract and produce gene and metabolic products that influence physiology, metabolism, and immune system development. Limited epidemiological data indicate that early-life exposure to milk microbes can result in positive, long-term health outcomes. Milk microbiomes can be modified by dietary changes including providing the mother with probiotics and prebiotics. Milk replacers (i.e. infant formula) may benefit from supplementation with probiotics and prebiotics, but data are lacking on probiotics' usefulness, and supplementation should be evidence based. Overall, milk microbiome literature outside of human and model systems is scarce. We highlight the need for mechanistic studies in model species paired with comparative studies across mammals to further our understanding of mammalian milk microbiome evolution. A broader study of milk microbiomes has the potential to inform animal care with relevance to ex situ endangered species.

Lay summary

Milk is an ancient adaptation that supports the growth and development of mammalian neonates and infants. Beyond its fundamental nutritional function, milk influences all aspects of neonatal development, especially immune function. All kinds of milks so far studied have contained a milk microbiome. In this review, we focus on what is known about the collection of bacterial members found in milk microbiomes. Milk microbiomes include members sourced from maternal and infant microbiomes and they appear to be influenced by maternal evolutionary history, diet, milk nutrients, and environment, as well as by random chance. Once a neonate begins nursing, microbes from milk colonize their gut and produce byproducts that influence their physiology, metabolism, and immune development. Empirical data on milk microbiomes outside of humans and model systems are sparse. Greater study of milk microbiomes across mammals will expand our understanding of mammalian evolution and improve the health of animals under human care.

The Role of Diet and Nutritional Interventions for the Infant Gut Microbiome

The infant gut microbiome plays a key role in the healthy development of the human organism and appears to be influenced by dietary practices through multiple pathways. First, maternal diet during pregnancy and infant nutrition significantly influence the infant gut microbiota. Moreover, breastfeeding fosters the proliferation of beneficial bacteria, while formula feeding increases microbial diversity. The timing of introducing solid foods also influences gut microbiota composition. In preterm infants the gut microbiota development is influenced by multiple factors, including the time since birth and the intake of breast milk, and interventions such as probiotics and prebiotics supplementation show promising results in reducing morbidity and mortality in this population. These findings underscore the need for future research to understand the long-term health impacts of these interventions and for further strategies to enrich the gut microbiome of formula-fed and preterm infants.

From Birth to Weaning: A Window of Opportunity for Microbiota

(1) Background: The first 1000 days of life constitute a critical window of opportunity for microbiota development. Nutrients play a crucial role in enriching and diversifying the microbiota, derived not only from solid food but also from maternal dietary patterns during gestation. (2) Methods: We conducted a comprehensive literature review using the PubMed database, covering eleven years (2013-2023). We included English-language reviews, original research papers, and meta-analyses, while excluding case reports and letters. (3) Results: Consensus in the literature emphasizes that our interaction with a multitude of microorganisms begins in the intrauterine environment and continues throughout our lives. The existing data suggest that early nutritional education programs, initiated during pregnancy and guiding infant diets during development, may influence the shaping of the gut microbiota, promoting long-term health. (4) Conclusions: Further research is necessary in the coming years to assess potential interventions and early nutritional models aimed at modulating the pediatric microbiota, especially in vulnerable populations such as premature newborns.

The efficacy and safety of oral microecological agents as add-on therapy for atopic dermatitis: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Atopic dermatitis (AD) is a common skin disease that is hard to completely cure in a short time. Guidelines recommend the use of topical corticosteroids (TCS) as first-line anti-inflammatory therapy for AD, but long-term use has significant side effects. Microecological agents (MA), including probiotics, prebiotics and synbiotics, have been widely reported as a potential adjunctive therapy of AD, but whether MA can contribute to AD treatment is currently controversial. Therefore, we conducted a systematic review and meta-analysis to investigate whether MA as an add-on therapy for AD has synergistic and attenuated effects and to further understand the role of MA in clinical interventions for AD.

METHODS

We systematically searched Medline, Embase, Web of Science, Cochrane Library and PsycINFO databases up to Apr 11, 2023, and bibliographies were also manually searched, for potentially relevant studies regarding MA as additional therapy of AD. The Cochrane Risk of Bias Tool for assessing risk of bias was used to assess the quality of randomized controlled trials (RCTs). Two reviewers screened studies, extracted data, and evaluated the risk of bias independently. The primary outcomes (SCORAD scores and the number of adverse events) and the secondary outcomes (pruritus scores, the quality of life and the frequency of TCS) were extracted from each article. The data were combined and analyzed to quantify the safety and efficacy of the treatment. R (V4.4.3) software was used for data synthesis. The certainty of the evidence was evaluated with the Grade of Recommendation, Assessment, Development and Evaluation (GRADE) system. We also performed a trial sequential analysis to assess the reliability of the evidence.

RESULTS

A total of 21 studies, including 1230 individuals, were identified, 20 of which met the eligibility criteria for the meta-analysis. Our pooled meta-analyses showed that compared with controls, oral MA as an add-on therapy was associated with significantly lower SCORAD scores (MD = -5.30, 95% CI -8.50, -1.55, p < 0.01, I2  = 81%). However, adverse events, pruritus scores, quality of life, and frequency of TCS use showed no significant difference in this meta-analysis study (p > 0.05).

CONCLUSIONS

This meta-analysis showed that MA plus TCS could be an effective and safe treatment for patients with AD to relieve relevant symptoms, which might be used as an add-on therapy in the treatment of AD. However, due to the limited number of studies, results should be interpreted with caution. Further studies with a larger sample size are needed to explore the optimal protocol of MA plus TCS.

[Early life nutrition and immunity]

Introduction

The first 1,000 days of life, from conception to two years of age, are a critical time window for human growth and development, since the interaction of different factors can generate relevant changes in different structures and functions of the organism, both at short and long term. Most of the studies in this area have been carried out in the prenatal and neonatal period. Some of the most relevant factors that can affect immune development at this time are smoking, maternal obesity and inadequate intake of micronutrients during pregnancy. In the case of the postnatal period, breastfeeding is primarily the most important factor related to the nutritional and immunological status of the newborn, also being associated with a protective effect against obesity. Subsequently, the proper introduction of complementary feeding will be essential to offer an adequate percentage of nutrients. Likewise, the intestinal microbiota also plays a key role during this period since it is part of different metabolic, protective, and immunological functions of the host. Fluctuations in homeostasis will condition the appearance of dysbiosis, which is associated with the development of different diseases in childhood, adolescence, and adulthood.

Effects of Probiotic Saccharomyces boulardii Supernatant on Viability, Nano-Mechanical Properties of Cytoplasmic Membrane and Pro-Inflammatory Gene Expression in Human Gastric Cancer AGS Cells

BACKGROUND

Gastric cancer has been recognized as the second most probable cause of death in humans from cancer diseases around the world. Postbiotics, supernatant, and metabolites from probiotic microorganisms have recently been used widely to prevent and treat cancer diseases in humans, without any undesirable side effects. This study explores the antiproliferative and antitumor activities of the probiotic Saccharomyces cerevisiae var. boulardii supernatant (SBS) against AGS cancer cells, a human gastric adenocarcinoma cell line.

METHODS

We evaluated cell growth inhibitory and mechanical properties of the cytoplasmic membrane and the downregulation of survivin and proinflammatory genes in AGS cells treated with SBS after 24 and 48 h.

RESULTS

SBS significantly inhibits the AGS cell growth, and the concentrations with IC₅₀ values after 24 and 48 h treatments are measured as 2266 and 1956 µg/mL, respectively. Regarding the AFM images and Young`s modulus analysis, SBS significantly induces morphological changes in the cytoplasmic membrane of the treated AGS cells. Expression of survivin, NFƙB, and IL-8 genes is significantly suppressed in AGS cells treated with SBS.

CONCLUSIONS

Considering the antitumor activities of SBS on AGS cell line, it can be regarded as a prospective therapeutic and preventive strategy against human stomach cancer disease.