A mixture of prebiotic oligosaccharides reduces the incidence of atopic dermatitis during the first six months of age

Tailored recommendations for infant milk formula intake results in more accurate feeding

Currently available guidelines on the daily formula milk requirements of infants are based on the needs of infants with their growth pattern following the 50th percentile of the weight-for-age growth curve. Hence, current recommendations may not thoroughly detail the needs of infants across the broad spectrum of body weight percentiles. This study aimed to provide stratified recommendations for daily formula milk intake of fully formula-fed infants, across different weight-for-age categories from 0 to 4 months. At first, theoretical age- and gender-specific weight ranges were constructed for infants across five pre-defined weight-for-length percentile categories of the WHO growth standard. Thereafter, total daily energy requirements for each category were calculated and converted to daily formula milk needs. Subsequently, these stratified age- and weight-formula milk recommendations were compared to actual daily and relative formula milk of infants in these categories, retrieved from pooled individual infant formula milk intake data derived from 13 clinical intervention trials. A fitted regression model was used to evaluate differences in volume intakes across body weight categories as well as between theoretically derived and actual intake values. Median daily formula milk volume intake (ml/day) of infants differed significantly across the increasing weight-for-age categories at each time point, with significant differences between small and large infants. Interestingly, the relative daily formula milk volume intake (ml/kg/day) was higher for smaller infants compared to larger infants. The mean daily and relative formula milk intakes demonstrated the same pattern based on theoretical calculations as well as for the actual formula milk intake values retrieved from 13 pooled clinical intervention trials.

CONCLUSIONS

Based on theoretical calculations and actual formula intake data, we conclude that larger infants require a significantly higher daily formula milk intake than smaller infants, and we postulate that infants could benefit from more tailored formula milk intake recommendations.

WHAT IS KNOWN

• Adequate energy intake during the infancy period is crucial to support optimal growth and organ development, with the potential for long-lasting health effects. • Current available guidelines on the daily formula milk requirements of infants are based on the needs of infants with their growth pattern following the 50th percentile of the weight-for-age growth curve.

WHAT IS NEW

• Based on using both theoretical calculations and actual formula intake data, larger infants require a significantly higher daily formula milk intake than smaller infants. • Exclusive formula-fed infants could benefit from more tailored formula milk intake recommendations, in early infancy.

Perspective: Revisiting the Concepts of Prebiotic and Prebiotic Effect in Light of Scientific and Regulatory Progress - A Consensus Paper from the Global Prebiotic Association (GPA)

The term prebiotic has been used for almost three decades and has undergone numerous updates over the years. The scientific literature reveals that despite continuous efforts to establish a globally unified definition to guide jurisdictional regulations and product innovations, ambiguity continues to surround the terms prebiotic and prebiotic effect, leading to products that lack in full regulatory adherence being marketed worldwide. Thus, to reflect the current state of scientific research and knowledge and for the continuous advancement of the category, an update to the current prebiotic definition is warranted. This update includes removing the term selectivity, considering additional locations of action besides the gut, highlighting prebiotic performance benefits such as cognitive and athletic, and providing a clear standalone definition for prebiotic effect. The Global Prebiotic Association (GPA) is a leading information and industry hub committed to raising awareness about prebiotics, their emerging and well-established health benefits, and prebiotic product integrity and efficacy. In this position paper, GPA builds on previous prebiotic definitions to propose the following expanded definition for prebiotic: "a compound or ingredient that is utilized by the microbiota producing a health or performance benefit." In addition to prebiotic, GPA also defines prebiotic effect as: "a health or performance benefit that arises from alteration of the composition and/or activity of the microbiota, as a direct or indirect result of the utilization of a specific and well-defined compound or ingredient by microorganisms." With these two definitions, GPA aims to paint a clearer picture for the term prebiotic, and by incorporating an industry point of view, these updated definitions may be used alongside current scientific and regulatory perspectives to move the category forward. STATEMENT OF SIGNIFICANCE: The purpose of this paper is to revisit the concepts of prebiotic and prebiotic effect by providing a scientific-based industry perspective. The proposed definitions of prebiotic and prebiotic effect reflect the recent discoveries in metagenomics and prebiotic research after the International Scientific Association for Probiotics and Prebiotics' (ISAPP's) 2017 prebiotic definition and propose terminology changes that are timely and necessary. These changes aim to maintain the clarity and usefulness of the prebiotic definition to the scientific community, industry, healthcare providers, and consumers, while ensuring scientific validity, comprehensiveness, and justification of each part of the prebiotic definition, including abandoning the term selectivity and introducing concepts of performance benefits and prebiotic effect.

How maternal factors shape the immune system of breastfed infants to alleviate food allergy: A systematic and updated review

What infants eat early in life may shape the immune system and have long-standing consequences on the health of the host during later life. In the early months post-birth, breast milk serves as the exclusive and optimal nourishment for infants, facilitating crucial molecular exchanges between mother and infant. Recent advances have uncovered that some maternal factors influence breastfed infant outcomes, including the risk of food allergy (FA). To date, accumulated data show that breastfed infants have a lower risk of FA. However, the issue remains disputed, some reported preventive allergy effects, while others did not confirm such effects, or if identified, protective effects were limited to early childhood. The disputed outcomes may be attributed to the maternal status, as it determines the compounds of the breast milk that breastfed infants are exposed to. In this review, we first detail the compounds in breast milk and their roles in infant FA. Then, we present maternal factors resulting in alterations in breast milk compounds, such as maternal health status, maternal diet intake, and maternal food allergen intake, which subsequently impact FA in breastfed infants. Finally, we analyze how these compounds in breast milk alleviated the infant FA by mother-to-infant transmission. Altogether, the mechanisms are primarily linked to the synergetic and direct effects of compounds in breast milk, via promoting the colonization of gut microbiota and the development of the immune system in infants.

From Gut to Eye: Exploring the Role of Microbiome Imbalance in Ocular Diseases

Background: The gut microbiome plays a crucial role in human health, and recent research has highlighted its potential impact on ocular health through the gut-eye axis. Dysbiosis, or an imbalance in the gut microbiota, has been implicated in various ocular diseases. Methods: A comprehensive literature search was conducted using relevant keywords in major electronic databases, prioritizing recent peer-reviewed articles published in English. Results: The gut microbiota influences ocular health through immune modulation, maintenance of the blood-retinal barrier, and production of beneficial metabolites. Dysbiosis can disrupt these mechanisms, contributing to ocular inflammation, tissue damage, and disease progression in conditions such as uveitis, age-related macular degeneration, diabetic retinopathy, dry eye disease, and glaucoma. Therapeutic modulation of the gut microbiome through probiotics, prebiotics, synbiotics, and fecal microbiota transplantation shows promise in preclinical and preliminary human studies. Conclusions: The gut-eye axis represents a dynamic and complex interplay between the gut microbiome and ocular health. Targeting the gut microbiome through innovative therapeutic strategies holds potential for improving the prevention and management of various ocular diseases.

Effects of pregnancy and lactation prebiotics supplementation on infant allergic disease: A randomized controlled trial

BACKGROUND

Ingestion of prebiotics during pregnancy and lactation may have immunomodulatory benefits for the developing fetal and infant immune system and provide a potential dietary strategy to reduce the risk of allergic diseases.

OBJECTIVE

We sought to determine whether maternal supplementation with dietary prebiotics reduces the risk of allergic outcomes in infants with hereditary risk.

METHODS

We undertook a double-blind randomized controlled trial in which pregnant women were allocated to consume prebiotics (14.2 g daily of galacto-oligosaccharides and fructo-oligosaccharides in the ratio 9:1) or placebo (8.7 g daily of maltodextrin) powder from less than 21 weeks' gestation until 6 months postnatal during lactation. Eligible women had infants with a first-degree relative with a history of medically diagnosed allergic disease. The primary outcome was medically diagnosed infant eczema by age 1 year, and secondary outcomes included allergen sensitization, food allergy, and recurrent wheeze by age 1 year.

RESULTS

A total of 652 women were randomized between June 2016 and November 2021 (329 in the prebiotics group and 323 in the placebo group). There was no significant difference between groups in the percentage of infants with medically diagnosed eczema by age 1 year (prebiotics 31.5% [103 of 327 infants] vs placebo 32.6% [105 of 322 infants]; adjusted relative risk, 0.98; 95% CI, 0.77-1.23; P = .84). Secondary outcomes and safety measures also did not significantly differ between groups.

CONCLUSIONS

We found little evidence that maternal prebiotics supplementation during pregnancy and lactation reduces the risk of medically diagnosed infant eczema by age 1 year in infants who are at hereditary risk of allergic disease.

Exploring the skin microbiome in atopic dermatitis pathogenesis and disease modification

Inflammatory skin diseases such as atopic eczema (atopic dermatitis [AD]) affect children and adults globally. In AD, the skin barrier is impaired on multiple levels. Underlying factors include genetic, chemical, immunologic, and microbial components. Increased skin pH in AD is part of the altered microbial microenvironment that promotes overgrowth of the skin microbiome with Staphylococcus aureus. The secretion of virulence factors, such as toxins and proteases, by S aureus further aggravates the skin barrier deficiency and additionally disrupts the balance of an already skewed immune response. Skin commensal bacteria, however, can inhibit the growth and pathogenicity of S aureus through quorum sensing. Therefore, restoring a healthy skin microbiome could contribute to remission induction in AD. This review discusses direct and indirect approaches to targeting the skin microbiome through modulation of the skin pH; UV treatment; and use of prebiotics, probiotics, and postbiotics. Furthermore, exploratory techniques such as skin microbiome transplantation, ozone therapy, and phage therapy are discussed. Finally, we summarize the latest findings on disease and microbiome modification through targeted immunomodulatory systemic treatments and biologics. We believe that targeting the skin microbiome should be considered a crucial component of successful AD treatment in the future.

The role of glycans in health and disease: Regulators of the interaction between gut microbiota and host immune system

The human gut microbiota is home to a diverse collection of microorganisms that has co-evolved with the host immune system in which host-microbiota interactions are essential to preserve health and homeostasis. Evidence suggests that the perturbation of this symbiotic host-microbiome relationship contributes to the onset of major diseases such as chronic inflammatory diseases including Inflammatory Bowel Disease. The host glycocalyx (repertoire of glycans/sugar-chains at the surface of gut mucosa) constitutes a major biological and physical interface between the intestinal mucosa and microorganisms, as well as with the host immune system. Glycans are an essential niche for microbiota colonization and thus an important modulator of host-microorganism interactions both in homeostasis and in disease. In this review, we discuss the role of gut mucosa glycome as an instrumental pathway that regulates host-microbiome interactions in homeostasis but also in health to inflammation transition. We also discuss the power of mucosa glycosylation remodelling as an attractive preventive and therapeutic strategy to preserve gut homeostasis.

Dietary Galacto-oligosaccharides Ameliorate Atopic Dermatitis-like Skin Inflammation and Behavioral Deficits by Modulating Gut Microbiota-Brain-Skin Axis

Atopic dermatitis (AD), a chronic, highly pruritic, and inflammatory skin disorder, often coexists with psychiatric comorbidities including anxiety and depression, posing considerable challenges for treatment. The current research aims at evaluating the efficacy and potential therapeutic mechanism of galacto-oligosaccharides (GOS) on AD-like skin lesions and comorbid anxiety/depressive disorders. Macroscopical and histopathological examination showed that GOS could markedly relieve skin inflammation by decreasing the production of IgE, IL-4, IL-13, IFN-γ, and TNF-α and regulating the PPAR-γ/NF-κB signaling in DNFB-induced AD mice. Moreover, GOS significantly improved the anxiety- and depressive-like symptoms as mirrored by the behavior tests including FST, TST, OFT, and EZM through normalizing the neurotransmitter levels of 5-HT, DA, NE, and CORT in the brain. Mechanistically, by virtue of the high-throughput 16S rRNA gene sequencing and GC-MS techniques, GOS restructured the gut microbiota and specifically induced the proliferation of Lactobacillus and Alloprevotella, leading to an increase in the total content of fecal SCFAs, in particular acetate and butyrate. Pearson correlation analysis found a marked correlation among the altered gut microbiota/SCFAs, AD-associated skin manifestations, and comorbid behavioral phenotypes. Collectively, this work highlights that GOS is a promising strategy against both AD and associated depressive symptoms by modulating the gut microbiota-brain-skin axis.

2'-Fucosyllactose helps butyrate producers outgrow competitors in infant gut microbiota simulations

A reduced capacity for butyrate production by the early infant gut microbiota is associated with negative health effects, such as inflammation and the development of allergies. Here, we develop new hypotheses on the effect of the prebiotic galacto-oligosaccharides (GOS) or 2'-fucosyllactose (2'-FL) on butyrate production by the infant gut microbiota using a multiscale, spatiotemporal mathematical model of the infant gut. The model simulates a community of cross-feeding gut bacteria in metabolic detail. It represents the community as a grid of bacterial populations that exchange metabolites, using 20 different subspecies-specific metabolic networks taken from the AGORA database. The simulations predict that both GOS and 2'-FL promote the growth of Bifidobacterium, whereas butyrate producing bacteria are only consistently abundant in the presence of propane-1,2-diol, a product of 2'-FL metabolism. In absence of prebiotics or in presence of only GOS, however, Bacteroides vulgatus and Cutibacterium acnes outcompete butyrate producers by consuming intermediate metabolites.

Dietary Interventions in Atopic Dermatitis: A Comprehensive Scoping Review and Analysis

BACKGROUND

This scoping review aims to critically assess gaps in the current literature on atopic dermatitis (AD) by evaluating the overall effectiveness of dietary interventions. Through a comprehensive analysis that follows the Preferred Reporting Item for Systematic Review and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines, we conducted a thorough search on the Web of Science database in May 2023 using specific search strategies to identify all relevant studies on the research topic.

SUMMARY

A total of 104 full-text articles were included for review. Our synthesis identified seven notable categories of dietary interventions for AD, showcasing the diversity of interventions utilized. This includes vitamin supplementation, probiotic and prebiotic supplementation, dietary fat, biological compounds, foods from natural sources, major nutrients, and diet-related approaches. Further analyses stratified by targeted populations revealed a predominant focus on pediatrics, particularly in probiotic supplementation, and on adults, with an emphasis on vitamin D and E supplementation.

KEY MESSAGES

Despite most dietary interventions demonstrating overall effectiveness in improving AD severity and its subjective symptoms, several significant gaps were identified. There was a scarcity of studies on adults and whole-diet interventions, a prevalence of short-term interventions, heterogeneity in study outcomes, designs, and population, occasional disparity between statistical significance and clinical relevance, and a lack of a comprehensive multidisciplinary approach. Nonetheless, these findings offer valuable insights for future AD research, guiding additional evidence-driven dietary interventions and informing healthcare professionals, researchers, and individuals, advancing both understanding and management of AD.

Comparative prebiotic potential of galacto- and fructo-oligosaccharides, native inulin, and acacia gum in Kenyan infant gut microbiota during iron supplementation

Iron fortification to prevent anemia in African infants increases colonic iron levels, favoring the growth of enteropathogens. The use of prebiotics may be an effective strategy to reduce these detrimental effects. Using the African infant PolyFermS gut model, we compared the effect of the prebiotics short-chain galacto- with long-chain fructo-oligosaccharides (scGOS/lcFOS) and native inulin, and the emerging prebiotic acacia gum, a branched-polysaccharide-protein complex consisting of arabinose and galactose, during iron supplementation on four Kenyan infant gut microbiota. Iron supplementation did not alter the microbiota but promoted Clostridioides difficile in one microbiota. The prebiotic effect of scGOS/lcFOS and inulin was confirmed during iron supplementation in all investigated Kenyan infant gut microbiota, leading to higher abundance of bifidobacteria, increased production of acetate, propionate, and butyrate, and a significant shift in microbiota composition compared to non-supplemented microbiota. The abundance of the pathogens Clostridium difficile and Clostridium perfringens was also inhibited upon addition of the prebiotic fibers. Acacia gum had no effect on any of the microbiota. In conclusion, scGOS/lcFOS and inulin, but not acacia gum, showed a donor-independent strong prebiotic potential in Kenyan infant gut microbiota. This study demonstrates the relevance of comparing fibers in vitro prior to clinical studies.

The Interaction between the Host Genome, Epigenome, and the Gut-Skin Axis Microbiome in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that occurs in genetically predisposed individuals. It involves complex interactions among the host immune system, environmental factors (such as skin barrier dysfunction), and microbial dysbiosis. Genome-wide association studies (GWAS) have identified AD risk alleles; however, the associated environmental factors remain largely unknown. Recent evidence suggests that altered microbiota composition (dysbiosis) in the skin and gut may contribute to the pathogenesis of AD. Examples of environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, irritants, pollution, and microbial exposure. Studies have reported alterations in the gut microbiome structure in patients with AD compared to control subjects, characterized by increased abundance of Clostridium difficile and decreased abundance of short-chain fatty acid (SCFA)-producing bacteria such as Bifidobacterium. SCFAs play a critical role in maintaining host health, and reduced SCFA production may lead to intestinal inflammation in AD patients. The specific mechanisms through which dysbiotic bacteria and their metabolites interact with the host genome and epigenome to cause autoimmunity in AD are still unknown. By understanding the combination of environmental factors, such as gut microbiota, the genetic and epigenetic determinants that are associated with the development of autoantibodies may help unravel the pathophysiology of the disease. This review aims to elucidate the interactions between the immune system, susceptibility genes, epigenetic factors, and the gut microbiome in the development of AD.

Targeting the Gut-Eye Axis: An Emerging Strategy to Face Ocular Diseases

The human microbiota refers to a large variety of microorganisms (bacteria, viruses, and fungi) that live in different human body sites, including the gut, oral cavity, skin, and eyes. In particular, the presence of an ocular surface microbiota with a crucial role in maintaining ocular surface homeostasis by preventing colonization from pathogen species has been recently demonstrated. Moreover, recent studies underline a potential association between gut microbiota (GM) and ocular health. In this respect, some evidence supports the existence of a gut-eye axis involved in the pathogenesis of several ocular diseases, including age-related macular degeneration, uveitis, diabetic retinopathy, dry eye, and glaucoma. Therefore, understanding the link between the GM and these ocular disorders might be useful for the development of new therapeutic approaches, such as probiotics, prebiotics, symbiotics, or faecal microbiota transplantation through which the GM could be modulated, thus allowing better management of these diseases.

Fructo-oligofructose ameliorates 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions and psychiatric comorbidities in mice

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by pruritus and eczema lesions and psychiatric comorbidities. The gut-brain-skin axis plays a pivotal role during AD development, which might suggest a novel therapeutic strategy for AD. The present study aims to uncover the protective effects and underlying mechanisms of fructo-oligofructose (FOS), a type of prebiotic, on AD-like skin manifestations and comorbid anxiety and depression in AD mice.

RESULTS

Female Kunming mice were treated topically with 2,4-dinitrofluorobenzene (DNFB) to induce AD-like symptoms and FOS was administered daily for 14 days. The results showed that FOS could alleviate AD-like skin lesions markedly as evidenced by dramatic decreases in severity score, scratching bouts, the levels of immunoglobulin E (IgE) and T helper 1(Th1)/Th2-related cytokines, and the infiltration of inflammatory cells and mast cells to the dermal tissues. The comorbid anxiety and depressive-like behaviors, estimated by the forced swimming test (FST), the tail-suspension test (TST), the open-field test (OFT), and the zero maze test (ZMT) in AD mice, were significantly attenuated by FOS. Fructo-oligofructose significantly upregulated brain neurotransmitters levels of 5-hydroxytryptamine (5-HT) and dopamine (DA). Furthermore, FOS treatment increased the relative abundance of gut microbiota, such as Prevotella and Lactobacillus and the concentrations of short-chain fatty acids (SCFAs), especially acetate and iso-butyrate in the feces of AD mice. The correlation analysis indicated that the reshaped gut microbiome composition and enhanced SCFAs formation are associated with skin inflammation and behavioral alteration.

CONCLUSION

Collectively, these data identify FOS as a promising microbiota-targeted treatment for AD-like skin inflammation and comorbid anxiety and depressive-like behaviors. © 2023 Society of Chemical Industry.

Novel Dietary Approach with Probiotics, Prebiotics, and Synbiotics to Mitigate Antimicrobial Resistance and Subsequent Out Marketplace of Antimicrobial Agents: A Review

Antimicrobial resistance (AMR) is a significant public health concern worldwide. The continuous use and misuse of antimicrobial agents have led to the emergence and spread of resistant strains of bacteria, which can cause severe infections that are difficult to treat. One of the reasons for the constant development of new antimicrobial agents is the need to overcome the resistance that has developed against existing drugs. However, this approach is not sustainable in the long term, as bacteria can quickly develop resistance to new drugs as well. Additionally, the development of new drugs is costly and time-consuming, and there is no guarantee that new drugs will be effective or safe. An alternative approach to combat AMR is to focus on improving the body's natural defenses against infections by using probiotics, prebiotics, and synbiotics, which are helpful to restore and maintain a healthy balance of bacteria in the body. Probiotics are live microorganisms that can be consumed as food or supplements to promote gut health and improve the body's natural defenses against infections. Prebiotics are non-digestible fibers that stimulate the growth of beneficial bacteria in the gut, while synbiotics are a combination of probiotics and prebiotics that work together to improve gut health. By promoting a healthy balance of bacteria in the body, these can help to reduce the risk of infections and the need for antimicrobial agents. Additionally, these approaches are generally safe and well tolerated, and they do not contribute to the development of AMR. In conclusion, the continuous development of new antimicrobial agents is not a sustainable approach to combat AMR. Instead, alternative approaches such as probiotics, prebiotics, and synbiotics should be considered as they can help to promote a healthy balance of bacteria in the body and reduce the need for antibiotics.

Single-Strain Probiotic Lactobacilli for the Treatment of Atopic Dermatitis in Children: A Systematic Review and Meta-Analysis

Probiotics are known for their positive effects on the gut microbiota. There is growing evidence that the infant gut and skin colonization have a role in the development of the immune system, which may be helpful in the prevention and treatment of atopic dermatitis. This systematic review focused on evaluating the effect of single-strain probiotic lactobacilli consumption on treating children's atopic dermatitis. Seventeen randomized placebo-controlled trials with the primary outcome of the Scoring Atopic Dermatitis (SCORAD) index were included in the systematic review. Clinical trials using single-strain lactobacilli were included. The search was conducted until October 2022 using PubMed, ScienceDirect, Web of Science, Cochrane library and manual searches. The Joanna Briggs Institute appraisal tool was used to assess the quality of the included studies. Meta-analyses and sub meta-analyses were performed using Cochrane Collaboration methodology. Due to different methods of reporting the SCORAD index, only 14 clinical trials with 1124 children were included in the meta-analysis (574 in the single-strain probiotic lactobacilli group and 550 in the placebo group) and showed that single-strain probiotic lactobacilli statistically significantly reduced the SCORAD index compared to the placebo in children with atopic dermatitis (mean difference [MD]: -4.50; 95% confidence interval [CI]: -7.50 to -1.49; Z = 2.93; p = 0.003; heterogeneity I² = 90%). The subgroup meta-analysis showed that strains of Limosilactobacillus fermentum were significantly more effective than strains of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei or Lacticaseibacillus rhamnosus. A longer treatment time and younger treatment age statistically significantly reduced symptoms of atopic dermatitis. The result of this systematic review and meta-analysis shows that certain single-strain probiotic lactobacilli are more successful than others in reducing atopic dermatitis severity in children. Therefore, careful consideration to strain selection, treatment time and the age of the treated patients are important factors in enhancing the effectiveness of reducing atopic dermatitis in children when choosing probiotic single-strain lactobacilli.

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

The first objective of infant formulas is to ensure the healthy growth of neonates and infants, as the sole complete food source during the first months of life when a child cannot be breastfed. Beyond this nutritional aspect, infant nutrition companies also try to mimic breast milk in its unique immuno-modulating properties. Numerous studies have demonstrated that the intestinal microbiota under the influence of diet shapes the maturation of the immune system and influences the risk of atopic diseases in infants. A new challenge for dairy industries is, therefore, to develop infant formulas inducing the maturation of immunity and the microbiota that can be observed in breastfed delivered vaginally, representing reference infants. Streptococcus thermophilus, Lactobacillus reuteri DSM 17938, Bifidobacterium breve (BC50), Bifidobacterium lactis Bb12, Lactobacillus fermentum (CECT5716), and Lactobacillus rhamnosus GG (LGG) are some of the probiotics added to infant formula, according to a literature review of the past 10 years. The most frequently used prebiotics in published clinical trials are fructo-oligosaccharides (FOSs), galacto-oligosaccharides (GOSs), and human milk oligosaccharides (HMOs). This review sums up the expected benefits and effects for infants of pre-, pro-, syn-, and postbiotics added to infant formula regarding the microbiota, immunity, and allergies.

Microbiome and Human Health: Current Understanding, Engineering, and Enabling Technologies

The human microbiome is composed of a collection of dynamic microbial communities that inhabit various anatomical locations in the body. Accordingly, the coevolution of the microbiome with the host has resulted in these communities playing a profound role in promoting human health. Consequently, perturbations in the human microbiome can cause or exacerbate several diseases. In this Review, we present our current understanding of the relationship between human health and disease development, focusing on the microbiomes found across the digestive, respiratory, urinary, and reproductive systems as well as the skin. We further discuss various strategies by which the composition and function of the human microbiome can be modulated to exert a therapeutic effect on the host. Finally, we examine technologies such as multiomics approaches and cellular reprogramming of microbes that can enable significant advancements in microbiome research and engineering.

Gastrointestinal Effects and Tolerance of Nondigestible Carbohydrate Consumption

Nondigestible carbohydrates (NDCs) are food components, including nonstarch polysaccharides and resistant starches. Many NDCs are classified as dietary fibers by the US FDA. Because of their beneficial effects on human health and product development, NDCs are widely used in the food supply. Although there are dietary intake recommendations for total dietary fiber, there are no such recommendations for individual NDCs. NDCs are heterogeneous in their chemical composition and physicochemical properties-characteristics that contribute to their tolerable intake levels. Guidance on tolerable intake levels of different NDCs is needed because overconsumption can lead to undesirable gastrointestinal side effects, further widening the gap between actual and suggested fiber intake levels. In this review, we synthesize the literature on gastrointestinal effects of NDCs that the FDA accepts as dietary fibers (β-glucan, pectin, arabinoxylan, guar gum, alginate, psyllium husk, inulin, fructooligosaccharides and oligofructose, galactooligosaccharides, polydextrose, cellulose, soy fiber, resistant maltodextrin/dextrin) and present tolerable intake dose recommendations for their consumption. We summarized the findings from 103 clinical trials in adults without gastrointestinal disease who reported gastrointestinal effects, including tolerance (e.g., bloating, flatulence, borborygmi/rumbling) and function (e.g., transit time, stool frequency, stool consistency). These studies provided doses ranging from 0.75-160 g/d and lasted for durations ranging from a single-meal tolerance test to 28 wk. Tolerance was NDC specific; thus, recommendations ranged from 3.75 g/d for alginate to 25 g/d for soy fiber. Future studies should address gaps in the literature by testing a wider range of NDC doses and consumption forms (solid compared with liquid). Furthermore, future investigations should also adopt a standard protocol to examine tolerance and functional outcomes across studies consistently.

Biological activity of galacto-oligosaccharides: A review

Galacto-oligosaccharides (GOS) are oligosaccharides formed by β-galactosidase transgalactosylation. GOS is an indigestible food component that can pass through the upper gastrointestinal tract relatively intact and ferment in the colon to produce short-chain fatty acids (SCFAs) that further regulate the body’s intestinal flora. GOS and other prebiotics are increasingly recognized as useful food tools for regulating the balance of colonic microbiota-human health. GOS performed well compared to other oligosaccharides in regulating gut microbiota, body immunity, and food function. This review summarizes the sources, classification, preparation methods, and biological activities of GOS, focusing on the introduction and summary of the effects of GOS on ulcerative colitis (UC), to gain a comprehensive understanding of the application of GOS.

Study Protocol for a Randomised Controlled Trial Investigating the Effects of Maternal Prebiotic Fibre Dietary Supplementation from Mid-Pregnancy to Six Months’ Post-Partum on Child Allergic Disease Outcomes

Infant allergy is the most common early manifestation of an increasing propensity for inflammation and immune dysregulation in modern environments. Refined low-fibre diets are a major risk for inflammatory diseases through adverse effects on the composition and function of gut microbiota. This has focused attention on the potential of prebiotic dietary fibres to favourably change gut microbiota, for local and systemic anti-inflammatory effects. In pregnancy, the immunomodulatory effects of prebiotics may also have benefits for the developing fetal immune system, and provide a potential dietary strategy to reduce the risk of allergic disease. Here, we present the study protocol for a double-blinded, randomised controlled trial investigating the effects of maternal prebiotics supplementation on child allergic disease outcomes. Eligible pregnant women have infants with a first-degree relative with a history of medically diagnosed allergic disease. Consented women are randomised to consume either prebiotics (galacto-oligosaccharides and fructo-oligosaccharides) or placebo (maltodextrin) powder daily from 18–20 weeks’ gestation to six months’ post-partum. The target sample size is 652 women. The primary outcome is infant medically diagnosed eczema; secondary outcomes include allergen sensitisation, food allergies and recurrent wheeze. Breast milk, stool and blood samples are collected at multiple timepoints for further analysis.

D-galactose Intake Alleviates Atopic Dermatitis in Mice by Modulating Intestinal Microbiota

Atopic dermatitis (AD) is one of the most prevalent, chronic and persistent inflammatory skin diseases closely associated with intestinal microbiota. To evaluate the effect of D-galactose intake on AD, we orally administered D-galactose to BALB/c mice whose ears and skin were treated with 2,4-dinitrochlorobenzene (DNCB). D-galactose alleviated DNCB-induced AD-like phenotypes such as redness, scaling/dryness and excoriation. Ear thickness was also decreased by D-galactose administration. Histopathological analysis revealed decreased epidermal thickening, infiltration of immune cells, especially mast cells, in the dermis. Total levels of serum IgE representing the immunological response of AD were decreased by D-galactose administration. Microbiota analysis showed that D-galactose administration restored gut microbiota profiles, which were altered in AD mice, characterized by increased abundance of Bacteroidetes and decreased abundance of Firmicutes. The increased abundance of Bacteroides and the decreased abundance of Prevotella and Ruminococcus were reversed by D-galactose treatment, following improvement of AD. Our results suggest the possible use of D-galactose as a prebiotic to alleviate AD by altering gut microbiota.

Ameliorating the efficacy of galacto-oligosaccharides on ovalumin-induced allergic dermatitis symptoms in Balb/c mice by regulating Th2 immune response and the ecosystem of gut microbiota

In this study, we evaluated the effect of oral administration of galacto-oligosaccharide (GOS), famous biological molecules that are comprised of galactose and lactose, on ovalbumin (OVA)-induced allergic dermatitis. OVA-induced mice were divided into the OVA-administered group (OVA-C), promethazine hydrochloride-administered group (PC), and 100 and 200 mg kg^-1 GOS-administered groups (GL and GH, respectively). GOS administration significantly improved epidermal thickness and decreased CD4⁺ cell numbers. The concentrations of IgE, OVA-specific IgE, and inflammatory cytokines (IL-4, IL-5, and INF-γ) in GH group mice were significantly lower than those in OVA-C group mice. Firmicutes and Bacteroidetes were identified as the major phyla in the intestinal microbiota in mice, and the relative abundance of Deferribacteres was significantly lower in the GH group than in the OVA-C group. Deferribacteraceae and Mucispirillum species were significantly lower in the GH group than in the OVA-C group. The relative abundance of Muribaculum species was significantly lower, but those of Lachnospira and Lactococcus species were significantly higher in the GH group than in the OVA-C group. Our results suggest that the alleviation effect of GOS on allergic dermatitis induced by OVA sensitization was achieved by regulating hypersensitive immune responses by improving the intestinal microbial ecosystem.

Manipulating Microbiota to Treat Atopic Dermatitis: Functions and Therapies

Atopic dermatitis (AD) is a globally prevalent skin inflammation with a particular impact on children. Current therapies for AD are challenged by the limited armamentarium and the high heterogeneity of the disease. A novel promising therapeutic target for AD is the microbiota. Numerous studies have highlighted the involvement of the skin and gut microbiota in the pathogenesis of AD. The resident microbiota at these two epithelial tissues can modulate skin barrier functions and host immune responses, thus regulating AD progression. For example, the pathogenic roles of Staphylococcus aureus in the skin are well-established, making this bacterium an attractive target for AD treatment. Targeting the gut microbiota is another therapeutic strategy for AD. Multiple oral supplements with prebiotics, probiotics, postbiotics, and synbiotics have demonstrated promising efficacy in both AD prevention and treatment. In this review, we summarize the association of microbiota dysbiosis in both the skin and gut with AD, and the current knowledge of the functions of commensal microbiota in AD pathogenesis. Furthermore, we discuss the existing therapies in manipulating both the skin and gut commensal microbiota to prevent or treat AD. We also propose potential novel therapies based on the cutting-edge progress in this area.

Synbiotic containing extensively hydrolyzed formula improves gastrointestinal and atopic symptom severity, growth, caregiver quality of life, and hospital-related healthcare use in infants with cow's milk allergy

Background

Healthy gut microbiota is important for prognosis in cow's milk allergy (CMA). The application of synbiotics (specific pre‐ and probiotics) in extensively hydrolyzed formulae (eHFs) is a relatively new concept.

Aims

To evaluate a synbiotic‐containing, whey‐based eHF (SeHF) with galacto‐oligosaccharides, fructo‐oligosaccharides, and bifidobacterium breve M‐16V in infants with CMA.

Materials and Methods

A 31‐day one‐arm pilot study in 29 infants with CMA (mean age 30.8 weeks [SD 11]) was undertaken, with outcomes including gastrointestinal tolerance, atopic dermatitis symptoms, dietary intake, growth, SeHF acceptability, caregiver quality of life, and hospital‐related healthcare use.

Results

Significant improvements (p < .05) in the severity of abdominal pain (in 57%), burping (in 46%), flatulence (in 79%), constipation (in 14%), rhinitis (41%), and itchy eyes (73%), as well as atopic dermatitis in those with severe baseline symptoms (PO‐SCORAD^© reduction: 34.7–18.2 (p = .003), n = 6) were observed over time. Growth and caregiver quality of life scores significantly increased (+26.7%, p < .05) over time. Hospital visits and medications significantly reduced (−1.61 and −2.23, respectively, p < .005) in the 6 months after SeHF initiation.

Discussion

In this small, single‐arm, pilot study, the use of SeHF enhanced the management of infants with non‐IgE mediated CMA who were already established on eHF. Conclusion: Whilst this study adds to the evidence base for the use of SeHF in CMA, further robust research to explore the longer‐term benefits of synbiotics, specifically the blend used in this study, for the clinical management of infants with CMA is warranted.

Probiotics, prebiotics, and synbiotics to prevent or combat air pollution consequences: The gut-lung axis

Air pollution exposure is a public health emergency, which attributes globally to an estimated seven million deaths on a yearly basis We are all exposed to air pollutants, varying from ambient air pollution hanging over cities to dust inside the home. It is a mixture of airborne particulate matter and gases that can be subdivided into three categories based on particle diameter. The smallest category called PM_0.1 is the most abundant. A fraction of the particles included in this category might enter the blood stream spreading to other parts of the body. As air pollutants can enter the body via the lungs and gut, growing evidence links its exposure to gastrointestinal and respiratory impairments and diseases, like asthma, rhinitis, respiratory tract infections, Crohn's disease, ulcerative colitis, and abdominal pain. It has become evident that there exists a crosstalk between the respiratory and gastrointestinal tracts, commonly referred to as the gut-lung axis. Via microbial secretions, metabolites, immune mediators and lipid profiles, these two separate organ systems can influence each other. Well-known immunomodulators and gut health stimulators are probiotics, prebiotics, together called synbiotics. They might combat air pollution-induced systemic inflammation and oxidative stress by optimizing the microbiota composition and microbial metabolites, thereby stimulating anti-inflammatory pathways and strengthening mucosal and epithelial barriers. Although clinical studies investigating the role of probiotics, prebiotics, and synbiotics in an air pollution setting are lacking, these interventions show promising health promoting effects by affecting the gastrointestinal- and respiratory tract. This review summarizes the current data on how air pollution can affect the gut-lung axis and might impact gut and lung health. It will further elaborate on the potential role of probiotics, prebiotics and synbiotics on the gut-lung axis, and gut and lung health.

Early-life fecal microbiome and metabolome dynamics in response to an intervention with infant formula containing specific prebiotics and postbiotics

This study examined fecal metabolome dynamics to gain greater functional insights into the interactions between nutrition and the activity of the developing gut microbiota in healthy term-born infants. The fecal samples used here originate from a randomized, controlled, double-blind clinical study that assessed the efficacy of infant formula with prebiotics and postbiotics (experimental arm) compared with a standard infant formula (control arm). A group of exclusively breast-fed term infants was used as a reference arm. First, conventional targeted physiological and microbial measurements were performed, which showed differences in fecal Bifidobacterium levels and corresponding activity (e.g., lactate levels). Next, the overall fecal microbiota composition was determined by 16S rRNA gene amplicon sequencing. The microbiota composition profiles showed several bacterial groups in the experimental arm to be significantly different from the control arm and mostly closer to the levels observed in the reference arm. Finally, we applied an untargeted UPLC-MS/MS approach to examine changes in the fecal metabolome. Fecal metabolome profiles showed the most distinct separation, up to 404 significantly different metabolites, between the study arms. Our data reveal that infant formula with specific prebiotics and postbiotics may trigger responses in the intestinal microbiota composition that brings the ensuing fecal metabolite profile of formula-fed infants closer toward those observed in breast-fed infants. Furthermore, our results demonstrate a clear need for establishing an infant gut metabolome reference database to translate these metabolite profile dynamics into functional and physiologically relevant responses.NEW & NOTEWORTHY Untargeted metabolomics techniques can provide a "snapshot" of an ecosystem in response to environmental stimuli, such as nutritional interventions. Our analyses of fecal samples from infants demonstrate the potential of phenotyping by metabolomics while deciphering the complex interactions of early-life nutrition and gut microbiome development.

Intestinal Barrier Permeability in Allergic Diseases

The role of intestinal permeability (IP) markers among children and adults with food allergies is not fully understood, and the identification of biological indicators/markers that predict growth retardation in children with allergic diseases and atopy has not been well explained. Studies have shown that patients with atopic diseases respond abnormally to food allergens. Accordingly, differences in the types of immune complexes formed in response to antigen challenges are significant, which seems to underlie the systemic signs of the food allergy. Increased intestinal permeability over the course of a food allergy allows allergens to penetrate through the intestinal barrier and stimulate the submucosal immune system. Additionally, the release of cytokines and inflammatory mediators enhances the degradation of the epithelial barrier and leads to an improper cycle, resulting in increased intestinal permeability. Several studies have also demonstrated increased permeability of the epithelial cells in those afflicted with atopic eczema and bronchial asthma. Ongoing research is aimed at finding various indicators to assess IP in patients with atopic diseases.

Modulation of the Epithelial-Immune Cell Crosstalk and Related Galectin Secretion by DP3-5 Galacto-Oligosaccharides and β-3′Galactosyllactose

Prebiotic galacto-oligosaccharides (GOS) were shown to support mucosal immune development by enhancing regulatory-type Th1 immune polarization induced by synthetic CpG oligodeoxynucleotides (TLR9 agonist mimicking a bacterial DNA trigger). Epithelial-derived galectin-9 was associated with these immunomodulatory effects. We aimed to identify the most active fractions within GOS based on the degree of polymerization (DP), and to study the immunomodulatory capacities of DP3-sized β-3′galactosyllactose (β-3′GL) using a transwell co-culture model of human intestinal epithelial cells (IEC) and activated peripheral blood mononuclear cells (PBMC). IEC were apically exposed to different DP fractions of GOS or β-3′GL in the presence of CpG, and basolaterally co-cultured with αCD3/CD28-activated PBMC, washed, and incubated in fresh medium for IEC-derived galectin analysis. Only DP3-5 in the presence of CpG enhanced galectin-9 secretion. DP3-sized β-3′GL promoted a regulatory-type Th1 response by increasing IFNγ and IL-10 or galectin-9 concentrations as compared to CpG alone. In addition, IEC-derived galectin-3, -4, and -9 secretion was increased by β-3′GL when combined with CpG. Therefore, the GOS DP3-5 and most effectively DP3-sized β-3′GL supported the immunomodulatory properties induced by CpG by enhancing epithelial-derived galectin secretion, which, in turn, could support mucosal immunity.

Analysing the protection from respiratory tract infections and allergic diseases early in life by human milk components: the PRIMA birth cohort

Background

Many studies support the protective effect of breastfeeding on respiratory tract infections. Although infant formulas have been developed to provide adequate nutritional solutions, many components in human milk contributing to the protection of newborns and aiding immune development still need to be identified. In this paper we present the methodology of the “Protecting against Respiratory tract lnfections through human Milk Analysis” (PRIMA) cohort, which is an observational, prospective and multi-centre birth cohort aiming to identify novel functions of components in human milk that are protective against respiratory tract infections and allergic diseases early in life.

Methods

For the PRIMA human milk cohort we aim to recruit 1000 mother–child pairs in the first month postpartum. At one week, one, three, and six months after birth, fresh human milk samples will be collected and processed. In order to identify protective components, the level of pathogen specific antibodies, T cell composition, Human milk oligosaccharides, as well as extracellular vesicles (EVs) will be analysed, in the milk samples in relation to clinical data which are collected using two-weekly parental questionnaires. The primary outcome of this study is the number of parent-reported medically attended respiratory infections. Secondary outcomes that will be measured are physician diagnosed (respiratory) infections and allergies during the first year of life.

Discussion

The PRIMA human milk cohort will be a large prospective healthy birth cohort in which we will use an integrated, multidisciplinary approach to identify the longitudinal effect human milk components that play a role in preventing (respiratory) infections and allergies during the first year of life. Ultimately, we believe that this study will provide novel insights into immunomodulatory components in human milk. This may allow for optimizing formula feeding for all non-breastfed infants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07107-w.

An Infant Formula with Large, Milk Phospholipid-Coated Lipid Droplets Supports Adequate Growth and Is Well-Tolerated in Healthy, Term Asian Infants: A Randomized, Controlled Double-Blind Clinical Trial

Lipids are essential for healthy infant growth and development. The structural complexity of lipids in human milk is not present in infant milk formula (IF). A concept IF was developed mimicking more closely the structure and composition of human milk fat globules. The current study evaluates whether a concept IF with large, milk phospholipid-coated lipid droplets (mode diameter 3 to 5 μm) is equivalent to standard IF with regard to growth adequacy and safety in healthy, term Asian infants. In this randomized, double-blind, controlled trial, infants were randomized after parents decided to introduce formula. Infants received a standard IF with (Control) or without the specific prebiotic mixture scGOS/lcFOS (9:1 ratio; Control w/o prebiotics), or a Concept IF with large, milk phospholipid-coated lipid droplets and the prebiotic mixture. A group of 67 breastfed infants served as a reference. As a priori defined, only those infants who were fully intervention formula-fed ≤28 days of age were included in the equivalence analysis (Control n = 29; Control w/o prebiotics n = 28; Concept n = 35, per-protocol population). Primary outcome was daily weight gain during the first four months of life, with the difference between the Concept and Control as the key comparison of interest. Additionally, adverse events, growth and tolerance parameters were evaluated. Equivalence of daily weight gain was demonstrated between the Concept and Control group after additional correction for ethnicity and birthweight (difference in estimated means of 0.1 g/d, 90%CI [-2.30, 2.47]; equivalence margin +/- 3 g/d). No clinically relevant group differences were observed in secondary growth outcomes, tolerance outcomes or number, severity or relatedness of adverse events. This study corroborates that an infant formula with large, milk phospholipid-coated lipid droplets supports adequate growth and is well tolerated and safe for use in healthy infants.

What Do We Know about the Microbiome in Cystic Fibrosis? Is There a Role for Probiotics and Prebiotics?

Cystic fibrosis (CF) is a life-shortening genetic disorder that affects the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In the gastrointestinal (GI) tract, CFTR dysfunction results in low intestinal pH, thick and inspissated mucus, a lack of endogenous pancreatic enzymes, and reduced motility. These mechanisms, combined with antibiotic therapies, drive GI inflammation and significant alteration of the GI microbiota (dysbiosis). Dysbiosis and inflammation are key factors in systemic inflammation and GI complications including malignancy. The following review examines the potential for probiotic and prebiotic therapies to provide clinical benefits through modulation of the microbiome. Evidence from randomised control trials suggest probiotics are likely to improve GI inflammation and reduce the incidence of CF pulmonary exacerbations. However, the highly variable, low-quality data is a barrier to the implementation of probiotics into routine CF care. Epidemiological studies and clinical trials support the potential of dietary fibre and prebiotic supplements to beneficially modulate the microbiome in gastrointestinal conditions. To date, limited evidence is available on their safety and efficacy in CF. Variable responses to probiotics and prebiotics highlight the need for personalised approaches that consider an individual’s underlying microbiota, diet, and existing medications against the backdrop of the complex nutritional needs in CF.

Consumer's acceptability and health consciousness of probiotic and prebiotic of non-dairy products

Human gut microbiota is a protective agent of intestinal and systemic health, and its modulation is of great interest for human wellbeing. In the world of biotics, besides probiotics, prebiotics, and synbiotics, also appears the denomination of "postbiotics" and "psychobiotics". Fermented dairy products are, traditionally, the major source of probiotics. Nevertheless, due to the increasing number of lactose-intolerant individuals and strict vegetarians, there is a need for innovative non-dairy products. Non-dairy biotics are being included in the normal diet and due to technological advances, many products are created using non-conventional food matrices like kombucha tea, herbal tea, baking mix, and cereal-based products. The microorganisms most used as probiotics in many of the non-dairy products are strains belonging to the genera Bifidobacterium, Enterococcus, Lactobacillus, Lactococcus, Streptococcus, and Bacillus, and some yeast strains namely Saccharomyces cerevisiae var. boulardii. Recently, several other yeasts have been described as having probiotic properties. This review describes gut-derived effects in humans of possible microorganisms, such as yeasts, and bacteria, isolated from non-dairy fermented and non-fermented foods and beverages. The microorganisms responsible for the processing of these non-dairy fermented products, together with the prebiotics, form a class of nutrients that have been proven to be beneficial for our gut health.

Dietary Supplementation throughout Life with Non-Digestible Oligosaccharides and/or n-3 Poly-Unsaturated Fatty Acids in Healthy Mice Modulates the Gut-Immune System-Brain Axis

The composition and activity of the intestinal microbial community structures can be beneficially modulated by nutritional components such as non-digestible oligosaccharides and omega-3 poly-unsaturated fatty acids (n-3 PUFAs). These components affect immune function, brain development and behaviour. We investigated the additive effect of a dietary combination of scGOS:lcFOS and n-3 PUFAs on caecal content microbial community structures and development of the immune system, brain and behaviour from day of birth to early adulthood in healthy mice. Male BALB/cByJ mice received a control or enriched diet with a combination of scGOS:lcFOS (9:1) and 6% tuna oil (n-3 PUFAs) or individually scGOS:lcFOS (9:1) or 6% tuna oil (n-3 PUFAs). Behaviour, caecal content microbiota composition, short-chain fatty acid levels, brain monoamine levels, enterochromaffin cells and immune parameters in the mesenteric lymph nodes (MLN) and spleen were assessed. Caecal content microbial community structures displayed differences between the control and dietary groups, and between the dietary groups. Compared to control diet, the scGOS:lcFOS and combination diets increased caecal saccharolytic fermentation activity. The diets enhanced the number of enterochromaffin cells. The combination diet had no effects on the immune cells. Although the dietary effect on behaviour was limited, serotonin and serotonin metabolite levels in the amygdala were increased in the combination diet group. The combination and individual interventions affected caecal content microbial profiles, but had limited effects on behaviour and the immune system. No apparent additive effect was observed when scGOS:lcFOS and n-3 PUFAs were combined. The results suggest that scGOS:lcFOS and n-3 PUFAs together create a balance-the best of both in a healthy host.

Dietary Fibers: Effects, Underlying Mechanisms and Possible Role in Allergic Asthma Management

The prevalence of asthma is increasing, but the cause remains under debate. Research currently focuses on environmental and dietary factors that may impact the gut-lung axis. Dietary fibers are considered to play a crucial role in supporting diversity and activity of the microbiome, as well as immune homeostasis in the gut and lung. This review discusses the current state of knowledge on how dietary fibers and their bacterial fermentation products may affect the pathophysiology of allergic asthma. Moreover, the impact of dietary fibers on early type 2 asthma management, as shown in both pre-clinical and clinical studies, is described. Short-chain fatty acids, fiber metabolites, modulate host immunity and might reduce the risk of allergic asthma development. Underlying mechanisms include G protein-coupled receptor activation and histone deacetylase inhibition. These results are supported by studies in mice, children and adults with allergic asthma. Fibers might also exert direct effects on the immune system via yet to be elucidated mechanisms. However, the effects of specific types of fiber, dosages, duration of treatment, and combination with probiotics, need to be explored. There is an urgent need to further valorize the potential of specific dietary fibers in prevention and treatment of allergic asthma by conducting more large-scale dietary intervention trials.

Atopic dermatitis and nutrition

Atopic dermatitis, a common chronic and pruritic inflammatory skin disorder, can create significant disruptions in sleep and quality of life. Atopic dermatitis is especially common in infants and children; therefore, safe and natural therapeutic options have considerable appeal. Over the past several decades, there has been an increase in the prevalence of atopic dermatitis in industrialized nations. Also, there is variability in the prevalence of atopic dermatitis in the United States, both across and within states. Environmental factors including diet are believed to be associated with this increased risk. Dietary interventions continue to be an area of keen interest and have been studied extensively, albeit with variable results. Maternal dietary restrictions during pregnancy and lactation, hydrolyzed or partially hydrolyzed formulas, delaying the introduction of solid foods, and omega-3 or omega-6 fatty acids supplementation do not appear to have a beneficial effect on the treatment and prevention of atopic dermatitis. Exclusive breastfeeding for 3 to 4 months, a diet high in fruits and vegetables, and prebiotics might have a beneficial effect. Because environmental triggers, including dietary exposures, are thought to play a role in the pathogenesis of atopic dermatitis, we herein review the current literature on the role of dietary habits, vitamin and mineral supplementation, and probiotics on the treatment and prevention of atopic dermatitis.

Microbiome Modulation as a Therapeutic Approach in Chronic Skin Diseases

There is a growing quantity of evidence on how skin and gut microbiome composition impacts the course of various dermatological diseases. The strategies involving the modulation of bacterial composition are increasingly in the focus of research attention. The aim of the present review was to analyze the literature available in PubMed (MEDLINE) and EMBASE databases on the topic of microbiome modulation in skin diseases. The effects and possible mechanisms of action of probiotics, prebiotics and synbiotics in dermatological conditions including atopic dermatitis (AD), psoriasis, chronic ulcers, seborrheic dermatitis, burns and acne were analyzed. Due to the very limited number of studies available regarding the topic of microbiome modulation in all skin diseases except for AD, the authors decided to also include case reports and original studies concerning oral administration and topical application of the pro-, pre- and synbiotics in the final analysis. The evaluated studies mostly reported significant health benefits to the patients or show promising results in animal or ex vivo studies. However, due to a limited amount of research and unambiguous results, the topic of microbiome modulation as a therapeutic approach in skin diseases still warrants further investigation.

Potential Biomarkers, Risk Factors and their Associations with IgE-mediated Food Allergy in Early Life: A Narrative Review

Food allergy affects the quality of life of millions of people worldwide and presents a significant psychological and financial burden for both national and international public health. In the past few decades, the prevalence of allergic disease has been on the rise worldwide. Identified risk factors for food allergy include family history, mode of delivery, variations in infant feeding practices, prior diagnosis of other atopic diseases such as eczema, and social economic status. Identifying reliable biomarkers which predict the risk of developing food allergy in early life would be valuable in both preventing morbidity and mortality and by making current interventions available at the earliest opportunity. There is also the potential to identify new therapeutic targets. This narrative review provides details on the genetic, epigenetic, dietary and microbiome influences upon the development of food allergy and synthesizes the currently available data indicating potential biomarkers. While there is a large body of research evidence available within each field of potential risk factors, there are very limited number of studies which span multiple methodological fields, for example including immunology, microbiome, genetic/epigenetic factors and dietary assessment. We recommend that further collaborative research with detailed cohort phenotyping is required to identify biomarkers, and whether these vary between at-risk populations and the wider population. The low incidence of oral food challenge confirmed food allergy in the general population, and the complexities of designing nutritional intervention studies will provide challenges for researchers to address in generating high quality, reliable and reproducible research findings.

STATEMENT OF SIGNIFICANCE

Food allergy affects the quality of life of millions of people worldwide and presents a significant psychological and financial burden for both national and international public health. Identifying reliable biomarkers which predict the risk of developing food allergy would be valuable in both preventing morbidity and mortality and by making current interventions available at the earliest opportunity. This review provides details on the genetic, epigenetic, dietary and microbiome influences upon the development of food allergy. This helps in identifying reliable biomarkers to predict the risk of developing food allergy, which could be valuable in both preventing morbidity and mortality and by making interventions available at the earliest opportunity.

Galacto-oligosaccharides as infant prebiotics: production, application, bioactive activities and future perspectives

Galacto-oligosaccharides (GOS) are non-digestible oligosaccharides characterized by a mix of structures that vary in their degree of polymerization (DP) and glycosidic linkage between the galactose moieties or between galactose and glucose. They have enjoyed extensive scientific scrutiny, and their health-promoting effects are supported by a large number of scientific and clinical studies. A variety of GOS-associated health-promoting effects have been reported, such as growth promotion of beneficial bacteria, in particular bifidobacteria and lactobacilli, inhibition of pathogen adhesion and improvement of gut barrier function. GOS have attracted significant interest from food industries for their versatility as a bioactive ingredient and in particular as a functional component of infant formulations. These oligosaccharides are produced in a kinetically-controlled reaction involving lactose transgalactosylation, being catalyzed by particular β-galactosidases of bacterial or fungal origin. Despite the well-established technology applied for GOS production, this process may still meet with technological challenges when employed at an industrial scale. The current review will cover relevant scientific literature on the beneficial physiological properties of GOS as a prebiotic for the infant gut microbiota, details of GOS structures, the associated reaction mechanism of β-galactosidase, and its (large-scale) production.

Evaluation of an Infant Formula with Large, Milk-Phospholipid Coated Lipid Droplets on Long-Term Growth and Development of Singaporean Infants: Randomized Controlled Trial Protocol

A concept infant formula (IF) was developed with physical properties of lipid droplets mimicking more closely those in human milk. This paper describes the unique design of a randomised controlled trial evaluating the impact of the concept IF on infant growth and body composition development whilst applying a cohort-like recruitment approach that fully supports breastfeeding practices of the study population. Subjects entered the study between birth and 1 months of age, and whenever parents decided to introduce formula were randomised to one of three study formulas; the concept IF comprising large lipid droplets coated by milk phospholipids and containing a specific mixture of prebiotics, a standard IF with the specific prebiotic mixture or a standard IF without the prebiotic mixture. The primary objective was to evaluate the impact of the concept IF on growth and body composition outcomes during the first year of life with a follow-up at 2, 3, 4 and 5 years of age. In addition, stool, saliva and buccal smear samples and parameters assessing safety, gastrointestinal tolerance and cognitive outcomes were collected. The applied cohort-like enrolment approach is distinctly different from standard clinical safety or efficacy studies and may provide valuable insights on trial design for the evaluation of IF while carefully considering breastfeeding practices.

The Use of an Amino Acid Formula Containing Synbiotics in Infants with Cow's Milk Protein Allergy-Effect on Clinical Outcomes

Cow’s milk protein allergy (CMPA) is common and costly. Clinical trials of infants with CMPA have shown that the use of an amino acid formula containing pre- and probiotics (synbiotics) (AAF-Syn) may lead to significant reductions in infections, medication prescriptions and hospital admissions, compared to AAF without synbiotics. These effects have not yet been confirmed in real-world practice. This retrospective matched cohort study examined clinical and healthcare data from The Health Improvement Network database, from 148 infants with CMPA (54% male, mean age at diagnosis 4.69 months), prescribed either AAF-Syn (probiotic Bifidobacterium breve M16-V and prebiotics, including chicory-derived oligo-fructose and long-chain inulin) or AAF. AAF-Syn was associated with fewer symptoms (−37%, p < 0.001), infections (−35%, p < 0.001), medication prescriptions (−19%, p < 0.001) and healthcare contacts (−18%, p = 0.15) vs. AAF. Infants prescribed AAF-Syn had a significantly higher probability of achieving asymptomatic management without hypoallergenic formula (HAF) (adjusted HR 3.70, 95% CI 1.97–6.95, p < 0.001), with a shorter clinical course of symptoms (median time to asymptomatic management without HAF 1.35 years vs. 1.95 years). AAF-Syn was associated with potential cost-savings of £452.18 per infant over the clinical course of symptoms. These findings may be attributable to the effect of the specific synbiotic on the gut microbiome. Further research is warranted to explore this. This real-world study provides evidence consistent with clinical trials that AAF-Syn may produce clinical and healthcare benefits with potential economic impact.

A New Extracellular β-Galactosidase Producing Kluyveromyces sp. PCH397 from Yak Milk and Its Applications for Lactose Hydrolysis and Prebiotics Synthesis

β-Galactosidase is a crucial glycoside hydrolase enzyme with potential applications in the dairy, food, and pharmaceutical industries. The enzyme is produced in the intracellular environment by bacteria and yeast. The present study reports yeast Kluyveromyces sp. PCH397 isolated from yak milk, which has displayed extracellular β-galactosidase activity in cell-free supernatant through the growth phase. To investigate further, cell counting and methylene blue staining of culture collected at different growth stages were performed and suggested for possible autolysis or cell lysis, thereby releasing enzymes into the extracellular medium. The maximum enzyme production (9.94 ± 2.53U/ml) was achieved at 37 °C in a modified deMan, Rogosa, and Sharpe (MRS) medium supplemented with lactose (1.5%) as a carbon source. The enzyme showed activity at a wide temperature range (4-50 °C), maximum at 50 °C in neutral pH (7.0). In addition to the hydrolysis of lactose (5.0%), crude β-galactosidase also synthesized vital prebiotics (i.e., lactulose and galacto-oligosaccharides (GOS)). Additionally, β-fructofuranosidase (FFase) activity in the culture supernatant ensued the synthesis of a significant prebiotic, fructo-oligosaccharides (FOS). Hence, the unique features such as extracellular enzymes production, efficient lactose hydrolysis, and broad temperature functionality by yeast isolate PCH397 are of industrial relevance. In conclusion, the present study unrevealed for the first time, extracellular production of β-galactosidase from a new yeast source and its applications in milk lactose hydrolysis and synthesis of valuable prebiotics of industrial importance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-021-00955-1.

Strategies and Future Opportunities for the Prevention, Diagnosis, and Management of Cow Milk Allergy

The prevalence of food allergy has increased over the last 20-30 years, including cow milk allergy (CMA) which is one of the most common causes of infant food allergy. International allergy experts met in 2019 to discuss broad topics in allergy prevention and management of CMA including current challenges and future opportunities. The highlights of the meeting combined with recently published developments are presented here. Primary prevention of CMA should start from pre-pregnancy with a focus on a healthy lifestyle and food diversity to ensure adequate transfer of inhibitory IgG- allergen immune complexes across the placenta especially in mothers with a history of allergic diseases and planned c-section delivery. For non-breastfed infants, there is controversy about the preventive role of partially hydrolyzed formulae (pHF) despite some evidence of health economic benefits among those with a family history of allergy. Clinical management of CMA consists of secondary prevention with a focus on the development of early oral tolerance. The use of extensive Hydrolysate Formulae (eHF) is the nutrition of choice for the majority of non-breastfed infants with CMA; potentially with pre-, probiotics and LCPUFA to support early oral tolerance induction. Future opportunities are, among others, pre- and probiotics supplementation for mothers and high-risk infants for the primary prevention of CMA. A controlled prospective study implementing a step-down milk formulae ladder with various degrees of hydrolysate is proposed for food challenges and early development of oral tolerance. This provides a more precise gradation of milk protein exposure than those currently recommended.

Nutritional Interventions to Prevent the Development of Atopic Diseases: A Focus on Cow's Milk Allergy

In the western world the prevalence of atopic diseases such as food allergies is increasing highly significantly. One of the earliest and most prevalent food allergies occurring in the first year of life is cow's milk allergy. No treatment is available and only avoidance of the cow's milk allergens prevents the occurrence of an allergic reaction. Since cow's milk allergic children have an increased risk of developing other allergies later in life, investigating nutritional strategies to prevent the development of cow's milk allergy by developing oral tolerance is of high interest. Nutritional components such as prebiotics, probiotics, synbiotics and long-chain polyunsaturated fatty acids possess potential to support the maturation of the immune system early in life that might prevent the development of cow's milk allergy. The available research, so far, shows promising results particularly on the development of eczema. However, the preventive effects of the nutritional interventions on the development of food allergy are inconclusive. Future research may benefit from the combination of various dietary components. To clarify the preventive effects of the nutritional components in food allergy more randomized clinical trials are needed.

Bioactive Compounds in Infant Formula and Their Effects on Infant Nutrition and Health: A Systematic Literature Review

Infant formulas are an alternative to replace or supplement human milk when breastfeeding is not possible. The knowledge of human milk's bioactive compounds and their beneficial effects has attracted the interest of researchers in the field of infant nutrition, as well as researchers of technology and food sciences that seek to improve the nutritional characteristics of infant formulas. Several scientific studies evaluate the optimization of infant formula composition. The bioactive compound inclusion has been used to upgrade the quality and nutrition of infant formulas. In this context, the purpose of this systematic literature review is to assess the scientific evidence of bioactive compounds present in infant formulas (α-lactalbumin, lactoferrin, taurine, milk fat globule membrane, folates, polyamines, long-chain polyunsaturated fatty acids, prebiotics, and probiotics) and their effects on infant nutrition and health. Through previously determined criteria, studies published in the last fifteen years from five different databases were included to identify the advances in the optimization of infant formula composition. Over the last few years, there has been optimization of the infant formula composition, not only to increase the similarities in their content of macro and micronutrients but also to include novel bioactive ingredients with potential health benefits for infants. Although the infant food industry has advanced in the last years, there is no consensus on whether novel bioactive ingredients added to infant formulas have the same functional effects as the compounds found in human milk. Thus, further studies about the impact of bioactive compounds in infant nutrition are fundamental to infant health.

Halting the March: Primary Prevention of Atopic Dermatitis and Food Allergies

Atopic dermatitis (AD) is one of the most common inflammatory skin conditions, affecting 15% to 30% of children and 2% to 10% of adults. Population-based studies suggest that having AD is associated with subsequent development of other atopic diseases, in what is known as the "atopic march." We will provide an overview of studies that investigate primary prevention strategies for the first 2 diseases in the march, namely, AD and food allergies (FA). These strategies include emollients, breastfeeding, microbial exposures, probiotics, vitamin D and UV light, water hardness, and immunotherapy. Some studies, including randomized controlled trials on emollients and microbial supplementation, have found encouraging results; however, the evidence remains limited and contradictory. With regard to breastfeeding, microbial and lifestyle exposures, vitamin D and UV light, water hardness, and immunotherapy, the lack of randomized controlled trials makes it difficult to draw definitive conclusions. Current American Academy of Pediatrics guidelines support the idea that breastfeeding for 3 to 4 months can decrease AD incidence in children less than 2 years old. Recommendations regarding a direct relationship between breastfeeding on FA, however, cannot be made because of insufficient data. Regarding microbial supplementation, most guidelines do not recommend probiotics or prebiotics for the purpose of preventing allergic diseases because of limited evidence. Before definitive conclusions can be made regarding these interventions, more well-designed, longitudinal, and randomized controlled trials, particularly in at-risk populations, are required.

Long-Term Safety and Efficacy of Prebiotic Enriched Infant Formula-A Randomized Controlled Trial

The present study aims to evaluate the effects of an infant formula supplemented with a mixture of prebiotic short and long chain inulin-type oligosaccharides on health outcomes, safety and tolerance, as well as on fecal microbiota composition during the first year of life. In a prospective, multicenter, randomized, double-blind study, n = 160 healthy term infants under 4 months of age were randomized to receive either an infant formula enriched with 0.8 g/dL of Orafti^®Synergy1 or an unsupplemented control formula until the age of 12 months. Growth, fever (>38 °C) and infections were regularly followed up by a pediatrician. Digestive symptoms, stool consistency as well as crying and sleeping patterns were recorded during one week each study month. Fecal microbiota and immunological biomarkers were determined from a subgroup of infants after 2, 6 and 12 months of life. The intention to treat (ITT) population consisted of n = 149 infants. Both formulae were well tolerated. Mean duration of infections was significantly lower in the prebiotic fed infants (p < 0.05). The prebiotic group showed higher Bifidobacterium counts at month 6 (p = 0.006), and higher proportions of Bifidobacterium in relation to total bacteria at month 2 and 6 (p = 0.042 and p = 0.013, respectively). Stools of infants receiving the prebiotic formula were softer (p < 0.05). Orafti^®Synergy1 tended to beneficially impact total daily amount of crying (p = 0.0594). Supplementation with inulin-type prebiotic oligosaccharides during the first year of life beneficially modulates the infant gut microbiota towards higher Bifidobacterium levels at the first 6 months of life, and is associated with reduced duration of infections.

Novel and emerging prebiotics: Advances and opportunities

Consumers are conscientiously changing their eating preferences toward healthier options, such as functional foods enriched with pre- and probiotics. Prebiotics are attractive bioactive compounds with multidimensional beneficial action on both human and animal health, namely on the gastrointestinal tract, cardiometabolism, bones or mental health. Conventionally, prebiotics are non-digestible carbohydrates which generally present favorable organoleptic properties, temperature and acidic stability, and are considered interesting food ingredients. However, according to the current definition of prebiotics, application categories other than food are accepted, as well as non-carbohydrate substrates and bioactivity at extra-intestinal sites. Regulatory issues are considered a major concern for prebiotics since a clear understanding and application of these compounds among the consumers, regulators, scientists, suppliers or manufacturers, health-care providers and standards or recommendation-setting organizations are of utmost importance. Prebiotics can be divided in several categories according to their development and regulatory status. Inulin, galactooligosaccharides, fructooligosaccharides and lactulose are generally classified as well established prebiotics. Xylooligosaccharides, isomaltooligosaccharides, chitooligosaccharides and lactosucrose are classified as "emerging" prebiotics, while raffinose, neoagaro-oligosaccharides and epilactose are "under development." Other substances, such as human milk oligosaccharides, polyphenols, polyunsaturated fatty acids, proteins, protein hydrolysates and peptides are considered "new candidates." This chapter will encompass actual information about the non-established prebiotics, mainly their physicochemical properties, market, legislation, biological activity and possible applications. Generally, there is a lack of clear demonstrations about the effective health benefits associated with all the non-established prebiotics. Overcoming this limitation will undoubtedly increase the demand for these compounds and their market size will follow the consumer's trend.