Diet and food allergy development during infancy: Birth cohort study findings using prospective food diary data

Mechanisms of medicinal, pharmaceutical, and immunomodulatory action of probiotics bacteria and their secondary metabolites against disease management: an overview

Probiotics or bacteriotherapy is today's hot issue for public entities (Food and Agriculture Organization, and World Health Organization) as well as health and food industries since Metchnikoff and his colleagues hypothesized the correlation between probiotic consumption and human's health. They contribute to the newest and highly efficient arena of promising biotherapeutics. These are usually attractive in biomedical applications such as gut-related diseases like irritable bowel disease, diarrhea, gastrointestinal disorders, fungal infections, various allergies, parasitic and bacterial infections, viral diseases, and intestinal inflammation, and are also worth immunomodulation. The useful impact of probiotics is not limited to gut-related diseases alone. Still, these have proven benefits in various acute and chronic infectious diseases, like cancer, human immunodeficiency virus (HIV) diseases, and high serum cholesterol. Recently, different researchers have paid special attention to investigating biomedical applications of probiotics, but consolidated data regarding bacteriotherapy with a detailed mechanistically applied approach is scarce and controversial. The present article reviews the bio-interface of probiotic strains, mainly (i) why the demand for probiotics?, (ii) the current status of probiotics, (iii) an alternative to antibiotics, (iv) the potential applications towards disease management, (v) probiotics and industrialization, and (vi) futuristic approach.

Dietary Polyphenols, Plant Metabolites, and Allergic Disorders: A Comprehensive Review

Given the ongoing rise in the occurrence of allergic disorders, alterations in dietary patterns have been proposed as a possible factor contributing to the emergence and progression of these conditions. Currently, there is a significant focus on the development of dietary therapies that utilize natural compounds possessing anti-allergy properties. Dietary polyphenols and plant metabolites have been intensively researched due to their well-documented anti-inflammatory, antioxidant, and immunomodulatory characteristics, making them one of the most prominent natural bioactive chemicals. This study seeks to discuss the in-depth mechanisms by which these molecules may exert anti-allergic effects, namely through their capacity to diminish the allergenicity of proteins, modulate immune responses, and modify the composition of the gut microbiota. However, further investigation is required to fully understand these effects. This paper examines the existing evidence from experimental and clinical studies that supports the idea that different polyphenols, such as catechins, resveratrol, curcumin, quercetin, and others, can reduce allergic inflammation, relieve symptoms of food allergy, asthma, atopic dermatitis, and allergic rhinitis, and prevent the progression of the allergic immune response. In summary, dietary polyphenols and plant metabolites possess significant anti-allergic properties and can be utilized for developing both preventative and therapeutic strategies for targeting allergic conditions. The paper also discusses the constraints in investigating and broad usage of polyphenols, as well as potential avenues for future research.

Primary, secondary and tertiary prevention of food allergy: current practices and future directions

The incidence of food allergies has risen around the globe, and experts have been exploring methods of preventing such allergies in young children to ease the burden of disease and reduce the morbidity and mortality caused by anaphylaxis to food allergens. Such preventative measures can be categorised as primary, secondary and tertiary prevention, which are discussed in detail in this review. Primary prevention is defined as the prevention of becoming sensitised towards specific allergens. The evidence suggests that avoiding common allergenic foods during pregnancy and breastfeeding is not protective against food allergies, and guidelines recommend weaning from 4 to 6 months of age, with recent studies supporting the early introduction of peanuts at 4 months to prevent peanut allergy. Secondary prevention targets patients who are already sensitised and aims to halt the progression of sensitisation, with evidence for high rates of success and safety in trials of early introduction to milk and peanuts using oral immunotherapy in sensitised infants. Tertiary allergy prevention focuses on reducing the risk of a patient having anaphylaxis, with oral immunotherapy being the most common method of promoting tolerance in allergic children. Several studies have demonstrated successful reintroduction for milk, egg and peanut; however, no such guidelines are recommended for other foods. Finally, dietary advancement therapy in the form of milk and egg ladders has been employed as a method of primary, secondary and tertiary prevention of allergies, particularly in Ireland, the UK and Canada.

Diet Diversity During Infancy and the Prevalence of Sensitization and Allergy in Children up to 3 Years of Age in the Kujawsko-Pomorskie Voivodeship, Poland

The study examines the influence of a diversified diet, changes in the consistency of introduced foods, and the method of meal preparation during infancy on the development of sensitization and/or allergy in toddlers. Introducing more product groups into the diet reduced the risk of allergy at 6 months of age (adjusted odds ratio [aOR] = 0.17; 95% confidence interval [CI] 0.04-0.71; P = 0.015) and at 12 months (aOR = 0.14; 95% CI 0.03-0.57; P = 0.006). Children with allergy and/or sensitization had been introduced to fewer product groups at 6 months (P = 0.003; P < 0.001; P = 0.008) and at 12 months (P = 0.001, P < 0.001; P = 0.001) compared with those without allergy and/or sensitization. Children with allergy and/or sensitization were fed ready-made, ie, purchased, products significantly more often than self-prepared foods compared with children without allergy and/or sensitization (P = 0.001; P = 0.006). Allergic and/or sensitized children tended to be switched to solids later (11 vs 10 months, P = 0.041; P = 0.037) (12 vs 10 months, P = 0.013) than children without sensitization and/or allergy. The earlier introduction of a varied diet reduced the risk of allergy and/or sensitization. Delaying the introduction of solid foods and using ready-made products instead of self-prepared ones increases the risk of allergy in toddlers.

Effects of Early Diet on the Prevalence of Allergic Disease in Children: A Systematic Review and Meta-Analysis

Recent evidence suggests that the timing of introduction, types, and amounts of complementary foods/allergenic foods may influence the risk of allergic disease. However, the evidence has not been updated and comprehensively synthesized. The Cochrane Library, EMBASE, Web of Science, and PubMed databases were searched from the inception of each database up to 31 May 2023 (articles prior to 2000 were excluded manually). Statistical analyses were performed using RevMan 5. The GRADE approach was followed to rate the certainty of evidence. Compared with >6 mo, early introduction of eggs (≤6 mo of age) might reduce the risk of food allergies in preschoolers aged <6 y (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.53, 0.81), but had no effect on asthma or atopic dermatitis (AD). Consumption of fish at 6-12 mo might reduce the risk of asthma in children (aged 5-17 y) compared with late introduction after 12 mo (OR, 0.61; 95% CI: 0.52, 0.72). Introduction of allergenic foods for ≤6 mo of age, compared with >6 mos, was a protective factor for the future risk (children aged ≤10 y) of AD (OR, 0.93; 95% CI: 0.89, 0.97). Probiotic intervention for infants at high risk of allergic disease significantly reduced the risk of food allergy at ages 0-3 y (OR, 0.72; 95% CI: 0.56, 0.94), asthma at 6-12 y (OR, 0.61; 95% CI: 0.41, 0.90), and AD at aged <6 y (3-6 y: OR, 0.70; 95% CI: 0.52, 0.94; 0-3 y: OR, 0.73; 95% CI: 0.59, 0.91). Early introduction of complementary foods or the high-dose vitamin D supplementation in infancy was not associated with the risk of developing food allergies, asthma, or AD during childhood. Early introduction to potential allergen foods for normal infants or probiotics for infants at high risk of allergies may protect against development of allergic disease. This study was registered at PROSPERO as CRD42022379264.

Dietary Polyphenols-Natural Bioactive Compounds with Potential for Preventing and Treating Some Allergic Conditions

In light of the constantly increasing prevalence of allergic diseases, changes in dietary patterns have been suggested as a plausible environmental explanation for the development and progression of these diseases. Nowadays, much attention has been paid to the development of dietary interventions using natural substances with anti-allergy activities. In this respect, dietary polyphenols have been studied extensively as one of the most prominent natural bioactive compounds with well-documented anti-inflammatory, antioxidant, and immunomodulatory properties. This review aims to discuss the mechanisms underlying the potential anti-allergic actions of polyphenols related to their ability to reduce protein allergenicity, regulate immune response, and gut microbiome modification; however, these issues need to be elucidated in detail. This paper reviews the current evidence from experimental and clinical studies confirming that various polyphenols such as quercetin, curcumin, resveratrol, catechins, and many others could attenuate allergic inflammation, alleviate the symptoms of food allergy, asthma, and allergic rhinitis, and prevent the development of allergic immune response. Conclusively, dietary polyphenols are endowed with great anti-allergic potential and therefore could be used either for preventive approaches or therapeutic interventions in relation to allergic diseases. Limitations in studying and widespread use of polyphenols as well as future research directions are also discussed.

Environmental Exposure to Foods as a Risk Factor for Food Allergy

PURPOSE OF REVIEW

Many factors have been reported to contribute to the development of food allergy. Here, we summarize the role of environmental exposure to foods as a major risk factor for developing food allergy.

RECENT FINDINGS

Peanut proteins are detectable and biologically active in household environments, where infants spend a majority of their time, providing an environmental source of allergen exposure. Recent evidence from clinical studies and mouse models suggests both the airway and skin are routes of exposure that lead to peanut sensitization. Environmental exposure to peanut has been clearly associated with the development of peanut allergy, although other factors such as genetic predisposition, microbial exposures, and timing of oral feeding of allergens also likely contribute. Future studies should more comprehensively assess the contributions of each of these factors for a variety of food allergens to provide more clear targets for prevention of food allergy.

Differences in Self-Reported Food Allergy and Food-Associated Anaphylaxis by Race and Ethnicity Among SAPPHIRE Cohort Participants

BACKGROUND

Although food allergies are considered common, relatively little is known about disparities in food allergy by race in the United States.

OBJECTIVE

To evaluate differences in reported food allergy and food-associated anaphylaxis among individuals enrolled in a longitudinal cohort study from metropolitan Detroit, Michigan.

METHODS

Participants in the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-Ethnicity (SAPPHIRE) were asked about food allergies, including the inciting food and associated symptoms. Individuals were considered to have food-associated anaphylaxis if symptoms coincided with established clinical criteria. Logistic regression was used to assess whether race difference persisted after adjusting for and stratifying by potential confounders. African genetic ancestry was individually estimated among African American SAPPHIRE participants to assess whether ancestry was associated with food allergy.

RESULTS

Within the SAPPHIRE cohort, African American participants were significantly more likely to report food allergy (26.1% vs 17%; P = 3.47 × 10-18) and have food-associated anaphylactic symptoms (12.7% vs 7%; P = 4.65 × 10-14) when compared with European American participants. Allergy to seafood accounted for the largest difference (13.1% vs 4.6%; P = 1.38 × 10-31). Differences in food allergy by race persisted after adjusting for potential confounders including asthma status. Among African American participants, the proportion of African ancestry was not associated with any outcome evaluated.

CONCLUSION

Compared with European Americans, African Americans appear to be at higher risk for developing food allergy and food-associated anaphylaxis, particularly with regard to seafood allergy. The lack of association with genetic ancestry suggests that socioenvironmental determinants may play a role in these disparities.

Nutrition, Gut Microbiota, and Allergy Development in Infants

The process of gut microbiota development in infants is currently being challenged by numerous factors associated with the contemporary lifestyle, including diet. A thorough understanding of all aspects of microbiota development will be necessary for engineering strategies that can modulate it in a beneficial direction. The long-term consequences for human development and health of alterations in the succession pattern that forms the gut microbiota are just beginning to be explored and require much further investigation. Nevertheless, it is clear that gut microbiota development in infancy bears strong associations with the risk for allergic disease. A useful understanding of microbial succession in the gut of infants needs to reveal not only changes in taxonomic composition but also the development of functional capacities through time and how these are related to diet and various environmental factors. Metagenomic and metatranscriptomic studies have started to produce insights into the trends of functional repertoire and gene expression change within the first year after birth. This understanding is critical as during this period the most substantial development of the gut microbiota takes place and the relations between gut microbes and host immunity are established. However, further research needs to focus on the impact of diet on these changes and on how diet can be used to counteract the challenges posed by modern lifestyles to microbiota development and reduce the risk of allergic disease.

The External Exposome and Allergies: From the Perspective of the Epithelial Barrier Hypothesis

Introduction

In the last decades, we have seen a rapid increase in the prevalence of allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, and food allergies. The environmental changes caused by industrialization, urbanization and modernization, including dramatic increases in air pollutants such as particulate matter (PM), diesel exhaust, nitrogen dioxide (NO2), ozone (O3), alarming effects of global warming, change and loss of biodiversity, affect both human health and the entire ecosystem.

Objective

In this review, we aimed to discuss the effects of the external exposome on epithelial barriers and its relationship with the development of allergic diseases by considering the changes in all stakeholders of the outer exposome together, in the light of the recently proposed epithelial barrier hypothesis.

Method

To reach current, prominent, and comprehensive studies on the subject, PubMed databases were searched. We included the more resounding articles with reliable and strong results.

Results

Exposure to altered environmental factors such as increased pollution, microplastics, nanoparticles, tobacco smoke, food emulsifiers, detergents, and household cleaners, and climate change, loss and change in microbial biodiversity, modifications in the consumption of dietary fatty acids, the use of emulsifiers, preservatives and the decrease in the antioxidant content of the widely consumed western diet may disrupt the epithelial barriers of the skin, respiratory and gastrointestinal tracts, making us more vulnerable to exogeneous allergens and microbes. Epithelial cell activation, microbial dysbiosis and bacterial translocation disrupt the immune balance and a chronic Th2 inflammation ensues.

Conclusion

Dramatic increases in air pollution, worrisome effects of global warming, dysbiosis, changing dietary habits and the complex interactions of all these factors affect the epithelial barriers and local and systemic inflammation. We want to draw attention to the emerging health effects of environmental changes and to motivate the public to influence government policies for the well-being of humans and the nature of the earth and the well-being of future generations.

Epithelial barrier hypothesis: Effect of the external exposome on the microbiome and epithelial barriers in allergic disease

Environmental exposure plays a major role in the development of allergic diseases. The exposome can be classified into internal (e.g., aging, hormones, and metabolic processes), specific external (e.g., chemical pollutants or lifestyle factors), and general external (e.g., broader socioeconomic and psychological contexts) domains, all of which are interrelated. All the factors we are exposed to, from the moment of conception to death, are part of the external exposome. Several hundreds of thousands of new chemicals have been introduced in modern life without our having a full understanding of their toxic health effects and ways to mitigate these effects. Climate change, air pollution, microplastics, tobacco smoke, changes and loss of biodiversity, alterations in dietary habits, and the microbiome due to modernization, urbanization, and globalization constitute our surrounding environment and external exposome. Some of these factors disrupt the epithelial barriers of the skin and mucosal surfaces, and these disruptions have been linked in the last few decades to the increasing prevalence and severity of allergic and inflammatory diseases such as atopic dermatitis, food allergy, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis, and asthma. The epithelial barrier hypothesis provides a mechanistic explanation of how these factors can explain the rapid increase in allergic and autoimmune diseases. In this review, we discuss factors affecting the planet's health in the context of the 'epithelial barrier hypothesis,' including climate change, pollution, changes and loss of biodiversity, and emphasize the changes in the external exposome in the last few decades and their effects on allergic diseases. In addition, the roles of increased dietary fatty acid consumption and environmental substances (detergents, airborne pollen, ozone, microplastics, nanoparticles, and tobacco) affecting epithelial barriers are discussed. Considering the emerging data from recent studies, we suggest stringent governmental regulations, global policy adjustments, patient education, and the establishment of individualized control measures to mitigate environmental threats and decrease allergic disease.

Nutrition during Pregnancy and Lactation: Epigenetic Effects on Infants’ Immune System in Food Allergy

Food allergies are an increasing health problem worldwide. They are multifactorial diseases, in which the genome alone does not explain the development of the disease, but a genetic predisposition and various environmental factors contribute to their onset. Environmental factors, in particular nutritional factors, in the early stages of life are recognized as key elements in the etiology of food allergies. There is growing evidence advising that nutrition can affect the risk of developing food allergies through epigenetic mechanisms elicited by the nutritional factors themselves or by modulating the gut microbiota and its functional products. Gut microbiota and postbiotics can in turn influence the risk of food allergy development through epigenetic mechanisms. Epigenetic programming accounts not only for the short-term effects on the individual’s health status, but also for those observed in adulthood. The first thousand days of life represent an important window of susceptibility in which environmental factors, including nutritional ones, can influence the risk of developing allergies through epigenetic mechanisms. From this point of view, it represents an interesting window of opportunity and intervention. This review reports the main nutritional factors that in the early stages of life can influence immune oral tolerance through the modulation of epigenetic mechanisms.

The Foetal Origins of Allergy and Potential Nutritional Interventions to Prevent Disease

The first nine months from conception to birth involves greater changes than at any other time in life, affecting organogenesis, endocrine, metabolic and immune programming. It has led to the concept that the “first 1000 days” from conception to the second birthday are critical in establishing long term health or susceptibility to disease. Immune ontogeny is predominantly complete within that time and is influenced by the maternal genome, health, diet and environment pre-conception and during pregnancy and lactation. Components of the immunological protection of the pregnancy is the generation of Th-2 and T-regulatory cytokines with the consequence that neonatal adaptive responses are also biased towards Th-2 (allergy promoting) and T-regulatory (tolerance promoting) responses. Normally after birth Th-1 activity increases while Th-2 down-regulates and the evolving normal human microbiome likely plays a key role. This in turn will have been affected by maternal health, diet, exposure to antibiotics, mode of delivery, and breast or cow milk formula feeding. Complex gene/environment interactions affect outcomes. Many individual nutrients affect immune mechanisms and variations in levels have been associated with susceptibility to allergic disease. However, intervention trials employing single nutrient supplementation to prevent allergic disease have not achieved the expected outcomes suggested by observational studies. Investigation of overall dietary practices including fresh fruit and vegetables, fish, olive oil, lower meat intake and home cooked foods as seen in the Mediterranean and other healthy diets have been associated with reduced prevalence of allergic disease. This suggests that the “soup” of overall nutrition is more important than individual nutrients and requires further investigation both during pregnancy and after the infant has been weaned. Amongst all the potential factors affecting allergy outcomes, modification of maternal and infant nutrition and the microbiome are easier to employ than changing other aspects of the environment but require large controlled trials before recommending changes to current practice.

Evaluation of Stool Short Chain Fatty Acids Profiles in the First Year of Life With Childhood Atopy-Related Outcomes

Introduction

Short chain fatty acids (SCFAs) are the main intestinal intermediate and end products of metabolism of dietary fibers/polyphenols by the gut microbiota. The aim of this study was to evaluate the biological implication of stool SCFA profiles determined in the first year of life on the clinical presentation of allergic outcomes in childhood.

Methods

From the Growing Up in Singapore Toward healthy Outcomes (GUSTO) cohort, a sub-cohort of 75 participants was recruited. Scheduled questionnaire data was collected for cumulative prevalence of physician-diagnosed eczema, wheezing with the use of nebuliser, and allergen sensitization till the age of 8 years. Stool samples collected at week 3 and months 3, 6 and 12 were quantitated for 9 SCFAs using LC/MS/MS. SCFA data were grouped into lower (below the 25th⁾ and higher (above the 75th percentiles) categories. Generalized Linear Mixed Models was employed to analyse longitudinal association between SCFAs and atopy-related outcomes.

Results

Children with lower stool butyric acid levels (≤25th percentile) over the first 3 time points had higher odds ratio (OR) for wheezing (adjOR = 14.6), eczema (adjOR = 13.2), food sensitization (adjOR = 12.3) and combined outcomes of both wheezing and eczema (adjOR = 22.6) till age 8 years, compared to those with higher levels (≥75 percentile). Additionally, lower longitudinal levels of propionic acid (≤25th percentile) over 4 time points in first year of life was associated with recurrent wheezing (≥2 episodes) till 8 years (adjOR = 7.4) (adj p < 0.05).

Conclusion

Our results suggest that relatively low levels of gut SCFAs in early life are associated with increased susceptibility to atopic-related outcomes in childhood.

Early intervention and prevention of allergic diseases

Food allergy (FA) is now one of the most common chronic diseases of childhood often lasting throughout life and leading to significant worldwide healthcare burden. The precise mechanisms responsible for the development of this inflammatory condition are largely unknown; however, a multifactorial aetiology involving both environmental and genetic contributions is well accepted. A precise understanding of the pathogenesis of FA is an essential first step to developing comprehensive prevention strategies that could mitigate this epidemic. As it is frequently preceded by atopic dermatitis and can be prevented by early antigen introduction, the development of FA is likely facilitated by the improper initial presentation of antigen to the developing immune system. Primary oral exposure of antigens allowing for presentation via a well-developed mucosal immune system, rather than through a disrupted skin epidermal barrier, is essential to prevent FA. In this review, we present the data supporting the necessity of (1) an intact epidermal barrier to prevent epicutaneous antigen presentation, (2) the presence of specific commensal bacteria to maintain an intact mucosal immune system and (3) maternal/infant diet diversity, including vitamins and minerals, and appropriately timed allergenic food introduction to prevent FA.

Lycopene intake induces colonic regulatory T cells in mice and suppresses food allergy symptoms

BACKGROUND

Food allergy (FA) is a common disease in children; thus, a high level of safety is required for its prevention and treatment. Colonic regulatory T cells (Tregs) have been suggested to attenuate FA. We investigated the Treg-inducing ability and anti-FA effects of carotenoids, a pigment contained in vegetables and fruits.

METHODS

C57BL/6N mice were fed a diet containing 0.01% (w/w) of lycopene, β-carotene, astaxanthin or lutein for 4 weeks, and the population of colonic Tregs was assessed. Subsequently, to evaluate the Treg-inducing ability of lycopene, splenic naïve CD4⁺ T cells from BALB/c mice were cultured with anti-CD3/CD28 antibody, TGF-β and lycopene, and the frequencies of Tregs were examined. The effect of 0.1% (w/w) lycopene containing diet on FA was investigated in OVA-induced FA model BALB/c mice.

RESULTS

In screening, only lycopene significantly increased the frequency and number of colonic Tregs. Lycopene also increased Treg differentiation in splenic naïve CD4⁺ T cells. In FA mice, lycopene feeding significantly increased the number of colonic Tregs and attenuated allergic symptoms. The expression levels of IL-4, IL-9 and IL-13 mRNA in colonic mucosa were also significantly reduced by lycopene. IL-9 is known to induce proliferation of mast cells, and we found that lycopene feeding significantly reduced the number of mast cells in the colonic mucosa of FA mice.

CONCLUSION

Our results suggest that lycopene, a carotenoid present in many common foods on the market, may have the potential to induce colonic Tregs and suppress FA symptoms.

Influence of Diet on the Effect of the Probiotic Lactobacillus paracasei in Rats Suffering From Allergic Asthma

Mounting evidence suggests that probiotics can be used to treat allergic asthma by modulating the gut microbiota, and that the effects of probiotics may be influenced by environmental factors such as diet. We conducted a rat model with allergic asthma (AA) modulated by Lactobacillus paracasei, feeding up with high-fat or high-fiber diets based on collecting data from 85 questionnaires. The systemic proinflammatory cytokines were detected by ELISA and the overall structure of fecal microbiota was analyzed via 16S rRNA gene sequencing. The results showed consumption of a high-fiber diet alleviated the allergic symptoms and airway inflammation, and led to improving the imbalance of T-helper type 1 (Th1)/Th2 cells with increased expression of interferon-γ and decreased expression of interleukin-4. Whereas, the high-fat diet had deteriorating implications and skewed the inflammatory perturbation. Furthermore, abundances of phylum Bacteroidetes, families Muribaculaceae, Tannerellaceae, Prevotellaceae, Enterococcaceae, genera Allobaculum, Parabacteroides, and Enterococcus were enriched in L. paracasei-modulating rats fed with high-fiber diet. Firmicutes and Proteobacteria, families Lachnospiraceae, Ruminococcaceae and Desulfovibrionaceae, genera Blautia, unidentified_Ruminococcaceae, unidentified_Clostridiales and Oscillibacter were in relatively high abundance in the rats administered high-fat diet. Association between changed microbiota and inflammatory cytokines was also conferred. These data indicated that the efficacy of L. paracasei in allergic asthma was influenced by different dietary patterns. Hence, diet is important for probiotic therapy when managing allergic asthma.

Inverse associations between food diversity in the second year of life and allergic diseases

BACKGROUND

The influence of diet in early childhood on later allergic diseases is currently a highly debated research topic. We and others have suggested that an increased diet diversity in the first year of life has a protective effect on the development of allergic diseases.

OBJECTIVE

This follow-up study aimed to investigate associations between diet in the second year of life and later allergic diseases.

METHODS

A total of 1014 children from rural areas in 5 European countries (the Protection against Allergy: Study in Rural Environments or PASTURE birth cohort) were included. Information on feeding practices in their second year of life and allergic diseases were collected up to age 6 years. Multivariate logistic regressions were performed with different models considering reverse causality, such as excluding children with a positive sensitization to egg and those with a positive sensitization to cow's milk at the age of 1 year.

RESULTS

An increased food diversity score during the second year of life was negatively associated with the development of asthma. Consumption of dairy products and eggs in the second year of life found an inverse association with reported allergic outcomes. Consumption of butter was strongly associated with protection against asthma and food sensitization. Egg was inversely associated with atopic dermatitis (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.04-0.77). Yogurt and cow's milk were inversely associated with food allergy (OR for yogurt, 0.05; 95% CI, 0.01-0.55; OR for cow's milk, 0.31; 95% CI, 0.11-0.89).

CONCLUSION

Increased food diversity in the second year of life is inversely associated with the development of asthma, and consumption of dairy products might have a protective effect on allergic diseases.

Primary Prevention of Food Allergy-Environmental Protection beyond Diet

A food allergy is a potentially life-threatening disease with a genetic and environmental background. As its prevalence has increased significantly in recent years, the need for its effective prevention has been emphasized. The role of diet modifications and nutrients in food allergy reduction has been extensively studied. Much less is known about the role of other environmental factors, which can influence the incidence of this disease. Changes in neonates gut microbiome by delivery mode, animal contact, inhalant allergens, oral and then cutaneous allergen exposure, air pollution, smoking, infections and vaccinations can be the potential modifiers of food allergy development. There is some data about their role as the risk or preventive factors, but yet the results are not entirely consistent. In this paper we present the current knowledge about their possible role in primary prevention of food allergies. We discuss the mechanisms of action, difficulties in designing accurate studies about food allergy and the potential biases in interpreting the connection between environmental factors and food allergy prevention. A better understanding of the role of environmental factors in food allergies development may help in implementing practical solutions for food allergy primary prevention in the future.

Butyrate: A Link between Early Life Nutrition and Gut Microbiome in the Development of Food Allergy

Increased prevalence of food allergies in the last thirty years has been attributed to lifestyle changes in Westernized countries. Among the environmental factors, nutritional factors and their interaction with the gut microbiome in early life are thought to have an important role in the observed epidemiological change. The gut microbiome synthesizes bacterial metabolites, which represent a link among gut microbiome, nutrition, and immune system. The main metabolites produced by gut microbiome are short-chain fatty acids (SCFAs). SCFAs have multiple beneficial effects on human health including protective effects in autoimmune and inflammatory diseases. Among SCFAs, butyrate is essential for maintaining gut immune homeostasis and exerts a pivotal role in immune tolerance with strong anti-inflammatory effects in allergic diseases. Recent findings suggest that butyrate takes part in the development of immunological tolerance to food, especially in the first 1000 days of life. Herein, we provide a critical review of the scientific literature on the role of butyrate for prevention and treatment of food allergies with focus on the complex interplay among early life nutrition, gut microbiome, and immune system.

Recipe Components and Parents' Infant and Young Child Feeding Concerns: A Mixed-Methods Study of Recipe Posts Shared in Thai Facebook Groups for Parents

Social media is increasingly becoming a significant source of information for parents, including about feeding young children. However, little attention has been given to the characteristics of recipes for infants and young children and how they interact with parental perceptions regarding food decisions shared by users on social media. Building on findings related to shared recipe components and parental food choices, between December 2019 and July 2020, this study retrospectively collected 80 shared recipes each from five Thai Facebook groups. This extraction created 379 shared recipes with 1751 peers’ commentaries on the shared recipes’ posts. The shared recipes were classified and components quantified across child age groups, then the textual contents around the reasons behind the food choices were described qualitatively. The results showed that there were differences in meal types, food ingredients, and seasoning used across child age groups. Further analysis found that food allergy awareness was one driving concern behind parental perceptions on food choices in children’s diets. These concerns resulted in delays in the introduction of animal-source foods. Moreover, peers’ commentaries on shared recipes offered a venue for exchanging experiences with food products. Because of the potential influence on parental beliefs and perceptions, further studies are required to understand the impact of existing online communities on actual feeding practices.

The Infant Microbiome and Its Impact on Development of Food Allergy

The prevalence of food allergy (FA) has been increasing over the past few decades; recent statistics suggest that FA has an impact on up to 10% of the population and 8% of children. Although the pathogenesis of FA is unclear, studies suggest gut microbiome plays a role in the development of FA. The gut microbiome is influenced by infant feeding method, infant diet, and maternal diet during lactation. Breastfeeding, Mediterranean diet, and probiotics are associated with commensal gut microbiota that protect against FA. This area of research is essential to discovering potential preventive methods or therapeutic targets against FA.

Allergy Prevention: An Overview of Current Evidence

Background: There has been a rapid rise in allergic disorders across the globe. This has increased research into the determinants of allergy development, to identify factors that may be manipulated to mitigate risk. An opportune window in immunological development appears to exist in early life whereby certain exposures may promote or prevent the development of an allergic disposition. Furthermore, factors that affect the composition and diversity of the microbiome in early life have been explored. In this review, we discuss current literature and recommendations relating to exposures that may prevent allergy development or promote tolerance. Risk factors and recommendations: Delivery by caesarean section, omission of breastfeeding, vitamin D insufficiency, and environmental exposures, such as cigarette smoke exposure, all increase the risk of an allergic predisposition. Dietary diversity during pregnancy, lactation, and in infancy is protective. Breastfeeding for at least 4 months reduces the risk of eczema. Recommendations for food-allergen exposure has shifted from delayed introduction to early introduction as a tolerance-inducing strategy. Supplements such as probiotics and vitamins during pregnancy and infancy have yet to produce conclusive results for allergy prevention. Emollient use in infancy has not been shown to be protective against eczema or food allergy.

A Consensus Approach to the Primary Prevention of Food Allergy Through Nutrition: Guidance from the American Academy of Allergy, Asthma, and Immunology; American College of Allergy, Asthma, and Immunology; and the Canadian Society for Allergy and Clinical Immunology

Recently published data from high-impact randomized controlled trials indicate the strong potential of strategies to prevent the development of food allergy in high-risk individuals, but guidance in the United States at present is limited to a policy for only the prevention of peanut allergy, despite other data being available and several other countries advocating early egg and peanut introduction. Eczema is considered the highest risk factor for developing IgE-mediated food allergy, but children without risk factors still develop food allergy. To prevent peanut and/or egg allergy, both peanut and egg should be introduced around 6 months of life, but not before 4 months. Screening before introduction is not required, but may be preferred by some families. Other allergens should be introduced around this time as well. Upon introducing complementary foods, infants should be fed a diverse diet, because this may help foster prevention of food allergy. There is no protective benefit from the use of hydrolyzed formula in the first year of life against food allergy or food sensitization. Maternal exclusion of common allergens during pregnancy and/or lactation as a means to prevent food allergy is not recommended. Although exclusive breast-feeding is universally recommended for all mothers, there is no specific association between exclusive breast-feeding and the primary prevention of any specific food allergy.

EAACI position paper on diet diversity in pregnancy, infancy and childhood: Novel concepts and implications for studies in allergy and asthma

To fully understand the role of diet diversity on allergy outcomes and to set standards for conducting research in this field, the European Academy of Allergy and Clinical Immunology Task Force on Diet and Immunomodulation has systematically explored the association between diet diversity and allergy outcomes. In addition, a detailed narrative review of information on diet quality and diet patterns as they pertain to allergic outcomes is presented. Overall, we recommend that infants of any risk category for allergic disease should have a diverse diet, given no evidence of harm and some potential association of benefit in the prevention of particular allergic outcomes. In order to harmonize methods for future data collection and reporting, the task force members propose relevant definitions and important factors for consideration, when measuring diet diversity in the context of allergy. Consensus was achieved on practice points through the Delphi method. It is hoped that the definitions and considerations described herein will also enable better comparison of future studies and improve mechanistic studies and pathway analysis to understand how diet diversity modulates allergic outcomes.

Different Measures of Diet Diversity During Infancy and the Association with Childhood Food Allergy in a UK Birth Cohort Study

BACKGROUND

Diet diversity (DD) during infancy may prevent food allergies (FA), possibly by exposing the gastrointestinal microbiota to diverse foods and nutrients.

OBJECTIVE

To investigate the association between 4 different measures of DD during infancy and development of FA over the first decade of life.

METHODS

A birth cohort born between 2001 and 2002 were followed prospectively, providing information on sociodemographic, environmental, and dietary exposures. Information on age of introduction of a range of foods and food allergens was collected during infancy. Children were assessed for FA at 1, 2, 3, and 10 years. DD was defined using 4 measures in the first year of life: the World Health Organization definition of minimum DD at 6 months, as food diversity (FD) and fruit and vegetable diversity (FVD) at 3, 6, and 9 months, and as food allergen diversity (FAD) at 3, 6, 9, and 12 months.

RESULTS

A total of 969 pregnant women were recruited at 12-week gestation. A total of 900, 858, 891, and 827 offspring were assessed at 1, 2, 3, and 10 years. Univariate analysis showed that World Health Organization DD (P = .0047), FD (P = .0009), FAD (P = .0048), and FVD (P = .0174) at 6 months and FD (P = .0392), FAD (P = .0233), and FVD (.0163) at 9 months significantly reduced the odds of FA over the first decade of life. DD measures at 3 months were not associated with FA, but only 33% of the cohort had solid foods introduced by this age.

CONCLUSION

Increased infant DD, as measured by 4 different methods, decreased the likelihood of developing FA.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

Microbial interactions in the atopic march

The human body is populated by a large number of microorganisms and exist in symbiosis with these immensely diverse communities, which are suggested to influence health and disease. The microbiota plays an essential role in the maturation and function of the immune system. The prevalence of atopic diseases has increased drastically over the past decades, and the co-occurrence of multiple allergic diseases and allergic sensitization starting in early life has gained a great deal of attention. Immune responses in different organs affected by allergic diseases (e.g. skin, intestine and lung) may be linked to microbial changes in peripheral tissues. In the current review, we provide an overview of the current understanding of microbial interactions in allergic diseases and their potential role in the atopic march.

Long Chain Polyunsaturated Fatty Acids (LCPUFAs) in the Prevention of Food Allergy

N-3 long chain polyunsaturated fatty acids (LCPUFAs) are considered to possess protective properties for human health by impacting on immunological reactions. An “inflammation-suppressive” effect appears to be the common denominator of the beneficial effects of most of these dietary components which may protect against the development of chronic immune disorders such as (food) allergy. LCPUFAs, especially n-3 LCPUFAs, have been shown to interact with both the sensitization as well as the effector phase in food allergy in pre-clinical models. In this review, we explore the anti-allergic properties of LCPUFAs by providing an overview of clinical, in vivo and in vitro studies. Furthermore, we discuss the susceptibility of LCPUFAs to lipid oxidation and possible strategies to support the efficacy of LCPUFAs in reducing the allergy risk by using additional components with anti-oxidative and anti-inflammatory capacities such as the flavonoid quercetin. Finally, we propose new strategies to prevent (food) allergy using combinations of LCPUFAs and additional nutrients in diets or supplements, and postulate to investigate the use of LCPUFAs in allergic symptom relief.

Complementary feeding and food allergy, atopic dermatitis/eczema, asthma, and allergic rhinitis: a systematic review

BACKGROUND

Nutrition during infancy and toddlerhood may influence health and disease prevention across the life span. Complementary feeding (CF) starts when human milk or infant formula is complemented by other foods and beverages, beginning during infancy and continuing to age 24 mo.

OBJECTIVES

The aim of this study was to describe systematic reviews conducted for the USDA and the Department of Health and Human Services Pregnancy and Birth to 24 Months Project to answer the following question: What is the relationship between the timing of the introduction of complementary foods and beverages (CFBs), or types and amounts of CFBs consumed, and the development of food allergy, atopic dermatitis/eczema, asthma, and allergic rhinitis?

METHODS

The literature was searched using 4 databases (CINAHL, Cochrane, Embase, PubMed) to identify articles published from January 1980 to February 2017 that met predetermined inclusion criteria. For each study, data were extracted and risk of bias was assessed. The evidence was qualitatively synthesized to develop a conclusion statement, and the strength of the evidence was graded.

RESULTS

Thirty-one included articles addressed the timing of CFB introduction, and 47 articles addressed the types and amounts of CFBs consumed.

CONCLUSIONS

Moderate evidence suggests that there is no relationship between the age at which CF first begins and the risk of developing food allergy, atopic dermatitis/eczema, or childhood asthma. Limited to strong evidence, depending on the specific food, suggests that introducing allergenic foods in the first year of life (after 4 mo) does not increase the risk of food allergy and atopic dermatitis/eczema but may prevent peanut and egg allergy. There is not enough evidence to determine a relationship between diet diversity or dietary patterns and atopic disease. Research is needed to address gaps and limitations in the evidence on CF and atopic disease, including research that uses valid and reliable diagnostic measures and accounts for key confounders and potential reverse causality.

Gut Microbiome as Target for Innovative Strategies Against Food Allergy

The dramatic increase in food allergy prevalence and severity globally requires effective strategies. Food allergy derives from a defect in immune tolerance mechanisms. Immune tolerance is modulated by gut microbiota function and structure, and microbiome alterations (dysbiosis) have a pivotal role in the development of food allergy. Environmental factors, including a low-fiber/high-fat diet, cesarean delivery, antiseptic agents, lack of breastfeeding, and drugs can induce gut microbiome dysbiosis, and have been associated with food allergy. New experimental tools and technologies have provided information regarding the role of metabolites generated from dietary nutrients and selected probiotic strains that could act on immune tolerance mechanisms. The mechanisms are multiple and still not completely defined. Increasing evidence has provided useful information on optimal bacterial species/strains, dosage, and timing for intervention. The increased knowledge of the crucial role played by nutrients and gut microbiota-derived metabolites is opening the way to a post-biotic approach in the stimulation of immune tolerance through epigenetic regulation. This review focused on the potential role of gut microbiome as the target for innovative strategies against food allergy.

Microbiome and Allergic Diseases

Allergic diseases, such as respiratory, cutaneous, and food allergy, have dramatically increased in prevalence over the last few decades. Recent research points to a central role of the microbiome, which is highly influenced by multiple environmental and dietary factors. It is well established that the microbiome can modulate the immune response, from cellular development to organ and tissue formation exerting its effects through multiple interactions with both the innate and acquired branches of the immune system. It has been described at some extent changes in environment and nutrition produce dysbiosis in the gut but also in the skin, and lung microbiome, inducing qualitative and quantitative changes in composition and metabolic activity. Here, we review the potential role of the skin, respiratory, and gastrointestinal tract (GIT) microbiomes in allergic diseases. In the GIT, the microbiome has been proven to be important in developing either effector or tolerant responses to different antigens by balancing the activities of Th1 and Th2 cells. In the lung, the microbiome may play a role in driving asthma endotype polarization, by adjusting the balance between Th2 and Th17 patterns. Bacterial dysbiosis is associated with chronic inflammatory disorders of the skin, such as atopic dermatitis and psoriasis. Thus, the microbiome can be considered a therapeutical target for treating inflammatory diseases, such as allergy. Despite some limitations, interventions with probiotics, prebiotics, and/or synbiotics seem promising for the development of a preventive therapy by restoring altered microbiome functionality, or as an adjuvant in specific immunotherapy.

The nutrition-gut microbiome-physiology axis and allergic diseases

Dietary and bacterial metabolites influence immune responses. This raises the question whether the increased incidence of allergies, asthma, some autoimmune diseases, cardiovascular disease, and others might relate to intake of unhealthy foods, and the decreased intake of dietary fiber. In recent years, new knowledge on the molecular mechanisms underpinning a 'diet-gut microbiota-physiology axis' has emerged to substantiate this idea. Fiber is fermented to short chain fatty acids (SCFAs), particularly acetate, butyrate, and propionate. These metabolites bind 'metabolite-sensing' G-protein-coupled receptors such as GPR43, GPR41, and GPR109A. These receptors play fundamental roles in the promotion of gut homeostasis and the regulation of inflammatory responses. For instance, these receptors and their metabolites influence Treg biology, epithelial integrity, gut homeostasis, DC biology, and IgA antibody responses. The SCFAs also influence gene transcription in many cells and tissues, through their inhibition of histone deacetylase expression or function. Contained in this mix is the gut microbiome, as commensal bacteria in the gut have the necessary enzymes to digest dietary fiber to SCFAs, and dysbiosis in the gut may affect the production of SCFAs and their distribution to tissues throughout the body. SCFAs can epigenetically modify DNA, and so may be one mechanism to account for diseases with a 'developmental origin', whereby in utero or post-natal exposure to environmental factors (such as nutrition of the mother) may account for disease later in life. If the nutrition-gut microbiome-physiology axis does underpin at least some of the Western lifestyle influence on asthma and allergies, then there is tremendous scope to correct this with healthy foodstuffs, probiotics, and prebiotics.

Regulatory Immune Mechanisms in Tolerance to Food Allergy

Oral tolerance can develop after frequent exposure to food allergens. Upon ingestion, food is digested into small protein fragments in the gastrointestinal tract. Small food particles are later absorbed into the human body. Interestingly, some of these ingested food proteins can cause allergic immune responses, which can lead to food allergy. So far it has not been completely elucidated how these proteins become immunogenic and cause food allergies. In contrast, oral tolerance helps to prevent the pathologic reactions against different types of food antigens from animal or plant origin. Tolerance to food is mainly acquired by dendritic cells, epithelial cells in the gut, and the gut microbiome. A subset of CD103⁺ DCs is capable of inducing T regulatory cells (Treg cells) that express anti-inflammatory cytokines. Anergic T cells also contribute to oral tolerance, by reducing the number of effector cells. Similar to Treg cells, B regulatory cells (Breg cells) suppress effector T cells and contribute to the immune tolerance to food allergens. Furthermore, the human microbiome is an essential mediator in the induction of oral tolerance or food allergy. In this review, we outline the current understanding of regulatory immune mechanisms in oral tolerance. The biological changes reflecting early consequences of immune stimulation with food allergens should provide useful information for the development of novel therapeutic treatments.

Fruit intake reduces the onset of respiratory allergic symptoms in schoolchildren

BACKGROUND

Previous studies have shown that dietary pattern is associated with allergy prevention.

METHODS

We conducted a prospective cohort study on all primary schools in Omihachiman City, Shiga Prefecture, Japan. Questionnaires regarding allergic symptoms and diet were distributed to the parents of all 759 7-year-old schoolchildren for 4 consecutive years, from 2011 to 2014. Specific immunoglobulin E to inhalant allergens was measured at 10 years of age. Participants were then categorized as low, medium, or high intake during the study period for four food groups (fruits, vegetables, fish, and beans). Logistic regression analysis was performed to estimate odds ratios and 95% confidence intervals.

RESULTS

A total of 520 children (68.5%) whose parents responded to the questionnaires all 4 years were included in the analysis. The prevalence of asthma, rhinitis, and any allergic symptoms at age 10 was significantly decreased with increases in fruit intake. In addition, the onset of any allergic symptoms during the study period was significantly decreased with increases in fruit intake (33.3%, 28.3%, and 14.3% in children with low, medium, and high fruit intake, respectively; P for trend =.01). The sensitization rate to ragweed at age 10 was significantly decreased with increases in fruit intake (P for trend =.046). No significant effect was observed for the other three food groups, except for the association between fish intake and new-onset asthma symptoms.

CONCLUSIONS

These findings suggest that higher intake of fruit can help prevent respiratory allergic symptoms in schoolchildren.

Gut microbiota in early life and its influence on health and disease: A position paper by the Malaysian Working Group on Gastrointestinal Health

The role of gut microbiota in early life and its impact on gut health and subsequent diseases remain unclear. There is a lack of research and awareness in this area, especially in the Asia-Pacific region, including Malaysia. This paper reports the position of a Malaysian Working Group on some key issues surrounding gut microbiota in early life and its role in gut health and diseases, as well as experts' stand on probiotics and prebiotics. The group reached a consensus that certain factors, including elective caesarean; premature deliveries; complementary feeding; use of antibiotics, prebiotics and/or probiotics; and exposure to the external environmental, have an impact on gut microbiota in early life. However, as evidence is lacking, especially from the Asia-Pacific region, further studies are needed to understand how gut microbiota in early life affects subsequent diseases, including allergy, inflammatory bowel disease, obesity and infantile colic. Lastly, although beneficial in acute diarrhoeal disease and probably allergic eczema, probiotics (and/or prebiotics) should be used cautiously in other gut dysbiotic conditions until more data are available.

Introducing Allergenic Food into Infants' Diets: Systematic Review

PURPOSE

The purpose of this systematic review was to explore the association between timing of introduction of potentially allergenic foods to infants and development of food allergies.

METHODS

CINAHL, Medline, PubMed, Science Direct, and Web of Science were searched using the terms solid food, complementary food, or infant feeding combined with allergy or hypersensitivity for articles published in English in 2000 or later. Inclusion criteria were 1) primary research articles with 2) a focus on association between introduction of complementary foods including potentially allergenic foods into diets of infants less than 12 months of age and development of food allergies. Articles were excluded if they were 1) not primary research, 2) about complementary foods only (without specificity of allergenic foods), or 3) on allergic conditions other than food allergy (such as asthma or eczema).

RESULTS

The initial literature search yielded 533 articles; 14 articles met inclusion criteria. Level of evidence of each study was determined with the SORT criteria. Results found that delayed introduction of solid foods in general and allergenic foods in particular was not associated with decreased risk for allergic diseases among high and low-risk infants. Later introduction was associated with increased risk for allergy development.

CLINICAL IMPLICATIONS

For infants at low risk for development of food allergies, providers should advise caregivers to introduce potentially allergenic foods with other solid foods between 4 and 6 months of age when children show an interest in eating solids. Infants at high risk for peanut allergy, should be evaluated by an allergy specialist prior to introduction of peanuts and work with providers to create an individualized plan for introduction of peanuts and other allergenic foods as needed.

Diet Quality throughout Early Life in Relation to Allergic Sensitization and Atopic Diseases in Childhood

Early-life nutrition is an important modifiable determinant in the development of a child’s immune system, and may thereby influence the risk of allergic sensitization and atopic diseases. However, associations between overall dietary patterns and atopic diseases in childhood remain unclear. We examined associations of diet quality in early life with allergic sensitization, self-reported physician-diagnosed inhalant and food allergies, eczema, and asthma among 5225 children participating in a population-based cohort in the Netherlands. Diet was assessed during pregnancy, infancy, and childhood using validated food-frequency questionnaires. We calculated food-based diet quality scores (0–10 or 0–15), reflecting adherence to dietary guidelines. At age 10 years, allergic sensitization was assessed with skin prick tests. Information on physician-diagnosed inhalant and food allergies, eczema, and asthma was obtained with questionnaires. We observed no associations between diet quality during pregnancy and allergic sensitization (odds ratio (OR) = 1.05 per point in the diet score, 95% confidence interval (CI): 0.99, 1.13), allergies (0.96, 95% CI: 0.88, 1.04), eczema (0.99, 95% CI: 0.93, 1.06), or asthma (0.93, 95% CI: 0.85, 1.03) in childhood. Also, diet quality in infancy or childhood were not associated with atopic outcomes in childhood. Our findings do not support our hypothesis that a healthy dietary pattern in early life is associated with a lower risk of allergic sensitization or atopic diseases in childhood.

Prevention of allergies in childhood - where are we now?

Allergic diseases represent an increasing health problem for children worldwide. Along with allergic airway diseases, food allergy comes to the fore and herewith closely intertwined the hypothesis that an early allergic sensitization might occur via skin barrier defect(s). The importance of the skin barrier has been documented by several studies meanwhile. Not only genetic studies screen the associations between Filaggrin loss-of-function mutations, atopic dermatitis, allergic sensitization, food allergy and even airway diseases, but also epidemiological studies cast new light on the hypothesis of the atopic march. As another focus in context of the development of an allergic phenotype, the specific microbial exposure with all its diversities has been crystallized as it shapes the immune system in (early) infancy. Studies explored both, the role of human intestinal microbiota as well as the external microbial diversity. Unfortunately suitable markers for atopic predictors are still rare. New studies point out that specific IgE antibodies (e.g., IgE to Phl p 1) in children without allergic symptoms so far, might function as a pre-clinical biomarker, which may help to identify candidates for primary (allergen non-specific) or secondary (allergen-specific) prevention in terms of specific immunoprophylaxis. These manifold research activities document a complex increase in knowledge. Nevertheless new assumptions need to be substantively confirmed in order to finally generate the urgently needed preventive strategies for allergic diseases in childhood.

Gut Microbiota as a Target for Preventive and Therapeutic Intervention against Food Allergy

The gut microbiota plays a pivotal role in immune system development and function. Modification in the gut microbiota composition (dysbiosis) early in life is a critical factor affecting the development of food allergy. Many environmental factors including caesarean delivery, lack of breast milk, drugs, antiseptic agents, and a low-fiber/high-fat diet can induce gut microbiota dysbiosis, and have been associated with the occurrence of food allergy. New technologies and experimental tools have provided information regarding the importance of select bacteria on immune tolerance mechanisms. Short-chain fatty acids are crucial metabolic products of gut microbiota responsible for many protective effects against food allergy. These compounds are involved in epigenetic regulation of the immune system. These evidences provide a foundation for developing innovative strategies to prevent and treat food allergy. Here, we present an overview on the potential role of gut microbiota as the target of intervention against food allergy.

Nutritional aspects of commercially prepared infant foods in developed countries: a narrative review

Nutritional intake during infancy is a critical aspect of child development and health that is of significant public health concern. Although there is extensive research on breast-feeding and timing of solid food introduction, there is less evidence on types of solid foods fed to infants, specifically commercially prepared infant foods. The consumption of commercially prepared infant foods is very prevalent in many developed countries, exceeding the consumption of homemade foods in some situations. Although these food products may have practical advantages, there are concerns about their nutritional composition, sweet taste, bioavailability of micronutrients, diversity of ingredients and long-term health effects. The extent that the manufacturing, fortification and promotion of these products are regulated by legislation varies between countries and regions. The aim of the present narrative review is to investigate, appraise and summarise these aspects. Overall there are very few studies directly comparing homemade and commercial infant foods and a lack of longitudinal studies to draw firm conclusions on whether commercial infant foods are mostly beneficial or unfavourable to infant health.

The Prevalence and Natural History of Food Allergy

Numerous studies have demonstrated that the prevalence of food allergy is increasing. Not only are more children being diagnosed with food allergies, but studies suggest that when people outgrow their food allergies, it is taking longer than was previously thought. Studies in recent years have noted factors that may lead to a lower likelihood of developing a food allergy, including the early introduction of common food allergens, having a sufficient vitamin D level, or having a higher maternal intake of peanut early in pregnancy. Given a recent report that sensitization to common food allergens did not increase from the late 1980s/early 1990s to the mid-2000s, further studies will need to examine if the rise in food allergy prevalence is due to a change in the relationship between sensitization and clinical allergy or changes in the recognition and diagnosis of food allergy.

The aryl hydrocarbon receptor in T cells contributes to sustaining oral tolerance against ovalbumin in a mouse model

Oral tolerance (OT) towards antigens encountered in the gut is a vital immune function of gut immunity. Experimental models can demonstrate OT efficacy by feeding of a protein followed by peripheral immunization and measuring the specific antibody titer. We had previously shown that exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a xenobiotic high-affinity aryl hydrocarbon receptor (AhR)-ligand, destabilized OT against ovalbumin (OVA) in mice. AhR is involved in the development, differentiation and function of immune cells, and highly expressed in gut epithelial cells and gut immune cells. We here used AhR-deficient mice to study the role of AhR in OT further. We show that complete AhR-deficiency undermines the stability of oral tolerance against OVA upon multiple immunizations, despite no renewed oral encounter with the antigen. This OT destabilization is accompanied by significant changes in IL10 and TGFβ RNA in the gut tissue. Using conditional AhR-deficient mouse lines, we identify T cells as the major responsible immune cell type in this context. Our findings add to knowledge that lack of AhR signaling in the gut impairs important gut immune functions.

Modifying the infant's diet to prevent food allergy

Recommendations and guidelines on the prevention of food allergy have changed in recent decades. The aim of this review of the current evidence and ongoing studies is to provide a comprehensive and up to date picture of prevention of food allergy for healthcare professionals. The review was undertaken as part of the European Union funded Integrated Approaches to Food Allergy and Allergen Management (iFAAM) study. This is a wide ranging project bringing together expertise across the breadth of food allergy research. Specifically, the review discusses dietary manipulation in food allergy prevention, and covers the possible preventive strategies of allergen avoidance, early allergen introduction, general nutrition and supplements, as well as other strategies, such as prebiotics and probiotics. The review concludes that despite agreement that allergen avoidance strategies should not be undertaken for allergy prevention, there is currently no consensus regarding what actions should be recommended beyond exclusive breastfeeding for the first 4-6 months of life. Recent and upcoming trial results, which are detailed in this review, should help inform the debate and add clarity to the topic.

Frequency of food group consumption and risk of allergic disease and sensitization in schoolchildren in urban and rural China

BACKGROUND

Diet is a potential determinant of allergic diseases.

OBJECTIVE

To examine in schoolchildren the association between food intake and allergic diseases and determine whether there is effect of environment - rural vs. urban.

METHODS

A questionnaire survey was performed in 11 473 children aged 7-12 years in 20 schools from urban Guangzhou and rural Shaoguan, China. A nested case-control group, 402 from Guangzhou and 349 from Shaoguan, was recruited. Food ingestion frequency data were collected. Serum-specific IgE to 34 food and airborne allergens was determined. Associations between food ingestion frequency and clinical outcomes were sought by logistic analyses.

RESULTS

The prevalence of self-reported asthma (6.6% vs. 2.5%), rhinitis (23.2% vs. 5.3%) and eczema (34.1% vs. 25.9%) was significantly higher in Guangzhou subjects compared to Shaoguan, whereas prevalence of food hypersensitivity (9.7% vs. 9.2%) and food allergy (4.0% vs. 3.5%) was not significantly different. In this case-control study, seafood and fruits were two major food groups causing food hypersensitivity. Urban children consumed more milk, egg, chocolate, fruits, vegetable and cereals compared to rural children. Significantly higher percentage of Guangzhou children was sensitized to egg and milk, whereas more Shaoguan children were sensitized to seafood, nuts and seeds, fruit, vegetables, legumes and cereals. High consumption of milk (OR 2.604, 95 CI% 1.569-4.322, P < 0.001) and vegetables (OR 0.382, 95% CI 0.180-0.809, P = 0.012) were positively and reversely associated with asthma, respectively.

CONCLUSION

Difference in prevalence of asthma but not food allergy was observed. Diets of schoolchildren are affected by disease-related modification and country's urbanization. High vegetable intake and low milk intake might protect against asthma.

Dietary variety and food group consumption in children consuming a cows' milk exclusion diet

BACKGROUND

Dietary variety is defined as the number of different foods or food groups consumed over a given reference period, the consensus being that dietary variety and dietary quality are positively correlated. Recently there has been considerable interest in the association between infant dietary variety and atopic disease.

METHODS

This was a cross-sectional study of 8- to 27-month-old children from the Isle of Wight, UK, including two groups: a group of children consuming a cows' milk exclusion (CME) diet and a control group of children consuming an unrestricted diet. Parents completed a validated food frequency questionnaire, from which dietary variety and consumption of food groups were calculated. Growth measurements were recorded.

RESULTS

A total of 126 participants of mean age 13.0 months were recruited. In addition to the expected differences in dairy and soya consumption, the CME group consumed sweet foods 1.6 times less frequently, non-water drinks seven times less frequently (p < 0.05) and ready-made baby foods 15 times more frequently (p < 0.01) than the control group. Overall dietary variety was significantly lower in the CME group (p < 0.01) as was variety of meat and sweet foods consumed. There was a greater concern with healthy eating in the CME group (p < 0.05).

CONCLUSIONS

Children consuming an exclusion diet for cows' milk allergy have an overall less varied diet, including a less varied consumption of meat and sweet foods. Efforts should be made to ensure exclusion diets are as varied as possible to optimize nutritional intake.

Taste preference, food neophobia and nutritional intake in children consuming a cows' milk exclusion diet: a prospective study

BACKGROUND

Taste exposure in infancy is known to predict food preferences later in childhood. This is particularly relevant in children with cows' milk allergy who consume a substitute formula and/or a cows' milk exclusion (CME) diet early in life. This prospective study aimed to show whether there is a long-term effect of consuming a substitute formula and CME diet on taste preferences and dietary intake.

METHODS

Children were predominantly recruited from two large birth cohort studies in the UK. Two groups were recruited: an experimental group of children who had consumed a CME diet during infancy and a control group who had consumed an unrestricted diet during infancy. Parents completed a food neophobia questionnaire and an estimated prospective food diary. Children completed a taste preference test and their growth was assessed.

RESULTS

One hundred and one children with a mean age of 11.5 years were recruited (28 CME and 73 controls). Children in the CME group had a significantly higher preference for bitter taste than those in the control group (P < 0.05). There were significant differences between the groups with respect to the intake of some micronutrients, including riboflavin, iodine, sodium and selenium. Food neophobia did not differ between groups. Some 28% of the CME group were overweight/obese compared to 15% of the control group; however, this difference was not statistically significant.

CONCLUSIONS

Consuming a substitute formula and/or a CME diet in infancy has a long-term effect on the preference for bitter taste. Differences exist with respect to the intake of some micronutrients, but not macronutrients. There was a nonsignificant trend towards being overweight and obese in children in the CME group.

Nutritional adequacy of a cows' milk exclusion diet in infancy

BACKGROUND

Infants with suspected cows' milk allergy are required to follow a strict milk exclusion diet which may lead to nutritional deficiencies, especially if not supervised by a healthcare professional. The aim of this study was to assess the nutritional adequacy of a cows' milk exclusion diet in a group of UK infants over a period of 6 months.

METHODS

Participants in this study are a subgroup of the Prevalence of Infant Food Allergy study, a prospective food allergy birth cohort study from the South of England. Each infant consuming a milk free diet, following advice from a specialist allergy dietitian, was matched to two control infants who were consuming an unrestricted diet, forming a nested matched case-control study. Detailed food diaries completed prospectively for 1 week per month over a 5 month period, were coded and analysed according to a standard protocol.

RESULTS

The diets of 39 infants (13 milk-free and 26 controls) were assessed. Mean age at diet commencement was 14 weeks. Two of the eleven infants started on an extensively hydrolysed formula did not tolerate it and required an amino acid formula for symptom resolution. All infants had mean intakes in excess of the estimated average requirement for energy and the recommended nutrient intake (RNI) for protein, calcium, iron, selenium, zinc, vitamins A, C and E. Vitamin D intake was in excess of the RNI at all time-points, except at 44 weeks of age. Across the study period, selenium intake was higher for infants consuming a milk free diet whilst vitamin C intake was higher for infants consuming an unrestricted diet. Differences were found between the two groups for protein, calcium, iron and vitamin E intakes at differing time points.

CONCLUSION

This study demonstrated that although infants consuming a milk-free diet have a nutritional intake that is significantly different to matched controls who are eating an unrestricted diet, this difference is not constant and it is not seen for all nutrients. Further research in infants without dietetic input is needed to explore the nutritional implications of unsupervised cows' milk exclusion diets.