Randomized placebo-controlled trial of hen's egg consumption for primary prevention in infants

Emerging concepts in introducing foods for food allergy prevention

PURPOSE OF REVIEW

This review focuses on the latest information regarding the role of complementary feeding practices and food allergen introduction in the prevention of food allergies.

RECENT FINDINGS

Early introduction of food allergens for food allergy prevention is recommended by food allergy prevention guidelines and is supported by the latest randomized controlled trials. Diet diversity is recommended, supported by the latest studies from Asia. A European study indicated that diet diversity after the first year of life may still be important for food allergy prevention. The latest systematic reviews indicate there may be an association between ultra-processed food intake and food allergy development. Plant based foods and fiber play an important role in modulating the gut microbiome which has been associated with reduced food allergy outcomes. However, increased intake of food allergens within a diverse diet raises questions about excessive calorie and protein intake but can be managed by focusing on infant satiety cues.

SUMMARY

The latest studies clearly indicate and further supports that introduction of food allergies should not be delayed once complementary feeding is commenced. A diverse diet is recommended to further support the prevention of food allergies.

Early-Life Allergen Exposure and Its Influence on Risk of Atopic Disease

Childhood allergic diseases and asthma have their origins in early life, and allergen exposures during this period could be a critical determinant of the progression to tolerance versus disease. Mechanisms for sensitization may be different but overlapping for food and aeroallergen sensitization in children. This suggests differences in how exposure to food and aeroallergens influence allergic sensitization. For food allergy, introducing foods such as peanut and egg proteins into the diet at an early age reduces the risk of peanut and egg allergy, respectively, across a broad demographic, whereas evidence is less established for other foods. The relationship between allergen exposure and sensitization to aeroallergens is more complex but critical, given the close relationship between specific immunoglobulin E and respiratory disease. Several factors could mediate the progression from allergen exposure and allergic sensitization versus tolerance, including epithelial barrier function and altered immune development at the skin and mucosal surfaces, exposure to irritants and pollutants, and genetic susceptibility. Collectively, the current evidence base provides a compelling rationale for the primary prevention of food allergy by introducing common allergens such as peanut and egg early. In contrast, primary prevention of aeroallergen sensitization is more complex and perhaps more challenging to achieve by manipulating allergen exposures. Even so, recent advances in understanding how the microbiome and environmental toxins and irritants modulate the mucosal immune response have identified potential new strategies for primary prevention of food and aeroallergen sensitization.

Feeding Practices in the Introduction of Complementary Feeding and Implications for Future Healthy Eating

BACKGROUND

Complementary feeding (CF) is the process of introducing foods that starts when breast milk or formula alone can no longer meet infant's nutritional requirements. Nevertheless, the goal of introducing solid foods is to supplement, not replace, human milk or infant formula. The timing of introduction of CF is a pivotal issue in paediatrics.

SUMMARY

According to the World Health organization (WHO), ideally CF begins at 6 months of age and continues until 23 months, although breastfeeding may extend beyond this period. In low-resource setting areas due to food and water hygiene issues and less availability of complementary foods (CFs) with good nutritional quality, early CF represents a harm. In the meantime, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and European Food Safety Authority (EFSA) recommend that CF should start between 17 and 26 weeks of age. This indication is provided because an early introduction of CFs before 4 months has harming results for both renal and gastrointestinal function and is inadequate with respect to neurodevelopmental skills. The concern about late introduction after 6 months mainly arises from inadequacy of breast milk in providing critical nutrients, particularly iron. Moreover, accumulating evidence suggests a potential higher risk of food allergies (i.e., peanut) when delaying exposure to allergens, rather than preventing their occurrence.

Daily egg intake may reduce sensitisation to common allergenic foods among six- to nine-month-old south African infants: A randomized controlled trial

BACKGROUND

This study aimed to investigate sensitization to eggs and other common allergenic foods, allergic symptoms, and fatty acid status among infants after introducing daily eggs as a complementary food for 6 months.

METHODS

This secondary analysis used data from a randomized controlled trial of 500 infants aged 6-9 months in Jouberton, South Africa, who were randomly assigned to receive one egg daily, n = 250 (treatment) or no egg, n = 250 (control) for 6 months. Clinical allergy symptoms were assessed with the Childhood Allergy and Immunology Research questionnaire. Infants were tested with a skin prick test for egg sensitization at baseline and at the end of the study for additional food allergens. The fatty acid composition was analyzed in whole blood at the endpoint.

RESULTS

At the endpoint, egg sensitization was 1.9% in the egg intervention group and 2.0% in the control group (aOR 0.936 [95% CI 0.229, 3.822]; p = .926) and all foods sensitization was 7.5% in the egg intervention group and 12.9% in the control group (aOR 0.515 [0.264, 1.005]; p = .052). There were no reported acute egg-related allergy symptoms at baseline and midpoint in the two groups. The incidence of allergic disease during the study was 7.5% in the egg intervention group and 13.4% in the control group (aOR = 0.545 [95% CI: 0.283, 1.048]; p = .069). The total and long-chain polyunsaturated fatty acid omega-6/omega-3 ratios were higher in the intervention group (β = .173 [0.291, 2.898], p = .021 and β = .198 [0.149, 0.902], p = .007) with no effect on omega-3 fatty acid composition.

CONCLUSION

Complementary feeding with daily eggs may reduce overall allergic sensitization to common allergenic foods.

The baked side: Cow's milk and egg protein threshold dose distributions in children reacting to baked milk and baked egg

Background

Children allergic to milk and egg, but tolerant to baked products, display higher reactivity thresholds than the general population of children allergic to milk and egg. We sought to verify the reactivity thresholds of milk- and egg-allergic children who also react to baked milk and baked egg, respectively.

Methods

We retrospectively assessed consecutive oral food challenge (OFC) for baked milk and egg between January 2018 and March 2022 in a population of baked milk- and baked-egg allergic children.

Results

Among 407 children included (median age 56 - IQR 31.1-103.7 months, 67.1% male), 93 (23.6%) returned positive OFC results, 41 with baked milk, and 52 with baked egg. The most conservative ED01 was 0.4 mg total protein (IQR 0.1-2.7) for milk and 2.2 mg total protein (IQR 0.6-7.3) for egg. The respective ED05 was 3.9 (IQR 1.1-14) mg for milk and 11.7 (IQR 5-27.2) mg for egg. Such thresholds are consistent to those found for fresh milk (0.8 times for ED01, 1.1 times for ED05). For egg, they are 6.5 (egg ED01), and 7.5 (egg ED05) times lower than for native form.Compared to the currently used thresholds, they are 1.3 (milk ED01), 1.3 (milk ED05), 11 (egg ED01), and 4.9 (egg ED05) times higher.

Conclusions

Milk thresholds are similar to those already observed in baked allergic versus baked tolerant children, while EDs for egg are at least 1.6 times higher than those currently indicated.Egg-allergic patients could be exempt from the recommendations of absolute avoidance of foods when present in infinitesimal quantities, represented by precautionary allergen labelling based on current EDs.

Primary prevention of food allergy: beyond early introduction

Food allergy typically begins early in life and persists as a lifelong condition. Delayed introduction of allergenic foods followed by years of hesitancy to introduce these foods early may have contributed to the increase in food allergy prevalence in recent decades. Most infant feeding guidelines focus on the importance of early introduction of allergenic foods in infants at around age 4-6 months. However, regular, ongoing ingestion of allergenic foods is also critical for the primary prevention of food allergy. Similarly, intermittent exposure to cow's milk formula (CMF) in early infancy increases the risk of cow's milk allergy (CMA), while regular exposure (if it is introduced) prevents it. Families hesitant to introduce allergenic foods to their infant at home (despite education) should be offered introduction in a primary care clinic. Infants who have failed primary prevention should be referred to an allergist for consideration of early infant oral immunotherapy (OIT).

Canadian Society of Allergy and Clinical Immunology position statement: panel testing for food allergies

This position statement addresses the critical concerns and recommended practices surrounding the use of panel food testing for diagnosing food allergies. Food allergies are a significant public health concern, and the misdiagnosis of food allergies remains a prevalent concern, made worse by the ongoing use of panel food testing. The practice of screening patients for multiple food allergens, regardless of clinical relevance, is commonly referred to as "panel food testing." Fundamentally, a panel food test is not simply a single test; a panel food test is a series of several distinct tests for multiple foods, each with its own variable predictive value. These tests have not been adequately validated as screening tests and carry a considerable false positive rate. The resulting false diagnoses lead to unnecessary dietary restrictions, increased healthcare costs, and significant psychosocial distress for patients and their families.

Skin and oral intervention for food allergy prevention based on dual allergen exposure hypothesis

Early-onset atopic dermatitis increases an individual's risk of food allergies, suggesting that transcutaneous sensitization may occur through inflamed skin. Regarding food allergy causation, the dual allergen exposure hypothesis proposes that oral allergen exposure leads to immune tolerance, whereas allergen exposure via inflamed skin causes food allergies. This hypothesis suggests that it is important to induce oral immune tolerance and prevent allergic food sensitization through the skin. This review focuses on the breakthrough evidence based on the dual allergen exposure hypothesis that involves both skin and oral interventions for food allergy prevention.

Immunotherapy and biologics in the management of IgE-mediated food allergy: Systematic review and meta-analyses of efficacy and safety

Food allergy (FA) is a potentially life-threatening chronic condition that is becoming an increasing public health problem worldwide. This systematic review (SR) was carried out to inform the development of clinical recommendations on the treatment of IgE-mediated FA with biologics and/or IT for the update of the EAACI guidelines. A SR of randomized-controlled trials or quasi-controlled trials was carried out. Studies were identified via comprehensive search strategies in Medline, Embase, and Cochrane Library, up to April 2022.

POPULATION

Human adults, children, and adolescents with IgE-mediated FA.

INTERVENTION

IT and/or biologics.

COMPARATOR

Placebo or standard-of-care (allergen avoidance).

OUTCOME

Efficacy (desensitization, sustained unresponsiveness (SU), remission), quality of life, and safety (systemic and local adverse reactions (AR)). The Cochrane RoB tool was used to assess the risk of bias. It was reported according to PRISMA and registered in PROSPERO CRD4202229828. After screening, 121 studies were included (111 for IT and 10 for biologics). Most studies had a high risk of bias and showed high heterogeneity in design and results. Metanalysis showed a positive effect of biologics and IT in terms of relative risk (RR) for achieving tolerance to the culprit food compared to avoidance or placebo. Omalizumab for any FA showed a RR of 2.17 [95% confidence interval: 1.22, 3.85]. For peanut allergy, oral IT (OIT) had a RR of 11.94 [1.76, 80.84] versus avoidance or placebo, sublingual IT (SLIT) had a RR of 3.00 [1.04, 8.66], and epicutaneous IT (EPIT) of 2.16 [1.56, 3.00]. OIT had a RR of 5.88 [2.27, 15.18] for cow's milk allergy, and of 3.43 [2.24, 5.27] for egg allergy. There was insufficient data on SLIT or EPIT for the treatment of egg and milk allergies. Most ARs reported were mild. For OIT the most common AR involved the gastrointestinal system and for EPIT, AR's most commonly affected the skin. There was limited data on severe or life-threatening ARs. There was limited evidence for long term efficacy and quality of life. In conclusion, biologics and IT, alone or in combination, are effective in achieving desensitization while on active treatment but more evidence is needed on long-term tolerance as current evidence is not of high quality. Adverse events while on therapy are generally mild to moderate but a long-term comprehensive safety profile is missing. There is a critical need to optimize and standardize desensitization protocols and outcome measures to facilitate our understanding of the efficacy and safety as well as to allow for comparison between interventions.

Early-life risk factors which govern pro-allergic immunity

Allergic diseases affect up to 40% of the global population with a substantial rise in food allergies, in particular, over the past decades. For the majority of individuals with allergy fundamental programming of a pro-allergic immune system largely occurs in early childhood where it is crucially governed by prenatal genetic and environmental factors, including their interactions. These factors include several genetic aberrations, such as filaggrin loss-of-function mutations, early exposure to respiratory syncytial virus, and various chemicals such as plasticizers, as well as the influence of the gut microbiome and numerous lifestyle circumstances. The effects of such a wide range of factors on allergic responses to an array of potential allergens is complex and the severity of these responses in a clinical setting are subsequently not easy to predict at the present time. However, some parameters which condition a pro-allergic immune response, including severe anaphylaxis, are becoming clearer. This review summarises what we currently know, and don't know, about the factors which influence developing pro-allergic immunity particularly during the early-life perinatal period.

Health Promotion of Early and Sustained Allergenic Food Introduction for the Prevention of Food Allergy

Observational studies and landmark randomized control trials support early and sustained allergenic food introduction in infancy as an effective preventive strategy against food allergy development. Despite a consensus regarding the intended goals of early and sustained allergenic food introduction, there have been myriad policy recommendations among health authorities in how to achieve both individual and population-level health outcomes for food allergy prevention. This clinical management review provides an overview on the data that informs early and sustained allergenic food introduction strategies, suggestions on how to advise allergenic food introduction, principles of prevention programs as they relate to food allergy prevention, and health promotion and systems-level challenges that impede achievement of food allergy prevention goals.

A two-sample Mendelian randomization study of mutual relations of six types of diets in atopic dermatitis

BACKGROUND

In the continuous endeavor to find safe and efficient treatments for Atopic Dermatitis (AD), there remains a considerable focus on dietary adjustments. Nevertheless, the limited availability of research and conflicting findings in the academic literature pose a hurdle in establishing conclusive recommendations.

METHOD

Mendelian randomization (MR) was applied to the most comprehensive genome-wide association studies (GWAS) data on tea intake (447 485), green tea intake (n = 64 949), flavored milk intake (n = 64 941), never eat eggs, dairy, wheat, sugar: Wheat products(n = 461 046), never eat eggs, dairy, wheat, sugar: Sugar or foods/drinks containing sugar (n = 461 046), never eat eggs, dairy, wheat, sugar: I eat all of the above (n = 461 046) and atopic dermatitis (n = 218 467). We used the inverse-variance weighted method (IVW) as the primary method.

RESULTS

The IVW analyses have demonstrated an increased tea intake was genetically associated with a reduced risk of AD (odds ratio [OR]: 0.646, 95% confidence interval [CI]: 0.430-0.968, p = 0.034). Furthermore, green tea intake was significantly negatively associated with AD (IVW OR: 0.986, 95% CI: 0.975-0.998; p = 0.024) in the IVW model. AD risk could be reduced by never eating wheat products (IVW OR: 8.243E-04, 95% CI: 7.223E-06-9.408E-02, p = 0.003). There was no association between never eating eggs, dairy, wheat, sugar: Sugar, or foods/drinks containing sugar, I eat all of the above and AD.

CONCLUSIONS

Our MR study suggests a causal relationship between tea intake, green tea intake, and the avoidance of eating wheat products with atopic dermatitis. Our findings recommend that preventing and managing atopic dermatitis may be achieved by never eating wheat products while increasing tea and green tea intake.

Tolerance induction through early feeding to prevent food allergy in infants and children with sensitization against food allergens (TIFFANI): rationale, study design, and methods of a randomized controlled trial

BACKGROUND

Children with sensitization against foods have to be orally food-challenged before eating these foods for the first time. However, the waiting time for an oral food challenge (OFC) in Germany is about 3-6 months. In contrast, there are hints that an early introduction of allergenic foods might be protective regarding the development of food allergy. The aim of this clinical trial is therefore to investigate, whether an introduction and regular consumption of small amounts of food allergens is safe and will result in an increase of tolerance in children with sensitization against food allergens with unknown clinical relevance.

METHODS

In this randomized, placebo-controlled, double-blind, single-center trial, 138 children (8 months to 4 years of age) sensitized to the target allergen(s) hen's egg, cow's milk, peanuts, and/or hazelnuts with unknown clinical relevance will be randomized in a 1:1 ratio to either an active or a placebo group, daily receiving a rusk-like biscuit powder with or without the target allergen(s) for 3-6 months until an OFC will be performed in routine diagnostics. The primary endpoint is an IgE-mediated food allergy to the primary target allergen, after the interventional period.

DISCUSSION

Children with sensitization against food allergens with unknown clinical relevance often have to avoid the corresponding foods for several months until an OFC is performed. Therefore, the "window of opportunity" for an early preventive introduction of allergenic foods might be missed. This trial will assess whether an introduction of small allergen amounts will favor tolerance development in these children.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00032769. Registered on 02 October 2023.

Introduction of allergenic food to infants and allergic and autoimmune conditions: a systematic review and meta-analysis

OBJECTIVES

To evaluate the effects of early introduction to allergenic foods compared with late introduction and its impact on food allergy, food sensitisation and autoimmune disease risk.

DESIGN AND SETTING

The systematic review was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Four electronic databases (MEDLINE, CENTRAL, EMBASE and CINAHL) were searched from inception till 24 October 2022 using keywords and MeSH without limitations on publication's language or date. A forward and backwards citation analysis was also conducted. Risk of bias was assessed by three authors independently, in pairs using the Cochrane Risk of Bias Tool 2. Findings were narratively and quantitatively synthesised. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

PARTICIPANTS

Randomised controlled trials (RCTs) on allergenic food introduction prior to 12 months of age that evaluated its effect on the development of allergic and autoimmune conditions.

INTERVENTION

Early introduction to allergenic foods to infants diet.

MAIN OUTCOME MEASURES

(1) Food allergy and sensitisation with main measures including oral food challenge, specific-IgE, skin prick testing, physician assessment and parental reporting. (2) Allergic and autoimmune conditions such as asthma and eczema.

RESULTS

Of the 9060 identified records, we included 12 RCTs. We found high to moderate certainty evidence suggested that early introduction of allergen-containing foods reduces the risk of multiple food allergies (4 RCTs, 3854 participants, RR 0.49, 95% CI 0.33 to 0.74), egg (8 RCTs, 5193 participants, RR 0.58, 95% CI 0.44 to 0.78), peanut (3 RCTs, 4183 participants, RR 0.31, 95% CI 0.17 to 0.54) and atopic dermatitis or eczema (4 RCTs, 3579 participants, RR 0.88, 95% CI 0.78 to 1.00). Effects on other food allergies including milk, wheat, fish; autoimmune conditions, and food sensitisation are very uncertain and informed by low and very-low certainty evidence. No important subgroup differences were observed related to baseline risk of allergy and age at introduction. Sensitivity analyses limited to low risk of bias RCTs showed similar results.

CONCLUSIONS

This systematic review and meta-analysis shows that early introduction of allergen-containing food from 4 to 12 months of age, was associated with lower risk of multiple food allergy and eczema. Further research on other allergenic foods, and their long-term impact on food allergy and autoimmune risk is essential for enhancing our understanding on development of these conditions and guiding future clinical recommendations.

PROSPERO REGISTRATION NUMBER

CRD42022375679.

Complementary Feeding: Tradition, Innovation and Pitfalls

According to WHO, "complementary feeding (CF) is the process starting when breast milk alone or infant formula alone is no longer sufficient to meet the nutritional requirements of infants, and therefore, other foods and liquids are needed, along with breast human milk or a breastmilk substitute". CF is one of the most important "critical and sensitive periods" in human life: indeed, timing and approaches to solid foods introduction in an infant's nutrition are of utmost importance as potential epigenetic factors from infancy to adulthood. CF is also deeply influenced by each country and single-family traditions, culture, and beliefs. The aim of our narrative review is to analyze traditional CF practices, including innovative and alternative ones that emerged in the last decades, such as baby-led weaning or plant-based weaning, and to evaluate their effects on the risk of developing non-communicable diseases. Moreover, we will discuss pitfalls and misunderstandings that pediatricians frequently have to face when dealing with complementary feeding. Health care professionals must not have prejudices against parents' wishes or traditions about CF; rather, they should support and educate them in case of any alternative CF choice, always pursuing the infant's adequate growth, neuro- and taste development, and the achievement of correct eating behavior as the primary goal.

Dietary Intervention during Weaning and Development of Food Allergy: What Is the State of the Art?

Food allergy (FA) affects approximately 6-8% of children worldwide causing a significant impact on the quality of life of children and their families. In past years, the possible role of weaning in the development of FA has been studied. According to recent studies, this is still controversial and influenced by several factors, such as the type of food, the age at food introduction and family history. In this narrative review, we aimed to collect the most recent evidence about weaning and its role in FA development, organizing the gathered data based on both the type of study and the food. As shown in most of the studies included in this review, early food introduction did not show a potential protective role against FA development, and we conclude that further evidence is needed from future clinical trials.

Anaphylaxis: A 2023 practice parameter update

This practice parameter update focuses on 7 areas in which there are new evidence and new recommendations. Diagnostic criteria for anaphylaxis have been revised, and patterns of anaphylaxis are defined. Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders. In infants and toddlers, age-specific symptoms may differ from older children and adults, patient age is not correlated with reaction severity, and anaphylaxis is unlikely to be the initial reaction to an allergen on first exposure. Different community settings for anaphylaxis require specific measures for prevention and treatment of anaphylaxis. Optimal prescribing and use of epinephrine autoinjector devices require specific counseling and training of patients and caregivers, including when and how to administer the epinephrine autoinjector and whether and when to call 911. If epinephrine is used promptly, immediate activation of emergency medical services may not be required if the patient experiences a prompt, complete, and durable response. For most medical indications, the risk of stopping or changing beta-blocker or angiotensin-converting enzyme inhibitor medication may exceed the risk of more severe anaphylaxis if the medication is continued, especially in patients with insect sting anaphylaxis. Evaluation for mastocytosis, including a bone marrow biopsy, should be considered for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis. After perioperative anaphylaxis, repeat anesthesia may proceed in the context of shared decision-making and based on the history and results of diagnostic evaluation with skin tests or in vitro tests when available, and supervised challenge when necessary.

Complementary Feeding Practices: Recommendations of Pediatricians for Infants with and without Allergy Risk

AIM

To investigate the routine guidance provided by pediatricians concerning the timing of complementary feeding (CF) for both healthy infants and those at a heightened risk of allergies.

METHODS

A total of 233 pediatricians participated in an anonymous online survey that included questions about demographics and recommendations for CF. Specifically, they provided guidance on the types of foods, preparation methods, supplements, time intervals for introducing new foods to infants at low and high allergy risk, and delayed food introductions for high-risk cases.

RESULTS

The respondents advised introducing certain foods at specific ages: fruits, starchy non-gluten grains, vegetables, olive oil, and meat were appropriate at 6 months; gluten-rich grains at 7 months; yogurt, hard-boiled eggs, and legumes at 8 months; fish at 8.5 months; and nuts at 9 months. Pediatricians, especially those with less than 15 years of practice, often introduced egg, seafood, gluten-rich grains, legumes, and nuts earlier for high-risk infants. Parenthood and male gender were associated with the earlier introduction of eggs and grains.

CONCLUSIONS

Greek pediatricians follow a structured food introduction schedule for CF in infants. Interestingly, they tend to delay the introduction of common food allergens and recommend longer intervals between introducing new foods, particularly for high-risk infants. Key Notes: Despite recent evidence-based indications on healthy complementary feeding strategies for infants, discrepancies persist among pediatricians regarding food choices and the order and timing of food introduction, both for healthy infants and those at risk of allergy. Guidance on complementary feeding by pediatricians is influenced by their individual characteristics. Pediatricians tend to delay the introduction of common food allergens and recommend longer intervals between introducing new foods, particularly for high-risk infants.

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.

Tolerance to heated egg in egg allergy: Explanations and implications for prevention and treatment

Hen's egg allergy is the second most frequent food allergy found in children. Allergic symptoms can be caused by raw or heated egg, but a majority of egg-allergic children can tolerate hard-boiled or baked egg. Understanding the reasons for the tolerance towards heated egg provides clues about the molecular mechanisms involved in egg allergy, and the differential allergenicity of heated and baked egg might be exploited to prevent or treat egg allergy. In this review, we therefore discuss (i) why some patients are able to tolerate heated egg; by highlighting the structural changes of egg white (EW) proteins upon heating and their impact on immunoreactivity, as well as patient characteristics, and (ii) to what extent heated or baked EW might be useful for primary prevention strategies or oral immunotherapy. We describe that the level of immunoreactivity towards EW helps to discriminate patients tolerant or reactive to heated or baked egg. Furthermore, the use of heated or baked egg seems effective in primary prevention strategies and might limit adverse reactions. Oral immunotherapy is a promising treatment strategy, but it can sometimes cause significant adverse events. The use of heated or baked egg might limit these, but current literature is insufficient to conclude about its efficacy.

Timing of complementary feeding for early childhood allergy prevention: An overview of systematic reviews

OBJECTIVE

To summarise and critically appraise systematic review (SR) evidence on the effects of timing of complementary feeding (CF) on the occurrence of allergic sensitisation and disease.

DESIGN

Overview of SRs. AMSTAR-2 and ROBIS were used to assess methodological quality and risk of bias (RoB) of SRs. RoB 2 Tool was used to assess RoB of primary randomised controlled trials (RCTs) (or extracted). The certainty of evidence (CoE) was assessed using GRADE. Findings were synthesised narratively.

DATA SOURCES

MEDLINE (via PubMed and Ovid), the Cochrane Library and Web of Science Core Collection (2010 to 27 February 2023).

ELIGIBILITY CRITERIA

SRs investigating the effects of timing of CF in infants or young children (0-3 years) on risk of developing food allergy (FA), allergic sensitisation, asthma, allergic rhinitis, atopic eczema and adverse events based on RCT evidence.

RESULTS

Eleven SRs were included. Only two SRs had low RoB; common issues were failure to report on funding of primary studies and failure to provide a list of excluded trials. Common limitations of included trials were lack of blinding of outcome assessment or detailed trial preregistration, and inadequate handling of high loss to follow up. Primary study overlap was very high for specific FA and slight to moderate for FA in general and other primary outcomes. Introducing specific foods (peanut, cooked egg) early probably reduces the risk of specific FA. Evidence for other allergic outcomes was mostly very uncertain and based on few primary studies. Trials varied regarding timing of CF, nature of complementary foods and population risk, which limited comparability between SRs.

CONCLUSIONS

For developing guidelines to support decision-making on the timing of CF as a preventive strategy, early introduction of specific foods (i.e. egg and peanut) seems promising and safe, whereas more extensive research is required regarding other allergic outcomes and potential adverse events.

Development of peanut, sesame and tree nut allergy in Polish children at high risk of food allergy: a protocol for a cross-sectional study

INTRODUCTION

Peanut allergies cause serious health problems worldwide. A strong finding has shown that the early introduction of peanuts into the diet of infants at high risk of food allergy reduces the prevalence of peanut allergy. Allergies to peanuts, sesame and tree nuts have been shown to coexist in 60% of cases and vary according to geographical location and dietary habits. Insights into the prevalence of nut and seed allergies in societies with varying consumption levels are essential for developing population-specific weaning guidelines. Understanding the age at which peanut allergy develops is paramount for successful early introduction strategies.

METHODS AND ANALYSIS

We will perform a cross-sectional study at two tertiary allergy centres in Warsaw and Bydgoszcz. Two hundred forty children aged 4-36 months with eczema or egg allergy will undergo an extensive assessment of their peanut, sesame and tree nut allergy status through skin testing, specific IgE measurements and oral food challenges. The primary outcome is the prevalence of peanut, sesame and tree nut allergies in Polish children at high risk of food allergy. Additionally, the timing of the development of peanut, sesame and tree nut allergies in the first 3 years of life in a high-risk population will be assessed.

ETHICS AND DISSEMINATION

The Ethics Committee of the Medical University of Warsaw, Poland approved this protocol (KB/86/2021). The results of this study will be submitted to a peer-reviewed journal no later than 1 year after data collection. The abstract will be presented at relevant national and international conferences.Although the authors may be able to commit to journal submission no later than 1 year after data collection, publication dates remain beyond their control.

TRIAL REGISTRATION NUMBER

NCT05662800.

Updates in Food Allergy Prevention in Children

Although significant evidence exists that feeding early has a role in the prevention of food allergy, this intervention in isolation may not be sufficient. Recent evidence highlights that early introduction of peanut specifically has had no significant impact on the populational prevalence of peanut allergy. Other factors that may contribute to food allergy prevention include regularity of ingestion once an allergen is introduced and consideration to the form in which the allergen is introduced (such as baked versus cooked egg). There are also many practicalities to early feeding and some discrepant viewpoints on these practicalities, which has led to poor implementation of early feeding strategies. In general, preemptive screening before food introduction is not recommended by most international allergy societies. Although there is little guidance to inform early introduction of allergens other than milk, egg, and peanut, the mechanism of sensitization is thought to be similar and there is no harm to early introduction. In terms of frequency and duration of feeding, there is little evidence to inform any concrete recommendations.

Early-life risk factors for food allergy: Dietary and environmental factors revisited

There appears a steep increase in the prevalence of food allergy worldwide in the past few decades. It is believed that, rather than genetic factors, the recently altered dietary and environmental factors are the driving forces behind the rapid increase of this disease. Accumulating evidence has implied that external exposures that occurred in prenatal and postnatal periods could affect the development of oral tolerance in later life. Understanding the potential risk factors for food allergy would greatly benefit the progress of intervention and therapy. In this review, we present updated knowledge on the dietary and environmental risk factors in early life that have been shown to impact the development of food allergy. These predominantly include dietary habits, microbial exposures, allergen exposure routes, environmental pollutants, and so on. The key evidence, conflicts, and potential research topics of each theory are discussed, and associated interventional strategies to prevent the disease development and ameliorate treatment burden are included. Accumulating evidence has supported the causative role of certain dietary and environmental factors in the establishment of oral tolerance in early life, especially the time of introducing allergenic foods, skin barrier function, and microbial exposures. In addition to certain immunomodulatory factors, increasing interest is raised toward modern dietary patterns, where adequately powered studies are required to identify contributions of those modifiable risk factors. This review broadens our understanding of the connections between diet, environment, and early-life immunity, thus benefiting the progress of intervention and therapy of food allergy.

Early Introduction of Novel and Less-Studied Food Allergens in the Plant-Based Era: Considerations for US and EU Infant Formula Regulations

Early life feeding practices may affect the long-term health of individuals, particularly in terms of the development of non-communicable diseases, such as metabolic and allergic diseases. Accumulating evidence suggests that the interplay of breastfeeding and/or formula feeding followed by the introduction of solids plays a role in the occurrence of non-communicable diseases both in the short and long term. International food allergy guidelines recommend that breastfeeding women do not need to avoid food allergens and do not recommend any infant formula for allergy prevention. Guidelines regarding solid food introduction for food allergy prevention recommend the introduction of well-cooked eggs and peanuts around 4-6 months of age, and not to delay the introduction of other food allergens. There is also an increasing trend to feed infants a plant-based or plant-forward diet and have access to infant formulas based on plant-based ingredients. The use of novel plant-based infant formulas raises a few questions reviewed in this paper: (1) Do fortified, plant-based infant formulas, compliant with US Food and Drug Administration (FDA) regulations and European Food Safety Authority (EFSA) (European) guidelines, support adequate infant growth? (2) Are plant-based infant formulas suitable for the management of cow's milk allergy? (3) Does feeding with novel, plant-based infant formulas increase the risk of food allergies to the food allergens they contain? (4) Does feeding infants plant-based food allergens in early life increase the risk of allergic and severe allergic reactions? The review of the literature indicated that (1) plant-based formulas supplemented with amino acids and micronutrients to comply with FDA regulations and EFSA guidelines, evaluated in sufficiently powered growth studies, can support adequate growth in infants; (2) currently available plant-based infant formulas are suitable for the management of CMA; (3) an early introduction and continuous intake of food allergens are more likely to prevent food allergies than to increase their risk; and (4) an early introduction of food allergens in young infants is safe.

Spanish Pediatricians' Positions Regarding Prevention, Diagnosis, Nutritional Management, and Challenges in Cow's Milk Protein Allergy

Management of cow's milk protein allergy (CMPA) can vary depending on the experience and area of expertise of the clinician responsible for the patient's follow-up, which may or may not align with the recently published literature. To analyze the perspectives of Spanish pediatricians on this topic, a survey was conducted. The survey aimed to determine the current opinions and attitudes of 222 primary care and hospital pediatricians toward CMPA prevention and nutritional management. Participating pediatricians completed the questionnaire, providing insights into their daily clinical practices, including access to testing, attitudes with respect to various aspects of CMPA diagnosis, prevention, oral food challenges, and treatment. The findings revealed that pediatricians generally agree on the use of extensively hydrolyzed formulas (eHFs) to prevent CMPA in high-risk atopic children, despite limited evidence supporting the widespread use of this practice. However, consensus was lacking regarding the utility of formulas with prebiotics and probiotics for expediting tolerance development. In most cases, pediatricians preferred eHFs for the nutritional management of CMPA, followed by hydrolyzed rice formulas (HRFs), with amino-acid-based formulas (AAFs) being the third option. Certain issues remained controversial among pediatricians, such as prevention methods, symptom assessment, and the role of probiotics. These variations in management approaches reflect the influence of clinician experience and area of expertise, underscoring the need for standardized guidelines in this field.

The SunBEAm birth cohort: Protocol design

Background

Food allergy (FA) and atopic dermatitis (AD) are common conditions that often present in the first year of life. Identification of underlying mechanisms and environmental determinants of FA and AD is essential to develop and implement effective prevention and treatment strategies. Objectives: We sought to describe the design of the Systems Biology of Early Atopy (SunBEAm) birth cohort.

Methods

Funded by the National Institute of Allergy and Infectious Diseases (NIAID) and administered through the Consortium for Food Allergy Research (CoFAR), SunBEAm is a US population-based, multicenter birth cohort that enrolls pregnant mothers, fathers, and their newborns and follows them to 3 years. Questionnaire and biosampling strategies were developed to apply a systems biology approach to identify environmental, immunologic, and multiomic determinants of AD, FA, and other allergic outcomes.

Results

Enrollment is currently underway. On the basis of an estimated FA prevalence of 6%, the enrollment goal is 2500 infants. AD is defined on the basis of questionnaire and assessment, and FA is defined by an algorithm combining history and testing. Although any FA will be recorded, we focus on the diagnosis of egg, milk, and peanut at 5 months, adding wheat, soy, cashew, hazelnut, walnut, codfish, shrimp, and sesame starting at 12 months. Sampling includes blood, hair, stool, dust, water, tape strips, skin swabs, nasal secretions, nasal swabs, saliva, urine, functional aspects of the skin, and maternal breast milk and vaginal swabs.

Conclusions

The SunBEAm birth cohort will provide a rich repository of data and specimens to interrogate mechanisms and determinants of early allergic outcomes, with an emphasis on FA, AD, and systems biology.

Infant egg consumption during introduction to solid food remains low in the United Kingdom but increases with infant age and a baby-led weaning approach

BACKGROUND

As a nutritious food-providing protein, essential fatty acids, vitamin D, iodine and choline eggs have historically been central to an infant weaning diet. However, food poisoning scares and allergy concerns have contributed to low consumption among infants aged 6-12 months.

METHODS

This paper presents a secondary data analysis of infant egg exposure and intake using three weaning data sets: a 7-day food frequency questionnaire (n = 297), a 24-h recall (n = 180) and a 3-day weighed food diary (n = 71). Egg introduction, frequency of consumption and intake in grams were analysed for infants aged 6-8, 9-10 and 11-12 months). Comparisons were made by whether infants were following a baby-led approach to weaning (where infants self-feed family foods) or a traditional approach where pureed foods are given alongside finger foods. Data were collected in the United Kingdom between 2015 and 2018.

RESULTS

Our data showed that despite introduction being recommended from the start of weaning at 6 months of age by the Department of Health, just 54% of infants aged 6-8 months had ever been offered eggs. Average egg intake was one to two times per week, increasing with age. However, in terms of frequency and grams consumed, our data suggest a small increase in consumption compared with previous research, although limitations of our smaller sample size should be noted. Finally, a baby-led approach was associated with increased exposure and consumption; baby-led infants consumed eggs twice as frequently as spoon-fed infants.

CONCLUSIONS

The findings have important implications for public health messaging and for supporting families in introducing solid foods.

Timing of Allergenic Food Introduction and Risk of Immunoglobulin E-Mediated Food Allergy: A Systematic Review and Meta-analysis

Importance

Earlier egg and peanut introduction probably reduces risk of egg and peanut allergy, respectively, but it is uncertain whether food allergy as a whole can be prevented using earlier allergenic food introduction.

Objective

To investigate associations between timing of allergenic food introduction to the infant diet and risk of food allergy.

Data Sources

In this systematic review and meta-analysis, Medline, Embase, and CENTRAL databases were searched for articles from database inception to December 29, 2022. Search terms included infant, randomized controlled trial, and terms for common allergenic foods and allergic outcomes.

Study Selection

Randomized clinical trials evaluating age at allergenic food introduction (milk, egg, fish, shellfish, tree nuts, wheat, peanuts, and soya) during infancy and immunoglobulin E (IgE)-mediated food allergy from 1 to 5 years of age were included. Screening was conducted independently by multiple authors.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline was used. Data were extracted in duplicate and synthesized using a random-effects model. The Grading of Recommendations, Assessment, Development, and Evaluation framework was used to assess certainty of evidence.

Main Outcomes and Measures

Primary outcomes were risk of IgE-mediated allergy to any food from 1 to 5 years of age and withdrawal from the intervention. Secondary outcomes included allergy to specific foods.

Results

Of 9283 titles screened, data were extracted from 23 eligible trials (56 articles, 13 794 randomized participants). There was moderate-certainty evidence from 4 trials (3295 participants) that introduction of multiple allergenic foods from 2 to 12 months of age (median age, 3-4 months) was associated with reduced risk of food allergy (risk ratio [RR], 0.49; 95% CI, 0.33-0.74; I2 = 49%). Absolute risk difference for a population with 5% incidence of food allergy was -26 cases (95% CI, -34 to -13 cases) per 1000 population. There was moderate-certainty evidence from 5 trials (4703 participants) that introduction of multiple allergenic foods from 2 to 12 months of age was associated with increased withdrawal from the intervention (RR, 2.29; 95% CI, 1.45-3.63; I2 = 89%). Absolute risk difference for a population with 20% withdrawal from the intervention was 258 cases (95% CI, 90-526 cases) per 1000 population. There was high-certainty evidence from 9 trials (4811 participants) that introduction of egg from 3 to 6 months of age was associated with reduced risk of egg allergy (RR, 0.60; 95% CI, 0.46-0.77; I2 = 0%) and high-certainty evidence from 4 trials (3796 participants) that introduction of peanut from 3 to 10 months of age was associated with reduced risk of peanut allergy (RR, 0.31; 95% CI, 0.19-0.51; I2 = 21%). Evidence for timing of introduction of cow's milk and risk of cow's milk allergy was very low certainty.

Conclusions and Relevance

In this systematic review and meta-analysis, earlier introduction of multiple allergenic foods in the first year of life was associated with lower risk of developing food allergy but a high rate of withdrawal from the intervention. Further work is needed to develop allergenic food interventions that are safe and acceptable for infants and their families.

[Early introduction of potentially allergenic foods in pediatric patients under six months of age]

OBJECTIVE

To review the available evidence on the early introduction of allergenic foods and the possible protection in the development of food allergy in later stages.

METHODS

An exploratory review of randomized clinical trials whose study population included infants less than 6 months of age at enrollment with or without a diagnosis of food allergy was conducted. For the purposes of this review, eggs, peanuts, and wheat were included as potentially allergenic foods. The following databases were consulted: Medline, EBSCO, OVID, Science Direct and JSTOR (Journal Storage), Scielo, LILACS, Redalyc and Imbiomed from August to December 2021.

RESULTS

429 articles were identified, 412 were excluded, and the final analysis included 9 studies that met the inclusion criteria. Six trials correspond to allergy to eggs, two to peanuts and one to wheat. The age of introduction differs in all trials. The earliest exposure was at 3.5 months and the latest at 5.5 months. The reduction in the risk of developing food allergy occurred in children at risk of allergy. Adverse reactions were common, particularly with the introduction of egg.

CONCLUSIONS

We found no evidence that early introduction (< 6 months of age) of allergenic foods reduces the risk of developing food allergy in infants without risk factors.

Quality of systematic reviews on timing of complementary feeding for early childhood allergy prevention

BACKGROUND

Only rigorously prepared analyses can provide the highest level of evidence to inform decision-making. Several recent systematic reviews (SRs) examined the hypothesis that the early introduction of specific allergenic complementary foods (CFs) to infants may lead to a lower incidence of one or more allergic outcomes. However, the methodological rigour and quality of reporting of SRs in this area has not yet been systematically evaluated.

METHODS

We comprehensively searched PubMed, Medline (Ovid), and Web of Science Core Collection on 13th January 2022, using a pre-specified and tested search syntax for SRs with RCT evidence on the early introduction of allergenic CFs as a means for allergy prevention in infants and children. We examined the quality and risk of bias (RoB) using AMSTAR-2 and ROBIS tools, examined adherence to the Preferred Reporting Items for SRs and Meta-Analyses (PRISMA), and checked whether certainty of the evidence was assessed.

RESULTS

Twelve SRs were included. Application of both tools resulted in similar overall judgements in terms of direction and extent for nine of the 12 SRs. Nine SRs were found to be of critically low to low quality according to AMSTAR-2 and to be at high RoB according to ROBIS. One SR received a moderate quality rating (AMSTAR-2) and high RoB rating (ROBIS). However, for two SRs, judgements between AMSTAR-2 and ROBIS were at stark variance. Only two SRs fully adhered to the PRISMA checklist. Six SRs evaluated the certainty of the body of RCT evidence. Several SRs failed to consider unpublished studies either by an explicit a priori exclusion or by inadequate search strategies.

CONCLUSIONS

Well-conducted SRs are important for decision-making and informing guideline development, the quality of their methodology should therefore be considered. The methodological rigour and the reporting quality of SRs on the timing of CF for allergy prevention must be improved.

REGISTRATION

https://osf.io/7cs4b .

A systematic review of quality and consistency of clinical practice guidelines on the primary prevention of food allergy and atopic dermatitis

Background and aims

With an increasing number of Clinical Practice Guidelines (CPGs) addressing primary prevention of food allergy and atopic dermatitis, it is timely to undertake a comprehensive assessment of the quality and consistency of recommendations and evaluation of their implementability in different geographical settings.

Methods

We systematically reviewed CPGs from 8 international databases and extensive website searches. Seven reviewers screened records in any language and then used the AGREE II and AGREE REX instruments to critically appraise CPGs published between January 2011 and April 2022.

Results

Our search identified 2138 relevant articles, of which 30 CPGs were eventually included. Eight (27%) CPGs were shortlisted based on our predefined quality criteria of achieving scores >70% in the "Scope and Purpose" and "Rigour of Development" domains of the AGREE II instrument. Among the shortlisted CPGs, scores on the "Applicability" domain were generally low, and only 3 CPGs rated highly in the "Implementability" domain of AGREE-REX, suggesting that the majority of CPGs fared poorly on global applicability. Recommendations on maternal diet and complementary feeding in infants were mostly consistent, but recommendations on use of hydrolysed formula and supplements varied considerably.

Conclusion

The overall quality of a CPG for Food Allergy and Atopic Dermatitis prevention did not correlate well with its global applicability. It is imperative that CPG developers consider stakeholders' preferences, local applicability, and adapt existing recommendations to each individual population and healthcare system to ensure successful implementation. There is a need for development of high-quality CPGs for allergy prevention outside of North America and Europe.

PROSPERO registration number

CRD42021265689.

Food allergy prevention: Where are we in 2023?

Food allergy prevention involves recommendations to the maternal diet during pregnancy and breast feeding, early life feeding and introduction of solid foods. Pregnant and breastfeeding women are not recommended to exclude any food allergens from their diet, but data are lacking to support active consumption of food allergens for prevention of food allergy. Breastfeeding is recommended for the many health benefits to the mother and child but has not shown any association with reduction in childhood food allergies. There is currently no recommendation regarding the use of any infant formula for allergy prevention, including the use of partially or extensively hydrolyzed formulas. Once the introduction of solid food commences, based on randomized controlled trials, it is advised to actively introduce peanuts and egg early into the infant diet and continue with consumption of these. Although there are limited data with respect to other major food allergens and whether early introduction may prevent allergy development, there is no need to delay the introduction of these allergens into the infant diet. Interpreting food allergen consumption in the context of cultural food practices has not been studied, but it makes sense to introduce the infant to family foods by 1 year of age. Consumption of foods typical of the Western diet and foods high in advanced glycation end products may be associated with an increase in food allergies. Similarly, intake of micronutrients, such as vitamin D and omega-3 fatty acids in both the maternal and infant diet, needs further clarification in the context of food allergy prevention.

Epicutaneous Sensitization and Food Allergy: Preventive Strategies Targeting Skin Barrier Repair-Facts and Challenges

Food allergy represents a growing public health and socio-economic problem with an increasing prevalence over the last two decades. Despite its substantial impact on the quality of life, current treatment options for food allergy are limited to strict allergen avoidance and emergency management, creating an urgent need for effective preventive strategies. Advances in the understanding of the food allergy pathogenesis allow to develop more precise approaches targeting specific pathophysiological pathways. Recently, the skin has become an important target for food allergy prevention strategies, as it has been hypothesized that allergen exposure through the impaired skin barrier might induce an immune response resulting in subsequent development of food allergy. This review aims to discuss current evidence supporting this complex interplay between the skin barrier dysfunction and food allergy by highlighting the crucial role of epicutaneous sensitization in the causality pathway leading to food allergen sensitization and progression to clinical food allergy. We also summarize recently studied prophylactic and therapeutic interventions targeting the skin barrier repair as an emerging food allergy prevention strategy and discuss current evidence controversies and future challenges. Further studies are needed before these promising strategies can be routinely implemented as prevention advice for the general population.

Early, continuing exposure to cow's milk formula and cow's milk allergy: The COMEET study, a single center, prospective interventional study

BACKGROUND

Cow's milk allergy (CMA) is a common food allergy among infants. Information regarding the best timing for first exposure to cow's milk formula (CMF) is controversial and more evidence is required. Few randomized control trials have tried to accurately assess the timing and preventive effect of exposure to CMF on small cohorts.

OBJECTIVE

This study assessed the association between early, continuing exposure to CMF on the basis of the parents' preferences and the development of immunoglobulin E (IgE)-mediated CMA in a large birth cohort.

METHODS

Newborns were prospectively recruited shortly before birth and divided into 2 groups according to parental feeding preference for the first 2 months of life: (1) exclusive breastfeeding (EBF); or (2) at least 1 meal of CMF (with or without breastfeeding) daily. Infants were followed up monthly until the age of 12 months.

RESULTS

Among 1992 infants participating in the study, 1073 (53.86%) were in the EBF group until 2 months of age. IgE-mediated CMA was confirmed in 0.85% (n = 17); all were in the EBF group. Within this group, the prevalence of IgE-mediated CMA was 1.58% compared with 0 in the other groups (relative risk, 29.98; P < .001). Post hoc analysis revealed IgE-mediated CMA prevalence of 0.7% in the per-protocol EBF group vs 3.27% among breastfed infants who were exposed to a small amount of CMF during the first 2 months of life. A family atopic background did not affect the results.

CONCLUSION

Early, continuing exposure to CMF from birth has the potential to prevent the development of IgE-mediated CMA and should be encouraged. However, the exposure needs to be consistent because occasional exposure increases the risk of developing IgE-mediated CMA and should be avoided.

The clinical and immunological basis of early food introduction in food allergy prevention

IgE-mediated food allergy has an estimated prevalence of 6%-10% in developed countries. Allergen avoidance has long been the main focus in the prevention of food allergy and late solid food introduction after 6-12 months of age was recommended in high-risk infants. However, the rising prevalence of food allergy despite delayed exposure to allergens and the observations that IgE-mediated sensitization to food products could even occur before the introduction of solid foods resulted in a shift towards early solid food introduction as an attempt to prevent IgE-mediated food allergy. Since then, many trials focused on the clinical outcome of early allergen introduction and overall seem to point to a protective effect on the development of IgE-mediated food allergies. For non-IgE-mediated diseases of food allergy, evidence of early food introduction seems less clear. Moreover, data on the underlying immunological processes in early food introduction is lacking. The goal of this review is to summarize the available data of immunological changes in early food introduction to prevent IgE and non-IgE mediated food allergy.

Frequency of Infant Egg Consumption and Risk of Maternal-Reported Egg Allergy at 6 Years

BACKGROUND

Recent research suggests that early egg introduction during infancy may help to prevent egg allergy development. However, the infant egg consumption frequency that is sufficient to induce this immune tolerance remains uncertain.

OBJECTIVES

We examined the associations between the infant egg consumption frequency and maternal-reported child egg allergy at 6 y.

METHODS

We analyzed data of 1252 children from the Infant Feeding Practices Study II (2005-2012). Mothers reported the frequency of infant egg consumption at 2, 3, 4, 5, 6, 7, 9, 10, and 12 mo old. Mothers reported the status of their child's egg allergy at the 6-y follow-up. We used Fisher exact test, Cochran-Armitage Trend Test, and log Poisson regression models to compare 6-y egg allergy risk by the frequency of infant egg consumption.

RESULTS

The risk of maternal-reported egg allergy at 6 y significantly (P-trend = 0.004) decreased with infant egg consumption frequency at 12 mo: 2.05% (11/537) for infants not consuming eggs, 0.41% (1/244) for those consuming eggs <2 times per wk, and 0.21% (1/471) for those consuming eggs ≥2 times per wk. A similar but nonsignificant trend (P-trend=0.109) was observed for egg consumption at 10 mo (1.25%, 0.85%, and 0%, respectively). After adjusting for socioeconomic confounders, breastfeeding, complementary food introduction, and infant eczema, infants who consumed eggs ≥2 times per wk at 12 mo had a significantly lower RR of maternal-reported egg allergy at 6 y (confounder-adjusted RR: 0.11; 95% CI: 0.01, 0.88; P = 0.038), whereas those who consumed <2 times per wk (confounder-adjusted RR: 0.21; 95% CI: 0.03, 1.67; P = 0.141) did not have a significantly lower risk than those who did not consume eggs at all.

CONCLUSIONS

Consumption of eggs ≥2 times per wk in late infancy is associated with a reduced risk of developing egg allergy later in childhood.

Prevalence of and risk factors for nutritional deficiency and food allergy in a cohort of 21 patients with Netherton syndrome

BACKGROUND

Netherton syndrome (NS; OMIM: 256500) is a rare autosomal recessively inherited disease due to SPINK5 mutations. Hair and inflammatory skin involvement are variable along with allergies. Morbidity and mortality are high, particularly in infancy. A detailed clinical analysis of a NS patient cohort should broaden the understanding of nutritional challenges and allergic comorbidities.

METHODS

In this retrospective monocentric cohort study, medical and dietetic records of pediatric NS patients, presenting between 1999 and 2018, were reviewed. The severity of skin involvement was assessed according to the extent of the body surface area (BSA) affected by erythema.

RESULTS

We identified 21 patients with NS (median age 11.6 years). Within the first 6 months of life, requirements for fluid and kcals/protein were high for all patients (average 228 ml/kg/day) and infants had an average of 1.9 feed changes (range 0-4) due to food intolerance. Clinical evidence for IgE-mediated food allergy was present in 84.2% (16/19 children, 2 no data) with a range of 1-12 food allergies per patient. In 75%, more than one food had to be avoided. Specific IgE levels were falsely positive in 38.3% and 8/18 patients (44.4%). One-third (5/15; 6 no data) of patients, all with severe disease, had anaphylactic reactions following ingestion of fish (n = 2), sesame (n = 1), cow's milk (n = 1), and both peanut and egg (n = 1).

CONCLUSIONS

Our data emphasize feeding difficulties in children with NS and reveal an unexpectedly higher prevalence of food allergies that gives evidence to the importance of early coordinated multidisciplinary care for overcoming these challenges in NS.

Nutritional Management of Children with Food Allergies

Purpose of the Review

The purpose of the review is to review the evidence for the nutritional management of paediatric food allergy and provide a practical approach for healthcare professionals working in this area.

Recent Findings

Dietary elimination remains the mainstay for management of food allergies in children. However, the elimination of food allergens increases the risk for growth faltering, micronutrient deficiencies and feeding difficulties. Breastmilk remains the ideal source of nutrition for infants, but when not available, the vast majority will tolerate an extensively hydrolysed formula, and rice hydrolysate has also been suggested as a suitable alternative. Only in severe cases, including anaphylaxis, eosinophilic oesophagitis and growth faltering, is an amino acid formula indicated. The early introduction of peanut and egg and avoiding the delay in the introduction of other allergens, when not already allergic, has been highlighted by recent studies.

Summary

Whilst the elimination of allergens increases the risk of developing poor growth, micronutrient deficiencies and feeding difficulties, optimal, early dietary input, including advice on active introduction of allergens and alternative feeds, ideally from a registered dietitian/nutritionist, may be prevent and improve outcomes.

How a Family History of Allergic Diseases Influences Food Allergy in Children: The Japan Environment and Children's Study

The influence of family allergic history on food allergy in offspring in Japan is unknown. We analyzed data from a nationwide birth cohort study using logistic regression models to examine the associations of maternal, paternal, and both parental histories of allergic diseases (food allergy, atopic dermatitis, asthma, and rhinitis) with their child’s food allergy at 1.5 and 3 years of age. This analysis included 69,379 singleton full-term mothers and 37,179 fathers and their children. All parental histories of allergic diseases showed significant positive associations with their child’s food allergy. When both parents had a history of allergic diseases, the adjusted odds ratio (aOR) tended to be higher than when either parent had allergic diseases (p for trend < 0.0001). The highest aOR was detected when both parents had food allergy (2.60; 95% confidential interval, 1.58−4.27), and the aOR was 1.71 when either parent had food allergy (95% confidential interval, 1.54−1.91). The aORs were attenuated but still had significant positive associations after adjusting for the child’s atopic dermatitis, a risk factor for allergy development. In conclusion, all parental allergic diseases were significantly positively associated with their child’s food allergy. The effect of family history showed a stepwise increase in risk from either parent to both parents, and the highest risk of allergic disease was a parental history of food allergy.

Cow's milk and egg protein threshold dose distributions in children tolerant to beef, baked milk, and baked egg

BACKGROUND

The use of eliciting doses (EDs) for food allergens is necessary to inform individual dietary advice and food allergen risk-management. The Eliciting Dose 01 (ED01) for milk and egg, calculated from populations of allergic subjects undergoing oral food challenges (OFCs), are 0.2 mg total protein. The respective Eliciting Dose 05 (ED05) is 2.4 mg for milk and 2.3 mg for egg. As about 70% children allergic to such foods may tolerate them when baked, we sought to verify the EDs of that subpopulation of milk and egg-allergic children.

METHODS

We retrospectively assessed consecutive OFC for fresh milk and egg between January 2018 and December 2020 in a population of baked food-tolerant children.

RESULTS

Among 288 children (median age 56 - IQR 36-92.5 months, 67.1% male) included, 87 (30.2%) returned positive OFC results, 38 with milk and 49 with egg. The most conservative ED01 was 0.3 mg total protein (IQR 0.03-2.9) for milk and 14.4 mg total protein (IQR 3.6-56.9) for egg. The respective ED05 was 4.2 (IQR 0.9-19.6) mg for milk and 87.7 (IQR 43-179) mg for egg. Such thresholds are, respectively, 1.5 (milk ED01), 1.75 (milk ED05), 72 (egg ED01), and 38.35 (egg ED05) times higher than the currently used thresholds.

CONCLUSIONS

The subpopulation of children allergic to milk and egg, but tolerant to baked proteins, displays higher reactivity thresholds than the general population of children allergic to milk and egg. Their risk stratification, in both individual and population terms, should consider this difference. In baked milk-tolerant children, milk causes reactions at lower doses than egg in our group of egg-tolerant children. This could be associated with the relative harmlessness of egg compared with milk in the determinism of fatal anaphylactic reactions in children.

Predictors and biomarkers of food allergy and sensitization in early childhood

OBJECTIVE

To review existing literature on the early risk factors for and biomarkers of food allergy (FA) and food sensitization (FS) and highlight opportunities for future research that will further the understanding of FA pathogenesis in infancy and toddlerhood.

DATA SOURCES

PubMed search of English-language articles related to FA and atopic disease.

STUDY SELECTIONS

Human studies with outcomes related to FA, FS, and other atopic disease in childhood were selected and reviewed. Studies published after 2015 were prioritized.

RESULTS

The prevalence of FA has greatly increased in recent decades and is now a global public health concern. A complex network of early life risk factors has been associated with development of FA and FS in childhood. Food allergy has a genetic component, but recent evidence suggests that interactions between risk alleles and other environmental exposures are important for disease pathogenesis, potentially through epigenetic mechanisms. Lifestyle factors, such as delivery mode, antibiotic use, and pet exposure also influence FA risk, which may be through their effect on the early life gut microbiome. How these early life risk factors, along with route and timing of antigen exposure, collectively target the developing immune system remains an ongoing and important area of study.

CONCLUSION

The current body of evidence emphasizes the first 1000 days of life as a critical period for FA development. More observational studies and adequately powered clinical trials spanning early pregnancy through childhood are needed to identify novel biomarkers and risk factors that can predict susceptibility toward or protection against FA.

How primary care providers can help prevent food allergies

PURPOSE OF REVIEW

IgE-mediated food allergy rates have increased in recent decades, yet treatment options remain limited. Prevention strategies are thus essential. We will review recent research and consensus guidelines for food allergy prevention.

RECENT FINDINGS

Research has continued to support that early introduction of allergens via the gastrointestinal tract induces tolerance and prevents development of food allergy. In contrast, allergen sensitization may occur via transcutaneous allergen exposure. This is supported by research that shows a decreased risk of food allergy with aggressive treatment of atopic dermatitis. More recent research suggests that transcutaneous sensitization could also be facilitated by frequent emollient use in the absence of atopic dermatitis but definitive research is lacking. Murine models have shown a likely role of dysbiosis, or disruption of the body's normal healthy microbiome, in development of food allergy, yet human studies have yet to show a conclusive benefit of probiotics in the prevention of food allergy.

SUMMARY

Important approaches for food allergy prevention are: introduction of peanut and cooked egg at 4-6 months, early introduction of other allergenic foods, and early diagnosis and treatment of atopic dermatitis (because of a predisposition to food sensitization through the damaged skin barrier). More research is needed to clarify the role, if any, of emollient use and probiotics.

Relevance of Early Introduction of Cow’s Milk Proteins for Prevention of Cow’s Milk Allergy

Food allergy incidence has increased worldwide over the last 20 years. For prevention of food allergy, current guidelines do not recommend delaying the introduction of allergenic foods. Several groundbreaking studies, such as the Learning Early About Peanut Allergy study, showed that the relatively early introduction of this allergenic food between 4–6 months of age reduces the risk of peanut allergy. However, less is known about the introduction of cow’s milk, as many children already receive cow’s-milk-based formula much earlier in life. This can be regular cow’s milk formula with intact milk proteins or hydrolyzed formulas. Several recent studies have investigated the effects of early introduction of cow’s-milk-based formulas with intact milk proteins on the development of cow’s milk allergy while breastfeeding. These studies suggest that depending on the time of introduction and the duration of administration of cow’s milk, the risk of cow’s milk allergy can be reduced (early introduction) or increased (very early introduction followed by discontinuation). The aim of this narrative review is to summarize these studies and to discuss the impact of early introduction of intact cow’s milk protein—as well as hydrolyzed milk protein formulas—and the development of tolerance versus allergy towards cow’s milk proteins.

Current Strategies to Modulate Regulatory T Cell Activity in Allergic Inflammation

Over the past decades, atopic diseases, including allergic rhinitis, asthma, atopic dermatitis, and food allergy, increased strongly worldwide, reaching up to 50% in industrialized countries. These diseases are characterized by a dominating type 2 immune response and reduced numbers of allergen-specific regulatory T (Treg) cells. Conventional allergen-specific immunotherapy is able to tip the balance towards immunoregulation. However, in mouse models of allergy adaptive transfer of Treg cells did not always lead to convincing beneficial results, partially because of limited stability of their regulatory phenotype activity. Besides genetic predisposition, it has become evident that environmental factors like a westernized lifestyle linked to modern sanitized living, the early use of antibiotics, and the consumption of unhealthy foods leads to epithelial barrier defects and dysbiotic microbiota, thereby preventing immune tolerance and favoring the development of allergic diseases. Epigenetic modification of Treg cells has been described as one important mechanism in this context. In this review, we summarize how environmental factors affect the number and function of Treg cells in allergic inflammation and how this knowledge can be exploited in future allergy prevention strategies as well as novel therapeutic approaches.

Early Introduction of Allergenic Foods and the Prevention of Food Allergy

The increasing prevalence of food allergies is a growing public health problem. For children considered high risk of developing food allergy (particularly due to the presence of other food allergies or severe eczema), the evidence for the early introduction of allergenic foods, and in particular peanut and egg, is robust. In such cases, the consensus is clear that not only should such foods not be delayed, but that they should be introduced at approximately 4 to 6 months of age in order to minimize the risk of food allergy development. The early introduction of allergenic foods appears to be an effective strategy for minimizing the public health burden of food allergy, though further studies on the generalizability of this approach in low-risk populations is needed.

Cow's Milk Antigens Content in Human Milk: A Scoping Review

The functionality of breast milk in terms of immunity is well-known. Despite this, a significant proportion of breastfed infants exhibit sensitization to different potentially allergenic proteins and clinical reactivity (including anaphylaxis) early in life and before the introduction of complementary feeding for the first time. The potential induction of early oral tolerance to overcome early allergic sensitization through exposure to allergens in breast milk also remains controversial and not yet well-established. The objective of this scoping review is to provide a critical appraisal of knowledge about the content of cow's milk antigens in human milk. The amount of dietary derived milk antigens found in human milk and the analytical methodologies used to detect and quantify these antigens, the allergic status of the mother, the stage of lactation, the time of sampling (before or after ingestion of food), and the impact of human milk allergen on the infant were the outcomes that were assessed. Allergy risk was explored in all reviewed studies and could help to better elucidate its role in the context of allergic disease development. According to the included literature, we can conclude that there are mainly fragments derived from bovine proteins in human milk, and the presence of potentially allergenic molecules is greater in the milk of mothers with an allergic tendency. A clear relationship between maternal diet and allergen content in breast milk could not be firmly concluded though. Also, infants receiving milk from human milk banks, where donor milk is pasteurized for preservation, may be subject to greater risk of allergy development, especially for β-lactoglobulin.

Dietary exposures and allergy prevention in high-risk infants

Infants at high risk for developing a food allergy have either an atopic condition (such as eczema) themselves or an immediate family member with such a condition. Breastfeeding should be promoted and supported regardless of issues pertaining to food allergy prevention, but for infants whose mothers cannot or choose not to breastfeed, using a specific formula (i.e., hydrolyzed formula) is not recommended to prevent food allergies. When cow's milk protein formula has been introduced in an infant's diet, make sure that regular ingestion (as little as 10 mL daily) is maintained to prevent loss of tolerance. For high-risk infants, there is compelling evidence that introducing allergenic foods early-at around 6 months, but not before 4 months of age-can prevent common food allergies, and allergies to peanut and egg in particular. Once an allergenic food has been introduced, regular ingestion (e.g., a few times a week) is important to maintain tolerance. Common allergenic foods can be introduced without pausing for days between new foods, and the risk for a severe reaction at first exposure in infancy is extremely low. Pre-emptive in-office screening before introducing allergenic foods is not recommended. No recommendations can be made at this time about the role of maternal dietary modification during pregnancy or lactation, or about supplementing with vitamin D, omega 3, or pre- or probiotics as means to prevent food allergy.