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

Prevention of Non-peanut Food Allergies

PURPOSE OF REVIEW

The purpose of this review article is to discuss the recent literature around methods of prevention of food allergies other than peanut allergy.

RECENT FINDINGS

While the most robust data to date exists for peanut, there are emerging studies suggesting a beneficial effect to early introduction of cooked egg, and cow's milk as well. While the literature is sparse for other allergens such as tree nuts, finned fish, and shellfish, the mechanism of sensitization is thought to be the same and no study to date has demonstrated a harm with allergenic introduction in the 4-6 months of age window (nor has there been level 1 evidence of benefit to delay of such allergens). This strategy is safe, and pre-emptive testing is not required prior to allergenic solid introduction. All allergenic solids should be introduced at around 6, but not before 4, months of age in infants at high risk.

Can dietary strategies in early life prevent childhood food allergy? A report from two iFAAM workshops

Food allergy affects a small but significant number of children and adults. Food allergy is responsible for considerable morbidity and is the commonest cause of anaphylaxis in children. One of the aims of the European Union-funded "Integrated Approaches to Food Allergen and Allergy Risk Management" (iFAAM) project was to improve our understanding of the best way to prevent the development of food allergy. Groups within the project worked on integrating the current prevention evidence base as well as generating new data to move our understanding forward. This paper from the iFAAM project is a unique addition to the literature on this topic as it not only outlines the recently published randomized controlled trials (as have previous reviews) but also summarizes two iFAAM-associated project workshops. These workshops focused on how we may be able to use dietary strategies in early life to prevent the development of food allergy and summarized the range of opinions amongst experts in this controversial area.

Timing of Introduction, Sensitization, and Allergy to Highly Allergenic Foods at Age 3 Years in a General-Population Canadian Cohort

BACKGROUND

Early dietary introduction of highly allergenic foods has been associated with decreased risk of food allergy in high-risk infants.

OBJECTIVE

Early introduction of highly allergenic foods for lower risk infants was examined using Canadian Healthy Infant Longitudinal Development (CHILD) Study data.

METHODS

CHILD participants were recruited from the general population before birth. Every 6 months, caregivers reported food introduction and allergic reactions. At ages 1 and 3 years, sensitization to peanut, egg, and cow's milk was measured by skin prick testing (SPT) and atopic dermatitis diagnosed at clinical visits. Multivariable logistic regression was used to examine associations between timing of introduction to peanut, egg, and cow's milk and the presence at 3 years of sensitization (positive SPT) and probable clinical IgE-mediated allergy (sensitization with no current consumption and convincing history of allergic reaction to the specific food).

RESULTS

Among 2669 CHILD participants at age 3 years, 101 (3.80%) showed sensitization to peanut, 59 (2.21%) to egg, and 30 (1.12%) to cow's milk; 46 (1.78%) showed probable clinical IgE-mediated allergy to peanut, 4 (0.16%) to egg, and 2 (0.08%) to cow's milk. Infants introduced to peanut after 12 months had increased odds of sensitization (odds ratio [OR]: 2.38, 95% confidence interval [CI]: 1.39-4.07) and probable clinical allergy (OR: 4.04, 95% CI: 1.66-9.85) to peanut at 3 years. Associations persisted after exclusion of high-risk infants with moderate-to-severe atopic dermatitis in the first year/egg sensitization at 1 year.

CONCLUSIONS

General-population infants introduced to peanut after age 12 months were more likely to have sensitization and probable clinical allergy to peanut at 3 years.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

It's Not Mom's Fault: Prenatal and Early Life Exposures that Do and Do Not Contribute to Food Allergy Development

Thus far, the most effective strategy for the prevention of food allergy is early introduction of allergenic solids to at-risk infants. Early skin moisturization may have a role in food allergy prevention. There is insufficient evidence for hydrolyzed formula as a means of allergy prevention. Studies on vitamin D, omega 3, and probiotic supplementation; breastfeeding; early infant dietary diversity; and maternal peanut ingestion during pregnancy and breastfeeding are inconsistent.

Raw Cow's Milk Reduces Allergic Symptoms in a Murine Model for Food Allergy-A Potential Role For Epigenetic Modifications

Epidemiological studies identified raw cow's milk consumption as an important environmental exposure that prevents allergic diseases. In the present study, we investigated whether raw cow's milk has the capacity to induce tolerance to an unrelated, non-milk, food allergen. Histone acetylation of T cell genes was investigated to assess potential epigenetic regulation. Female C3H/HeOuJ mice were sensitized and challenged to ovalbumin. Prior to sensitization, the mice were treated with raw milk, processed milk, or phosphate-buffered saline for eight days. Allergic symptoms were assessed after challenge and histone modifications in T cell-related genes of splenocyte-derived CD4⁺ T cells and the mesenteric lymph nodes were analyzed after milk exposure and after challenge. Unlike processed milk, raw milk decreased allergic symptoms. After raw milk exposure, histone acetylation of Th1-, Th2-, and regulatory T cell-related genes of splenocyte-derived CD4⁺ T cells was higher than after processed milk exposure. After allergy induction, this general immune stimulation was resolved and histone acetylation of Th2 genes was lower when compared to processed milk. Raw milk reduces allergic symptoms to an unrelated, non-milk, food allergen in a murine model for food allergy. The activation of T cell-related genes could be responsible for the observed tolerance induction, which suggested that epigenetic modifications contribute to the allergy-protective effect of raw milk.

Infant Feeding, Vitamin D and IgE Sensitization to Food Allergens at 6 Years in a Longitudinal Icelandic Cohort

Nordic Nutrition Recommendations (NNR) recommend exclusive breastfeeding until 6 months, partial breastfeeding until 1 year or longer and irrespective of breastfeeding, avoiding solid foods before 4 months. Strong evidence was found for benefits of breastfeeding regarding growth and infections but limited/inconclusive evidence regarding atopic disease and asthma. Vitamin D is of special interest in the Nordic diet. The aim of this prospective study was to compare infant feeding and vitamin D between immunoglobulin E (IgE) sensitized (n = 14) and non-sensitized (n = 130) children at 6 years. Information on diet and vitamin D supplement use were collected with dietary recall (<5 months), 1-d food records (5 and 6 months) and 3-d weighed food records (12 months and 6 years). Serum-specific IgE-antibodies against milk, egg, cod, wheat, soy and peanut (cut-off specific IgE ≥ 0.35 kUA/L) were measured at 6 years and serum 25-hydroxyvitamin D at 12 months and 6 years. At 4 months, 57% of IgE sensitized vs. 23% of non-sensitized children (p < 0.01) had received solid food. At 12 months, IgE sensitized children had a lower intake of vitamin D (median (25th, 75th percentiles): 3.9 μg/d (3.2, 7.2) vs. 8.1 μg/d (4.4, 12.3), p = 0.03) and at 6 years, fewer used vitamin D supplements regularly (23% vs. 56%, p = 0.03). Introduction of solid foods prior to 4 months increased the odds of IgE-sensitization, OR = 4.9 (95%, CI = 1.4–16.6) and vitamin D supplement at 6 years decreased the odds of IgE-sensitization, OR = 0.2 (95%, CI = 0.1–0.98), adjusting for maternal smoking. These observations support the NNR in their recommendation against introducing complementary solid foods before the age of 4 months. Furthermore, they support encouraging vitamin D intake for young children at northern latitudes.

Prevention of Food Allergy: The Significance of Early Introduction

Over the last two decades, the prevalence of food allergies has registered a significant increase in Westernized societies, potentially due to changes in environmental exposure and lifestyle. The pathogenesis of food allergies is complex and includes genetic, epigenetic and environmental factors. New evidence has highlighted the role of the intestinal microbiome in the maintenance of the immune tolerance to foods and the potential pathogenic role of early percutaneous exposure to allergens. The recent increase in food allergy rates has led to a reconsideration of prevention strategies for atopic diseases, mainly targeting the timing of the introduction of solid foods into infants' diet. Early recommendation for high atopy risk infants to delay the introduction of potential food allergens, such as cow's milk, egg, and peanut, until after the first year of life, has been rescinded, as emerging evidence has shown that these approaches are not effective in preventing food allergies. More recently, high-quality clinical trials have suggested an opposite approach, which promotes early introduction of potential food allergens into infants' diet as a means to prevent food allergies. This evidence has led to the production of new guidelines recommending early introduction of peanut as a preventive strategy for peanut allergy. However, clinical trials investigating whether this preventive dietary approach could also apply to other types of food allergens have reported ambiguous results. This review focuses on the latest high-quality evidence from randomized controlled clinical trials examining the timing of solid food introduction as a strategy to prevent food allergies and also discusses the possible implications of early complementary feeding on both the benefits and the total duration of breastfeeding.

Timing of Food Introduction and the Risk of Food Allergy

Given that the prevalence of pediatric IgE-mediated food allergies (FA) has followed a substantive increase in recent decades, nowadays, a research challenge is to establish whether the weaning strategy can have a role in FA prevention. In recent decades, several studies have demonstrated that delayed exposure to allergenic foods did not reduce the risk of FA, leading to the publication of recent guidelines which recommend against delaying the introduction of solid foods after 4–6 months of age, both in high- and low-risk infants, in order to prevent food allergy. In the present review, focusing on cow’s milk protein, hen’s eggs, peanuts, soy, wheat and fish, we describe the current scientific evidence on the relationship between timing of these foods’ introduction in infants’ diet and allergy development.

How to prevent food allergy during infancy: what has changed since 2013?

PURPOSE OF REVIEW

The purpose of this review is to summarize recent studies and emerging consensus guidelines regarding food allergy prevention in infants of the past 5 years.

RECENT FINDINGS

Prior to 2013, the general consensus regarding prevention of food allergy in infants was to recommend delayed introduction or complete avoidance of commonly allergenic foods, such as milk, egg and peanut. However, in the past 5 years, several landmark studies have been conducted, particularly with peanut. The results of these studies have led to a paradigm shift from recommending delayed introduction to early introduction and frequent feeding of highly allergenic foods such as peanut, with hopes of achieving primary and secondary prevention of food allergy in infants.

SUMMARY

Recent clinical trials have demonstrated that early introduction and frequent feeding, rather than delayed introduction or complete avoidance, of commonly allergenic foods plays a critical role in preventing food allergy in infants. More studies are required to risk-stratify infants by personal and family atopic history to tailor guidelines for groups with inherently different risks. The universal acceptance of the guidelines and their application outcome are still to be determined.

Age at introduction to complementary solid food and food allergy and sensitization: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

An infant's age at introduction of complementary solids may contribute to food allergy. We aimed to synthesize the literature on the association between age at introduction of complementary solids, excluding milk products, and food allergy and sensitization.

DESIGN

We searched the electronic databases PubMed and EMBASE (January 1946-February 2017) using solid food, allergy and sensitization terms.

METHODS

Two authors selected papers according to inclusion criteria, identifying 16 cohort studies, 1 case-control study and 8 randomized controlled trials (RCTs). Pooled effects across studies were estimated using random-effects meta-analysis.

RESULTS

Cohort studies-Introducing complementary solids at age ≥ 4 months vs <4 months was not associated with food allergy (OR 1.22; 95% CI, 0.76-1.96) but was associated with food sensitization (OR 1.93; 95% CI 1.57-2.38). First exposure from age 4 to 6 months vs <4 months was not associated with food allergy (OR 1.01; 95% CI, 0.64-1.60) but was associated with food sensitization (OR 2.46; 95% CI 1.55-3.86). Randomized controlled trials-Egg exposure from age 4 months was associated with reduced egg allergy (OR 0.63, 95% CI, 0.44-0.90) and sensitization (OR 0.76, 95% CI, 0.51-0.95). Peanut exposure from age 4 months compared to delayed exposure was associated with reduced peanut allergy (OR 0.28, 95% CI 0.14-0.57).

CONCLUSIONS

We found no evidence from observational studies that introducing solids before 4 months protected against food allergy, but there was evidence for protection against food sensitization. From RCTs, introducing egg from 4 to 6 months and peanut from 4 to 11 months reduced the risk of egg allergy, peanut allergy and egg sensitization. PROSPERO systematic review registry (CRD42016033473).

The Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children: The Role of Maternal Dietary Restriction, Breastfeeding, Hydrolyzed Formulas, and Timing of Introduction of Allergenic Complementary Foods

This clinical report updates and replaces a 2008 clinical report from the American Academy of Pediatrics, which addressed the roles of maternal and early infant diet on the prevention of atopic disease, including atopic dermatitis, asthma, and food allergy. As with the previous report, the available data still limit the ability to draw firm conclusions about various aspects of atopy prevention through early dietary interventions. Current evidence does not support a role for maternal dietary restrictions during pregnancy or lactation. Although there is evidence that exclusive breastfeeding for 3 to 4 months decreases the incidence of eczema in the first 2 years of life, there are no short- or long-term advantages for exclusive breastfeeding beyond 3 to 4 months for prevention of atopic disease. The evidence now suggests that any duration of breastfeeding ≥3 to 4 months is protective against wheezing in the first 2 years of life, and some evidence suggests that longer duration of any breastfeeding protects against asthma even after 5 years of age. No conclusions can be made about the role of breastfeeding in either preventing or delaying the onset of specific food allergies. There is a lack of evidence that partially or extensively hydrolyzed formula prevents atopic disease. There is no evidence that delaying the introduction of allergenic foods, including peanuts, eggs, and fish, beyond 4 to 6 months prevents atopic disease. There is now evidence that early introduction of peanuts may prevent peanut allergy.

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.

The skin as a target for prevention of the atopic march

OBJECTIVE

Allergic diseases have increased dramatically in the developed world during the past few decades, yet the understanding of risk factors and effective prevention approaches remain limited. In this review, we summarize the evidence supporting the hypothesis that skin-barrier impairment and early-life atopic dermatitis (AD) could play a causal role in the development of sensitization and subsequent food allergies and allergic airways disease (allergic asthma and rhinitis). We further discuss the potential to target the skin barrier as a means to lower the incidence of allergic disease.

DATA SOURCES

Review of published literature.

STUDY SELECTIONS

Narrative.

RESULTS

There is a strong link between AD and sensitization, food allergy, asthma, and allergic rhinitis, particularly AD that is severe and commences in the first 6 months of life. There also is emerging evidence that regular use of prophylactic emollients can significantly decrease the expression of AD, at least while treatment continues. Studies are exploring whether decreased AD expression might modulate the allergic response at a more fundamental level and potentially alter the association between early-life AD and subsequent development of food allergy and allergic airways disease.

CONCLUSION

Although at this point there is only indirect evidence that early-life emollient use might prevent AD and food allergy, early studies are encouraging. The results of high-quality prevention trials that are in progress are eagerly anticipated. If found to be effective, then neonatal emollient use could be a simple public health measure to lower the incidence of AD, food allergies, and allergic airways disease in future generations.

Solid Food Introduction and the Development of Food Allergies

The rise of food allergy in childhood, particularly among developed countries, has a significant weight on public health and involves serious implications for patients' quality of life. Even if the mechanisms of food tolerance and the complex interactions between the immune system and environmental factors are still mainly unknown, pediatricians have worldwide implemented preventive measures against allergic diseases. In the last few decades, the prevention of food allergy has tracked various strategies of complementary feeding with a modification of international guidelines from delayed introduction to early weaning. Current evidence shows that complementary foods, including allergenic ones, should be introduced into diet after four months, or even better, following World Health Organization advice, around six months irrespective of risk for allergy of the individual. The introduction of peanut is recommended before 12 months of age among infants affected by severe eczema and/or egg allergy to diminish the occurrence of peanut allergy in countries with high peanut consumption. The introduction of heated egg at 6⁻8 months of age may reduce egg allergy. Infants at high risk of allergy similarly to healthy children should introduce complementary foods taking into account family and cultural preferences.

The health and economic outcomes of early egg introduction strategies

BACKGROUND

Studies suggest early egg introduction (EEI) in the first year of life is associated with reduced risk of developing egg allergy. No US recommendations exist regarding optimally implementing EEI.

METHODS

Using simulation and Markov modelling over a 20-year horizon, we explored optimal EEI strategies applied to US, European and Canadian populations, comparing screening of high-risk infants (skin prick testing [SPT] or serum-specific IgE[sIgE]) before introducing cooked egg at 6 months of life vs egg introduction at home, without screening, for all infants.

RESULTS

A no-screen approach dominated egg SPT screening of high-risk infants with early-onset eczema. Base model per-patient incremental costs of SPT were $6865 US dollars (USD), 6801 euros and $10 610 Canadian dollars (CAD). For egg sIgE screening in primary care settings, base model incremental costs were $16 722 USD, 18 072 euros and $28 193 CAD. As the simulation concluded 2.5% were egg allergic without screening vs 9.5%, 12% and 21.4% of children undergoing SPT, delayed introduction or sIgE screening. Incremental societal costs from screening reached $2 009 351 175 USD for SPT and $4 894 445 790 USD for sIgE testing. In sensitivity analyses, if the risk of reaction with initial egg ingestion was ≥22.5%, SPT before EEI became a preferred strategy. A no-screen approach dominated both EEI of raw pasteurized egg and delayed cooked egg introduction approaches.

CONCLUSIONS

Assuming initial reaction rates < 22.5%, a no-screening EEI cooked egg approach has superior health and economic benefits in terms of number of egg allergy cases prevented and total healthcare costs vs screening testing.

Early introduction of foods to prevent food allergy

Food allergy is a growing public health problem, and in many affected individuals, the food allergy begins early in life and persists as a lifelong condition (e.g., peanut allergy). Although early clinical practice guidelines recommended delaying the introduction of peanut and other allergenic foods in children, this may have in fact contributed to the dramatic increase in the prevalence of food allergy in recent decades. In January 2017, new guidelines on peanut allergy prevention were released which represented a significant paradigm shift in early food introduction. Development of these guidelines was prompted by findings from the Learning Early About Peanut Allergy study—the first randomized trial to investigate early allergen introduction as a strategy to prevent peanut allergy. This article will review and compare the new guidelines with previous guidelines on food introduction, and will also review recent evidence that has led to the paradigm shift in early food introduction.

Release of Major Peanut Allergens from Their Matrix under Various pH and Simulated Saliva Conditions-Ara h2 and Ara h6 Are Readily Bio-Accessible

The oral mucosa is the first immune tissue that encounters allergens upon ingestion of food. We hypothesized that the bio-accessibility of allergens at this stage may be a key determinant for sensitization. Light roasted peanut flour was suspended at various pH in buffers mimicking saliva. Protein concentrations and allergens profiles were determined in the supernatants. Peanut protein solubility was poor in the pH range between 3 and 6, while at a low pH (1.5) and at moderately high pHs (>8), it increased. In the pH range of saliva, between 6.5 and 8.5, the allergens Ara h2 and Ara h6 were readily released, whereas Ara h1 and Ara h3 were poorly released. Increasing the pH from 6.5 to 8.5 slightly increased the release of Ara h1 and Ara h3, but the recovery remained low (approximately 20%) compared to that of Ara h2 and Ara h6 (approximately 100% and 65%, respectively). This remarkable difference in the extraction kinetics suggests that Ara h2 and Ara h6 are the first allergens an individual is exposed to upon ingestion of peanut-containing food. We conclude that the peanut allergens Ara h2 and Ara h6 are quickly bio-accessible in the mouth, potentially explaining their extraordinary allergenicity.

Early Introduction of Egg and the Development of Egg Allergy in Children: A Systematic Review and Meta-Analysis

BACKGROUND

The timing of the introduction of egg to an infant's diet is of current interest, as new evidence raises questions regarding the benefit of delaying egg introduction. The objective of this study was to systematically review the existing literature regarding the effect of the early introduction of egg on the development of egg allergy.

METHODS

Literature searches were conducted in MEDLINE, EMBASE, and CENTRAL, and trial protocols were searched in Meta Register and OpenGREY. Only randomized controlled trials (RCTs) comparing early (between 3 and 6 months of age) egg introduction to no early introduction were included. The primary outcome was the development of egg allergy.

RESULTS

Of the 416 articles identified and screened, 6 RCTs met the eligibility criteria for data extraction. Allergic outcomes were evaluated in a total of 3,032 participants. A low to moderate level of evidence showed a benefit of the early introduction of egg (relative risk, RR 0.60, 95% CI 0.44-0.82, p = 0.002, mild heterogeneity, I2 = 23%). The absolute risk reduction for a population with an incidence of egg allergy of 9.3% was 37 fewer cases (95% CI 17-52) per 1,000 people. Consumption of < 4,000 mg/week of egg protein had a greater preventive effect than a higher dose.

CONCLUSION

This systematic review and meta-analysis showed an association between the early introduction of egg and a lower risk of egg allergy. Furthermore, the nature and dose of egg protein exposure may play a role. These findings should be addressed in the context of primary studies.

Egg introduction during complementary feeding according to allergic risk: not just for peanuts!

The relationship between the timing of introduction of complementary foods and later allergy is a topic of current discussion. Although the European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) has recently recommended that potentially allergenic foods may be introduced when complementary feeding is commenced, any time after 4 months, recommendations about egg introduction would be needed mainly for infants with high risk of developing food allergy. Before the first administration in these infants an adequate topical therapy and an evaluation of whole egg-specific IgE serum antibody levels or skin prick tests for egg should be recommended.

Food allergy and anaphylaxis

Anaphylaxis is a severe and potentially life-threatening allergic reaction. There are numerous potential causes, with food allergy being the leading cause in children and the focus of this review. Most reactions involve an IgE-mediated mechanism, although non-IgE-mediated and nonimmunologic reactions can occur. Various cofactors to be discussed can place certain individuals at an increased risk of severe or fatal anaphylaxis. The clinical manifestations of anaphylaxis are broad and may involve multiple body systems. Diagnosis of food-related anaphylaxis is primarily based on signs and symptoms and supported, wherever possible, by identification and confirmation of a culprit food allergen. First-line treatment of anaphylaxis is intramuscular administration of epinephrine. Long-term management is generally focused on strict allergen avoidance and more recently on food desensitization using immunotherapy. This review provides an overview of anaphylaxis with a specific focus on food allergy.

The challenges of preventing food allergy: Lessons learned from LEAP and EAT

OBJECTIVE

To highlight challenges associated with this novel preventive strategy.

DATA SOURCES

The Learning Early About Peanuts (LEAP) and Enquiring About Tolerance (EAT) Studies, with reference to other oral tolerance induction studies.

STUDY SELECTIONS

Randomized clinial trials seeking to prevent food allergy through allergen introduction in infancy.

RESULTS

Oral tolerance induction programs that use a regimen of consumption of 2 g/week of protein are effective in preventing peanut and egg allergy. LEAP findings suggest oral tolerance induction is allergen specific. Adding peanut and other common food allergens (egg, fish, sesame, milk) to the infant diet has no adverse nutritional or growth effects and does not increase rates of food allergy. Breastfeeding rates are not adversely affected by these interventions. In the Western world, nonwhite children have the highest risk of food allergy, but their families are the least likely to participate in oral tolerance induction programs.

CONCLUSION

Many challenges must be overcome to implement successful food allergy prevention strategies. Allergy testing of high-risk infants (those with moderate to severe eczema and/or egg allergy) before commencing oral tolerance induction is desirable, but access is not universal. Dietary interventions would ideally be implemented in infancy before allergic sensitization and allergy occur, using a program that provides protection against multiple common allergens. Further research and consensus with regard to food preparations, target populations, dosing regimens, and preparations and clearly defined adherence are now required.

Prevalence of Self-Reported Food Allergy in Six Regions of Inner Mongolia, Northern China: A Population-Based Survey

Background

The aim of this study was to determine the prevalence of self-reported food allergy in 6 regions of Inner Mongolia, northern China.

Material/Methods

A random cluster sampling population study using a field questionnaire was distributed to 4714 individuals in 6 regions within Inner Mongolia, northern China; the study included ethnic Mongol minorities and Chinese Han populations. The questionnaire obtained data on ethnicity, age, sex, level of education, income, socioeconomic status, rural versus urban location, medical and family history, and food allergy.

Results

There were 4441 (73.5%) completed questionnaires. The prevalence of self-reported food allergy was 18.0% (15.2% men; 20.6% women) and was age-related, being significantly greater in children compared with adults (38.7% vs. 11.9%) (P<0.001). There was a significant difference in self-reported food allergy between rural and urban populations (14.6% vs. 21.4%) (P<0.001) and between Mongolian and Han populations (20.8% vs. 15.8%) (P<0.001). Socioeconomic status, higher education level, and increased family income were significantly correlated with the prevalence of food allergy (P<0.001). Participants with allergic diseases and atopic family history were at increased risk (OR>1, P<0.001). There were no significant associations between the prevalence of food allergy and birth history, infant feeding, and duration of breastfeeding.

Conclusions

An increase in the prevalence of self-reported food allergy was found in the Inner Mongolia region of northern China, which was greater in urban areas compared with rural areas.

Advances in the approach to the patient with food allergy

Advances in food allergy diagnosis, management, prevention, and therapeutic interventions have been significant over the past 2 decades. Evidence-based national and international guidelines have streamlined food allergy diagnosis and management, whereas paradigm-shifting work in primary prevention of peanut allergy has resulted in significant modifications in the approach to early food introduction in infants and toddlers. Innovative investigation of food allergy epidemiology, systems biology, effect, and management has provided important insights. Although active therapeutic approaches to food allergy remain experimental, progress toward licensed therapies has been substantial. Mechanistic understanding of the immunologic processes underlying food allergy and immunotherapy will inform the future design of therapeutic approaches targeting the food-induced allergic response. Global strategies to mitigate the substantial medical, economic, and psychosocial burden of food allergy in affected subjects and families will require engagement of stakeholders across multiple sectors in research, health care, public health, government, educational institutions, and industry. However, the relationship between the well-informed allergy care provider and the patient and family remains fundamental for optimizing the care of the patient with food allergy.

Caregiver and expecting caregiver support for early peanut introduction guidelines

BACKGROUND

Recent guidelines recommend early peanut introduction (EPI) beginning around 4 to 6 months of age in infants with severe eczema and/or egg allergy and around 6 months for all other infants. Caregiver preferences for such practices are unknown.

OBJECTIVE

To determine levels of support for early allergenic solid food recommendations among new and expecting caregivers of infants at risk for peanut allergy.

METHODS

We explored preferences for EPI and in-office allergy risk assessment (IRA) through a nationally representative survey of expecting (n = 1,000) and new caregivers of infants younger than 1 year (n = 1,000).

RESULTS

Among a primarily female (99.7%), married (80.3%), and white (74.4%) sample, 29% had no or vague awareness of the new guidelines, 61% had no or minimal concern for their child developing food allergy, but 54% felt timing of food introduction has moderate to strong importance for developing food allergy. Only 31% expressed willingness for EPI before or around 6 months of age, with 40% reporting willingness to introduce peanut after 11 months of age, similar to tree nuts and seafood. However, 60% reported willingness to introduce egg before 8 months of age. A total of 51% and 56.8% were unwilling to allow IRA methods, such as skin testing and oral challenge, before 11 months of age, respectively. Odds of willingness to delay peanut introduction (odds ratio, 0.79; 95% confidence interval, 0.65-0.96) and undergo challenge (odds ratio, 0.67; 95% confidence interval, 0.54-0.82) after 6 months of age were lower among expecting caregivers.

CONCLUSION

Among new and expecting caregivers, there is poor current willingness and questionable support for early allergenic solid food recommendations, including IRA before introduction. Willingness was better among expecting vs current caregivers. These trends underscore a need for broader formal implementation planning to facilitate early allergen introduction and maximize its preventive benefits.

The Role of Food Challenges in Clinical Practice

Food challenges are the criterion standard for establishing the presence or absence of food allergy. However, they remain underused because of their resource-intensive nature, inadequate reimbursement, and concern for the risk of anaphylaxis. Here, we review indications for performing food challenges, including scenarios of uncertain diagnosis, quality-of-life effects following food challenges, and the impact on office practice including coding and reimbursement issues. Demand for food challenges is likely to increase and allergists should be capable of providing this service to their patients when indicated.

Early introduction of allergenic foods for the prevention of food allergy from an Asian perspective-An Asia Pacific Association of Pediatric Allergy, Respirology & Immunology (APAPARI) consensus statement

Emerging evidence for the early introduction of allergenic foods for the prevention of food allergies, such as peanut allergy in Western populations, has led to the recent publication of guidelines in the USA and Europe recommending early peanut introduction for high-risk infants with severe eczema or egg allergy. Peanut allergy is, however, much less prevalent in Asia compared to the West. Varying patterns of food allergy are seen even within Asian countries-such as a predominance of wheat allergy in Japan and Thailand and shellfish allergy in Singapore and the Philippines. Customs and traditions, such as diet and infant feeding practices, also differ between Asian populations. Hence, there are unique challenges in adapting guidelines on early allergenic food introduction to the Asian setting. In this paper, we review the evidence and discuss the possible approaches to guide the timely introduction of allergenic food in high-risk infants in Asia.

The Value of Food Allergy Prevention in Clinical Practice in Pediatrics: Targeting Early Life

Food allergies are common and increasing in prevalence, representing a major health concern in many countries around the world. In an effort to diminish the burden of food allergy, many research studies have focused on prevention, and recent findings have revolutionized the way we introduce allergenic foods in early life. We discuss the role of early allergenic food introduction and the value of food allergy prevention in this manuscript.

Food allergy

Food allergies manifest in a variety of clinical conditions within the gastrointestinal tract, skin and lungs, with the most dramatic and sometimes fatal manifestation being anaphylactic shock. Major progress has been made in basic, translational and clinical research, leading to a better understanding of the underlying immunological mechanisms that lead to the breakdown of clinical and immunological tolerance against food antigens, which can result in either immunoglobulin E (IgE)-mediated reactions or non-IgE-mediated reactions. Lifestyle factors, dietary habits and maternal-neonatal interactions play a pivotal part in triggering the onset of food allergies, including qualitative and quantitative composition of the microbiota. These factors seem to have the greatest influence early in life, an observation that has led to the generation of hypotheses to explain the food allergy epidemic, including the dual-allergen exposure hypothesis. These hypotheses have fuelled research in preventive strategies that seek to establish desensitization to allergens and/or tolerance to allergens in affected individuals. Allergen-nonspecific therapeutic strategies have also been investigated in a number of clinical trials, which will eventually improve the treatment options for patients with food allergy.

Recent advancement to prevent the development of allergy and allergic diseases and therapeutic strategy in the perspective of barrier dysfunction

Therapeutic strategy in late 20th century to prevent allergic diseases was derived from a conceptual framework of allergens elimination which was as same as that of coping with them after their onset. Manifold trials were implemented; however, most of them failed to verify the effectiveness of their preventive measures. Recent advancement of epidemiological studies and cutaneous biology revealed epidermal barrier dysfunction plays a major role of allergen sensitization and development of atopic dermatitis which ignites the inception of allergy march. For this decade, therapeutic strategy to prevent the development of food allergy has been confronted with a paradigm shift from avoidance and delayed introduction of allergenic foods based on the theoretical concept to early introduction of them based on the clinical and epidemiological evidences. Especially, prevention of peanut allergy and egg allergy has been established with the highest evidence verified by randomized controlled trials, although application in clinical practice should be done with attention. This paradigm shift concerning food allergy was also due to the discovery of cutaneous sensitization risk of food allergens for an infant with eczema revealed by prospective studies. Here we have recognized the increased importance of prevention of eczema/atopic dermatitis in infancy. Two randomized controlled trials using emollients showed successful results in prevention of atopic dermatitis in infancy; however, longer term safety and prognosis including allergy march should be pursued. To establish more fundamental strategy for prevention of the development of allergy, further studies clarifying the mechanisms of interaction between barrier dysfunction and microbial milieu are needed with macroscope to understand the relationship between allergic diseases and a diversity of environmental influences.

Dietary intervention for preventing food allergy in children

PURPOSE OF REVIEW

In the past decade, food allergy has been increasingly recognized as an important public health issue. The role of maternal and infant diet in the development of food allergy has been a major focus of research throughout this period. Recently, research in this area has moved from observational studies to intervention trials, and the findings from these trials have started to influence infant feeding guidelines. In this article, we review recent studies of dietary interventions for preventing food allergy, summarize current knowledge and discuss future research directions.

RECENT FINDINGS

The latest result from an intervention trial shows that introduction of peanut in the first year of life reduces the risk of peanut allergy in high-risk infants. A systematic review and meta-analysis of intervention trials also suggests a protective effect of egg introduction from around 4 to 6 months of age for reducing the risk of egg allergy, with most studies conducted in high-risk infants. Despite several intervention trials involving modifications to the maternal diet, the effect of maternal diet during pregnancy and lactation in preventing food allergy remains unclear.

SUMMARY

Earlier introduction of allergenic foods is a promising intervention to reduce the risk of some food allergies in high-risk infants. Further work is needed to improve knowledge of how to prevent food allergy in the general population.

Eggs early in complementary feeding increase choline pathway biomarkers and DHA: a randomized controlled trial in Ecuador

Background: Choline status has been associated with stunting among young children. Findings from this study showed that an egg intervention improved linear growth by a length-for-age z score of 0.63.Objective: We aimed to test the efficacy of eggs introduced early in complementary feeding on plasma concentrations of biomarkers in choline pathways, vitamins B-12 and A, and essential fatty acids.Design: A randomized controlled trial, the Lulun ("egg" in Kichwa) Project, was conducted in a rural indigenous population of Ecuador. Infants aged 6-9 mo were randomly assigned to treatment (1 egg/d for 6 mo; n = 80) and control (no intervention; n = 83) groups. Socioeconomic data, anthropometric measures, and blood samples were collected at baseline and endline. Household visits were made weekly for morbidity surveillance. We tested vitamin B-12 plasma concentrations by using chemiluminescent competitive immunoassay and plasma concentrations of choline, betaine, dimethylglycine, retinol, essential fatty acids, methionine, dimethylamine (DMA), trimethylamine, and trimethylamine-N-oxide (TMAO) with the use of liquid chromatography-tandem mass spectrometry.Results: Socioeconomic factors and biomarker concentrations were comparable at baseline. Of infants, 11.4% were vitamin B-12 deficient and 31.7% marginally deficient at baseline. In adjusted generalized linear regression modeling, the egg intervention increased plasma concentrations compared with control by the following effect sizes: choline, 0.35 (95% CI: 0.12, 0.57); betaine, 0.29 (95% CI: 0.01, 0.58); methionine, 0.31 (95% CI: 0.03, 0.60); docosahexaenoic acid, 0.43 (95% CI: 0.13, 0.73); DMA, 0.37 (95% CI: 0.37, 0.69); and TMAO, 0.33 (95% CI: 0.08, 0.58). No significant group differences were found for vitamin B-12, retinol, linoleic acid (LA), α-linolenic acid (ALA), or ratios of betaine to choline and LA to ALA.Conclusion: The findings supported our hypothesis that early introduction of eggs significantly improved choline and other markers in its methyl group metabolism pathway. This trial was registered at clinicaltrials.gov as NCT02446873.

Food allergy: Update on prevention and tolerance

Of the many possible hypotheses that explain the recent increase in childhood food allergy (FA), the dual-allergen exposure hypothesis has been the most extensively investigated. This chapter serves as a review and update on the prevention of FA and focuses on recently published randomized controlled trials exploring the efficacy of oral tolerance induction in infancy for the prevention of FA. As a result of these RCTs, National Institutes of Health recommendations now actively encourage the early introduction of peanut for the prevention of peanut allergy, and other countries/settings recommend the inclusion of potential common food allergens, including peanut and egg, in complementary feeding regimens commencing at approximately 6 months but not before 4 months of age. Further studies that explore the efficacy of oral tolerance induction to other common food allergens and that focus on optimal timing, duration, and adherence are required.

Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management

This review provides general information to serve as a primer for those embarking on understanding food allergy and also details advances and updates in epidemiology, pathogenesis, diagnosis, and treatment that have occurred over the 4 years since our last comprehensive review. Although firm prevalence data are lacking, there is a strong impression that food allergy has increased, and rates as high as approximately 10% have been documented. Genetic, epigenetic, and environmental risk factors are being elucidated increasingly, creating potential for improved prevention and treatment strategies targeted to those at risk. Insights on pathophysiology reveal a complex interplay of the epithelial barrier, mucosal and systemic immune response, route of exposure, and microbiome among other influences resulting in allergy or tolerance. The diagnosis of food allergy is largely reliant on medical history, tests for sensitization, and oral food challenges, but emerging use of component-resolved diagnostics is improving diagnostic accuracy. Additional novel diagnostics, such as basophil activation tests, determination of epitope binding, DNA methylation signatures, and bioinformatics approaches, will further change the landscape. A number of prevention strategies are under investigation, but early introduction of peanut has been advised as a public health measure based on existing data. Management remains largely based on allergen avoidance, but a panoply of promising treatment strategies are in phase 2 and 3 studies, providing immense hope that better treatment will be imminently and widely available, whereas numerous additional promising treatments are in the preclinical and clinical pipeline.

Introduction of various allergenic foods during infancy reduces risk of IgE sensitization at 12 months of age: a birth cohort study

BackgroundIn this study, we aimed to determine whether introducing various allergenic foods during infancy is associated with IgE sensitization at 12 months of age.MethodsDetailed information on feeding practices regarding six possible allergenic foods (fruits, egg white, egg yolk, fish, shellfish, and peanuts) was obtained by administering age-specific questionnaires to parents of infants at ages 6 and 12 months. Fecal secretory IgA (sIgA), fecal eosinophil cationic protein (ECP), and serum levels of total IgE and IgE specific to 20 foods, and IgE specific to 20 inhalant allergens were also quantified at 12 months of age.ResultsAt 12 months of age, infants with IgE sensitization had been introduced to fewer allergenic food items during infancy (3.2±1.4 vs. 3.7±1.3 items). Compared with infants who were given 0-2 allergenic food items, infants introduced to 3-4 or ≥5 allergenic food items showed a significantly lower risk of IgE sensitization (odds ratios (ORs) 0.62 and 0.61, respectively) and lower total IgE levels. In addition, non-introduction of egg white or egg yolk was significantly related to IgE sensitization (ORs 1.41 and 1.26, respectively).ConclusionIncreasing the diversity of allergenic foods in infancy, including fruits, egg white, egg yolk, fish, shellfish, and peanuts, may protect infants from IgE sensitization at 12 months of age.

Allergen specificity of early peanut consumption and effect on development of allergic disease in the Learning Early About Peanut Allergy study cohort

BACKGROUND

Early introduction of dietary peanut in high-risk infants with severe eczema, egg allergy, or both prevented peanut allergy at 5 years of age in the Learning Early About Peanut Allergy (LEAP) study. The protective effect persisted after 12 months of avoiding peanuts in the 12-month extension of the LEAP study (LEAP-On). It is unclear whether this benefit is allergen and allergic disease specific.

OBJECTIVE

We sought to assess the effect of early introduction of peanut on the development of allergic disease, food sensitization, and aeroallergen sensitization.

METHODS

Asthma, eczema, and rhinoconjunctivitis were diagnosed based on clinical assessment. Reported allergic reactions and consumption of tree nuts and sesame were recorded by questionnaire. Sensitization to food allergens and aeroallergens was determined by means of skin prick testing and specific IgE measurement.

RESULTS

A high and increasing burden of food allergen and aeroallergen sensitization and allergic disease was noted across study time points; 76% of LEAP participants had at least 1 allergic disease at 60 months of age. There were no differences in allergic disease between LEAP groups. There were small differences in sensitization and reported allergic reactions for select tree nuts, with levels being higher in the LEAP consumption group. Significant resolution of eczema and sensitization to egg and milk occurred in LEAP participants and was not affected by peanut consumption.

CONCLUSION

Early consumption of peanut in infants at high risk of peanut allergy is allergen specific and does not prevent the development of other allergic disease, sensitization to other food allergens and aeroallergens, or reported allergic reactions to tree nuts and sesame. Furthermore, peanut consumption does not hasten the resolution of eczema or egg allergy.

PLGA nanoparticles loaded with beta-lactoglobulin-derived peptides modulate mucosal immunity and may facilitate cow's milk allergy prevention

Beta-lactoglobulin (BLG)-derived peptides may facilitate oral tolerance to whey and prevent cow's milk allergy (CMA). Loading of BLG-peptides in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Pep-NP) may improve this. Here we studied the uptake of NP and the capacity of NP and Pep-NP to activate bone marrow dendritic cells (BMDC). Furthermore, CMA prevention was evaluated by orally exposing three-week-old female C3H/HeOuJ mice to Pep-NP, NP or free peptides (PepMix) for 6 days before oral sensitization with whole whey protein and effects on the spleen and small intestine lamina propria (SI-LP) were studied. In BMDC, NP and Pep-NP enhanced CD40 expression and IL-6 and TNF-α secretion, while tended to decrease CD80 expression and prevented PepMix-induced IL-12 secretion. In vivo, oral exposure to Pep-NP, but not NP or PepMix, prior to whey sensitization tended to partially prevent the acute allergic skin response to whole whey protein. Splenocytes of NP-pre-exposed mice secreted increased levels of whey-specific IL-6, but this was silenced in Pep-NP-pre-exposed mice which also showed reduced TNF-α and IFN-γ secretion. In the SI-LP, Pep-NP pre-exposure reduced the CD4⁺ T cell frequency in CMA mice compared to PBS pre-exposure. In addition, while NP increased whey-specific IL-6 secretion in the SI-LP, Pep-NP did not and maintained regulatory TGF-β secretion. This study presents a proof-of-concept that PLGA nanoparticles facilitate the capacity of BLG peptides to suppress the allergic response to whole whey protein. Hence, PLGA nanoparticles may be further developed as an adjunct strategy for BLG-peptide-based oral tolerance induction and CMA prevention.

Dietary Intervention with β-Lactoglobulin-Derived Peptides and a Specific Mixture of Fructo-Oligosaccharides and Bifidobacterium breve M-16V Facilitates the Prevention of Whey-Induced Allergy in Mice by Supporting a Tolerance-Prone Immune Environment

Cow's milk allergy (CMA) prevails in infants and brings increased risk of developing other allergic diseases. Oral administration of specific β-lactoglobulin (BLG)-derived peptides (PepMix) and a specific blend of short- and long-chain fructo-oligosaccharides and Bifidobacterium breve M-16V (FF/Bb) was found to partially prevent CMA development in mice. In this study, we aimed to expand the knowledge on the preventive potential and the underlying mechanisms of this approach. Three-week-old female C3H/HeOuJ mice were orally exposed to PepMix±FF/Bb prior to a 5-week oral sensitization with whole whey and cholera toxin as an adjuvant. The acute allergic skin response was determined after an intradermal challenge with whole whey protein. Following an oral challenge with whey, regulatory T cells (T_regs) in the small intestine lamina propria (SI-LP) and mRNA expression of immune markers in the Peyer's patches (PP) were investigated. The early impact of PepMix and FF/Bb interventions on the immune system during the oral tolerance (OT) induction phase was investigated after the last OT administration. Pre-exposing mice to PepMix+FF/Bb partially prevented the acute allergic skin response compared to PBS and increased T_regs and activated T cells in the SI-LP compared to sham-sensitized mice. It also increased the mRNA expression of Tbet over GATA3 in the PP of whey-sensitized mice. Directly upon the 6-day OT phase, FF/Bb intervention enhanced cecal content levels of propionic and butyric acid in PepMix-fed mice and the former was positively correlated with Foxp3⁺ cell numbers in the colon. In the PP of PepMix+FF/Bb-exposed mice, IL-22 mRNA expression increased and IL-10 followed the same tendency, while the Foxp3 expression was increased over GATA3 and RorγT. In the colon, the Tbet mRNA expression increased over GATA3, while IL-22 decreased. In addition, the Foxp3⁺/GATA3⁺ and regulatory/effector T cell ratios in the mesenteric lymph nodes and the CD11b⁺/CD11b^- conventional dendritic cells ratio in the SI-LP were increased. In conclusion, the FF/Bb diet facilitates the capacity of the specific BLG-peptides to partially prevent the allergic response after sensitization to whole whey protein, possibly by creating a tolerance-prone environment during the OT phase. Such a dietary intervention might contribute to tailoring successful strategies for CMA prevention.

Timing of food introduction and development of food sensitization in a prospective birth cohort

BACKGROUND

The effect of infant feeding practices on the development of food allergy remains controversial. We examined the relationship between timing and patterns of food introduction and sensitization to foods at age 1 year in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study.

METHODS

Nutrition questionnaire data prospectively collected at age 3, 6, 12, 18, and 24 months were used to determine timing of introduction of cow's milk products, egg, and peanut. At age 1 year, infants underwent skin prick testing to cow's milk, egg white, and peanut. Logistic regression models were fitted to assess the impact of timing of food exposures on sensitization outcomes, and latent class analysis was used to study patterns of food introduction within the cohort.

RESULTS

Among 2124 children with sufficient data, delaying introduction of cow's milk products, egg, and peanut beyond the first year of life significantly increased the odds of sensitization to that food (cow's milk adjOR 3.69, 95% CI 1.37-9.08; egg adjOR 1.89, 95% CI 1.25-2.80; peanut adjOR 1.76, 95% CI 1.07-3.01). Latent class analysis produced a three-class model: early, usual, and delayed introduction. A pattern of delayed introduction, characterized by avoidance of egg and peanut during the first year of life, increased the odds of sensitization to any of the three tested foods (adjOR 1.78, 95% CI 1.26-2.49).

CONCLUSIONS

Avoidance of potentially allergenic foods during the first year of life significantly increased the odds of sensitization to the corresponding foods.

Low Food Allergy Prevalence Despite Delayed Introduction of Allergenic Foods-Data from the GUSTO Cohort

BACKGROUND

There is mounting evidence that early introduction of allergenic food decreases the risk of food allergy development, especially in high-risk infants with eczema. However, there is a lack of data to suggest whether this association holds true in Asian populations.

OBJECTIVE

To investigate the relationship between the timing of introduction of allergenic foods and food allergy outcomes in infants in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study.

METHODS

The GUSTO cohort recruited 1152 mothers of Chinese, Malay, and Indian ethnicity who had singleton, naturally conceived pregnancies and followed their offspring prospectively. Information on demographic characteristics, child health, infant feeding practices, and a convincing history of IgE-mediated food allergy was obtained from interviewer-administered questionnaires at multiple time points. Corroborative skin prick tests to food allergens were performed at 18 and 36 months.

RESULTS

Most of the infants were introduced to egg (49.6%), peanut (88.7%), and shellfish (90.2%) after age 10 months. Food allergy prevalence was, however, very low between age 12 and 48 months: egg, 0.35% to 1.8%; peanut allergy, 0.1% to 0.3%; and shellfish, 0.2% to 0.9%. There were no significant associations between the timing of introduction of allergenic foods and the development of food allergy, adjusted for confounders including breast-feeding and eczema.

CONCLUSIONS

Food allergy rates in Singapore are low despite delayed introduction of allergenic foods. Early introduction of allergenic foods may thus not be necessary in populations in which overall food allergy prevalence is low, and thus infant feeding recommendations should be carefully tailored to individual populations.