Fish consumption during the first year of life and development of allergic diseases during childhood

The role of dietary interventions in the prevention of IgE-mediated food allergy in children

Over the last 30 years, the prevalence of food allergy has been on the rise and remains a disease that can have a significant impact on the quality of life of children and their families. There are several hypotheses that have been suggested to account for the increasing prevalence, but this review will focus on the impact that dietary factors have on food allergy development. In the past food allergy, prevalence has largely focused on allergen avoidance; however, there is increasing evidence from interventional studies that have shown that early introduction to potential food allergens may have a beneficial role in allergy prevention. This review aims to look at the evidence in support of early introduction of allergens into infant diets to prevent against the development of food allergy.

Relationship Between Plant Food (Fruits, Vegetables, and Kimchi) Consumption and the Prevalence of Rhinitis Among Korean Adults: Based on the 2011 and 2012 Korea National Health and Nutrition Examination Survey Data

The aim of the current study was to analyze the relationship between plant food (fruits, vegetables, and kimchi) and the prevalence of rhinitis among Korean adults using data from the 2011 and 2012 Korea National Health and Nutrition Examination Survey. A total of 7494 subjects aged from 19 to 64 years participated in a rhinitis morbidity survey, health behavior interview, and 24-h dietary recall test. Individuals with energy intakes less than 500 kcal or more than 5000 kcal were excluded. The results showed that kimchi intake was inversely associated with the prevalence of rhinitis. The prevalence of rhinitis decreased with increasing kimchi consumption. The quintile 4 (range of kimchi intake: 108.0-180.0 g) groups, compared with the reference of quintile 1 (0-23.7 g), showed a decrease of 18.9% (odds ratio [OR] = 0.811, 95% confidence interval [CI] = 0.672-0.979) in Model 4. In conclusion, consumption of kimchi lowers the risk of rhinitis, suggesting that its use should be encouraged among the Korean population.

Fish intake during pregnancy or infancy and allergic outcomes in children: A systematic review and meta-analysis

It has been suggested that n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) have anti-inflammatory properties and may reduce the risk of allergic disease. Fish is a great source of n-3 LC-PUFAs. However, the effect of fish on allergic disease remains controversial. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) and prospective cohort studies regarding the effect of fish intake during pregnancy or infancy on allergic outcomes in children. The outcomes of interest were atopy, eczema, allergic rhinitis, wheeze, asthma, and food allergy. One RCT and 17 publications from 13 prospective cohort studies were included for maternal fish intake during pregnancy, and eight publications from five prospective cohort studies for fish intake in infancy. Pooled analysis suggested that maternal fish intake during pregnancy was not associated with lower risk of any allergic outcome, both in RCT and observational studies. Consumption of fish during the first year of life reduced the risk of eczema (RR 0.61; 95% CI 0.47, 0.80; p = 0.0003; I²  = 68%) and allergic rhinitis (RR 0.54; 95% CI 0.36, 0.81; p = 0.003; I²  = 74%). Current evidence indicates that fish intake in infancy could reduce the risk of eczema and allergic rhinitis in children, whereas maternal fish intake during pregnancy does not affect any atopic outcome. The intake of fish per se in infancy, not specially n-3 LC-PUFAs, may have an allergy protective effect. High-quality and adequately powered RCTs are warranted to confirm this.

Allergenicity of bony and cartilaginous fish - molecular and immunological properties

Allergy to bony fish is common and probably increasing world-wide. The major heat-stable pan-fish allergen, parvalbumin (PV), has been identified and characterized for numerous fish species. In contrast, there are very few reports of allergic reactions to cartilaginous fish despite widespread consumption. The molecular basis for this seemingly low clinical cross-reactivity between these two fish groups has not been elucidated. PV consists of two distinct protein lineages, α and β. The α-lineage of this protein is predominant in muscle tissue of cartilaginous fish (Chondrichthyes), while β-PV is abundant in muscle tissue of bony fish (Osteichthyes). The low incidence of allergic reactions to ingested rays and sharks is likely due to the lack of molecular similarity, resulting in reduced immunological cross-reactivity between the two PV lineages. Structurally and physiologically, both protein lineages are very similar; however, the amino acid homology is very low with 47-54%. Furthermore, PV from ancient fish species such as the coelacanth demonstrates 62% sequence homology to leopard shark α-PV and 70% to carp β-PV. This indicates the extent of conservation of the PV isoforms lineages across millennia. This review highlights prevalence data on fish allergy and sensitization to fish, and details the molecular diversity of the two protein lineages of the major fish allergen PV among different fish groups, emphasizing the immunological and clinical differences in allergenicity.

Modifying the infant's diet to prevent food allergy

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

Two-step egg introduction for prevention of egg allergy in high-risk infants with eczema (PETIT): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Evidence is accumulating that early consumption is more beneficial than is delayed introduction as a strategy for primary prevention of food allergy. However, allergic reactions caused by early introduction of such solid foods have been a problematic issue. We investigated whether or not early stepwise introduction of eggs to infants with eczema combined with optimal eczema treatment would prevent egg allergy at 1 year of age.

METHODS

In this randomised, double-blind, placebo-controlled trial, we enrolled infants 4-5 months of age with eczema from two centres in Japan. Exclusion criteria were being born before 37 weeks of gestational age, experience of ingestion of hen's eggs or egg products, history of immediate allergic reaction to hen's eggs, history of non-immediate allergic reaction to a particular type of food, and complications of any severe disease. Infants were randomly assigned (block size of four; stratified by institution and sex) to early introduction of egg or placebo (1:1). Participants in the egg group consumed orally 50 mg of heated egg powder per day from 6 months to 9 months of age and 250 mg per day thereafter until 12 months of age. We aggressively treated participants' eczema at entry and maintained control without exacerbations throughout the intervention period. Participants and physicians were masked to assignment, and allocation was concealed. The primary outcome was the proportion of participants with hen's egg allergy confirmed by open oral food challenges at 12 months of age, assessed blindly by standardised methods, in all randomly allocated participants who received the intervention. This trial is registered with the University Hospital Medical Information Network Clinical Trials Registry, number UMIN000008673.

FINDINGS

Between Sept 18, 2012, and Feb 13, 2015, we randomly allocated 147 participants (73 [50%] to the egg group and 74 [50%] to the placebo group). This trial was terminated on the basis of the results of the scheduled interim analysis of 100 participants, which showed a significant difference between the two groups (four [9%] of 47 participants had an egg allergy in the egg group vs 18 [38%] of 47 in the placebo group; risk ratio 0·222 [95% CI 0·081-0·607]; p=0·0012). In the primary analysis population, five (8%) of 60 participants had an egg allergy in the egg group compared with 23 (38%) of 61 in the placebo group (risk ratio 0·221 [0·090-0·543]; p=0·0001). The only difference in adverse events between groups was admissions to hospital (six [10%] of 60 in the egg group vs none in the placebo group; p=0·022). 19 acute events occurred in nine (15%) participants in the egg group versus 14 events in 11 (18%) participants in the placebo group after intake of the trial powder.

INTERPRETATION

Introduction of heated egg in a stepwise manner along with aggressive eczema treatment is a safe and efficacious way to prevent hen's egg allergy in high-risk infants. In this study, we developed a practical approach to overcome the second wave of the allergic epidemic caused by food allergy.

FUNDING

Ministry of Health, Labour and Welfare, and National Centre for Child Health and Development, Japan.

High levels of omega-3 fatty acids in milk from omega-3 fatty acid-supplemented mothers are related to less immunoglobulin E-associated disease in infancy

AIM

We previously reported a protective effect of maternal omega-3 fatty acid supplements on the development of immunoglobulin E (IgE)-associated disease in infancy. This study assessed omega-3 long-chain polyunsaturated fatty acids (LCPUFA) in maternal milk in relation to omega-3 LCPUFA supplementation and the development of allergic disease in their infants.

METHODS

This study randomised 95 pregnant women at risk of having an allergic infant, to daily supplements of 2.6 g omega-3 LCPUFA or a placebo of 2.7 g soya bean oil from gestational week 25 until 3 months of lactation. Breast milk samples were collected as colostrum, at one and 3 months. Milk fatty acids were related to allergic outcome in the infants at 24 months.

RESULTS

Omega-3 milk fatty acids were higher in women who received omega-3 supplements than the placebo group (p < 0.01). Higher proportions of milk eicosapentaenoic acid and docosahexaenoic acid and a lower arachidonic/eicosapentaenoic acid ratio were associated with an absence of IgE-associated disease in the infants. None of the children developed IgE-associated atopic eczema above a level of 0.83 mol% eicosapentaenoic acid in colostrum. [Correction added on 7 July 2016, after online publication: In the preceding sentence, the correct word should be "above" instead of "below" and this has been amended in this current version.] CONCLUSION: High omega-3 LCPUFA milk levels in mothers who received omega-3 LCPUFA supplements were related to fewer allergies in their children.

Polyunsaturated fatty acid supplementation in infancy for the prevention of allergy

BACKGROUND

Early dietary intakes may influence the development of allergic disease. It is important to determine if dietary polyunsaturated fatty acids (PUFAs) given as supplements or added to infant formula prevent the development of allergy.

OBJECTIVES

To determine the effect of higher PUFA intake during infancy to prevent allergic disease.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 9), MEDLINE (1966 to 14 September 2015), EMBASE (1980 to 14 September 2015) and CINAHL (1982 to 14 September 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared the use of a PUFA with no PUFA in infants for the prevention of allergy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data from the included studies. We used fixed-effect analyses. The treatment effects were expressed as risk ratio (RR) with 95% confidence intervals (CI). We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

The search found 17 studies that assessed the effect of higher versus lower intake of PUFAs on allergic outcomes in infants. Only nine studies enrolling 2704 infants reported allergy outcomes that could be used in meta-analyses. Of these, there were methodological concerns for eight.In infants up to two years of age, meta-analyses found no difference in incidence of all allergy (1 study, 323 infants; RR 0.96, 95% CI 0.73 to 1.26; risk difference (RD) -0.02, 95% CI -0.12 to 0.09; heterogeneity not applicable), asthma (3 studies, 1162 infants; RR 1.04, 95% CI 0.80 to 1.35, I2 = 0%; RD 0.01, 95% CI -0.04 to 0.05, I2 = 0%), dermatitis/eczema (7 studies, 1906 infants; RR 0.93, 95% CI 0.82 to 1.06, I2 = 0%; RD -0.02, 95% CI -0.06 to 0.02, I2 = 0%) or food allergy (3 studies, 915 infants; RR 0.81, 95% CI 0.56 to 1.19, I2 = 63%; RD -0.02, 95% CI -0.06 to 0.02, I2 = 74%). There was a reduction in allergic rhinitis (2 studies, 594 infants; RR 0.47, 95% CI 0.23 to 0.96, I2 = 6%; RD -0.04, 95% CI -0.08 to -0.00, I2 = 54%; number needed to treat for an additional beneficial outcome (NNTB) 25, 95% CI 13 to ∞).In children aged two to five years, meta-analysis found no difference in incidence of all allergic disease (2 studies, 154 infants; RR 0.69, 95% CI 0.47 to 1.02, I2 = 43%; RD -0.16, 95% CI -0.31 to -0.00, I2 = 63%; NNTB 6, 95% CI 3 to ∞), asthma (1 study, 89 infants; RR 0.45, 95% CI 0.20 to 1.02; RD -0.20, 95% CI -0.37 to -0.02; heterogeneity not applicable; NNTB 5, 95% CI 3 to 50), dermatitis/eczema (2 studies, 154 infants; RR 0.65, 95% CI 0.34 to 1.24, I2 = 0%; RD -0.09 95% CI -0.22 to 0.04, I2 = 24%) or food allergy (1 study, 65 infants; RR 2.27, 95% CI 0.25 to 20.68; RD 0.05, 95% CI -0.07 to 0.16; heterogeneity not applicable).In children aged two to five years, meta-analysis found no difference in prevalence of all allergic disease (2 studies, 633 infants; RR 0.98, 95% CI 0.81 to 1.19, I2 = 36%; RD -0.01, 95% CI -0.08 to 0.07, I2 = 0%), asthma (2 studies, 635 infants; RR 1.12, 95% CI 0.82 to 1.53, I2 = 0%; RD 0.02, 95% CI -0.04 to 0.09, I2 = 0%), dermatitis/eczema (2 studies, 635 infants; RR 0.81, 95% CI 0.59 to 1.09, I2 = 0%; RD -0.04 95% CI -0.11 to 0.02, I2 = 0%), allergic rhinitis (2 studies, 635 infants; RR 1.02, 95% CI 0.83 to 1.25, I2 = 0%; RD 0.01, 95% CI -0.06 to 0.08, I2 = 0%) or food allergy (1 study, 119 infants; RR 0.27, 95% CI 0.06 to 1.19; RD -0.10, 95% CI -0.20 to -0.00; heterogeneity not applicable; NNTB 10, 95% CI 5 to ∞).

AUTHORS' CONCLUSIONS

There is no evidence that PUFA supplementation in infancy has an effect on infant or childhood allergy, asthma, dermatitis/eczema or food allergy. However, the quality of evidence was very low. There was insufficient evidence to determine an effect on allergic rhinitis.

Prevention of food allergy - Early dietary interventions

The prevalence of food allergy has increased over the last 30 years and remains a disease, which significantly impacts on the quality of life of children and their families. Several hypotheses have been formulated to explain the increasing prevalence; this review will focus on the hypothesis that dietary factors may influence the development of food allergy. Historically, the prevention of food allergy has focused on allergen avoidance. However, recent findings from interventional studies have prompted a shift in the mind set from avoidance to early introduction of potentially allergenic foods. This review aims to facilitate a better understanding of contemporary research studies that make use of early introduction of common allergenic foods into infant diets as a preventative strategy against the development of food allergy.

Allergic sensitisation in early childhood: Patterns and related factors in PARIS birth cohort

BACKGROUND

Allergic sensitisation is poorly documented in infants. This study aims to provide new insights into allergic sensitisation patterns and related factors in infancy.

METHODS

This study concerns 1860 infants involved in the Pollution and Asthma Risk: an Infant Study (PARIS) population-based birth cohort who had a standardised health examination when 18 months old, from 2004 to 2008. Sensitisation was assessed by measurements of serum specific IgE to 12 food and 4 inhalant allergens and defined by IgE≥0.35kU_A/L. Information regarding lifestyle and environment were obtained from questionnaires prospectively administered.

RESULTS

Prevalence of allergic sensitisation to any allergen, to food allergens, and to aeroallergens was 13.8%, 12.3%, and 2.3%, respectively. Multiple sensitisation (to at least two allergens) concerned 6.2% of toddlers. Intrinsic factors such as male gender, family history of allergy, and high birth weight increased the risk of food allergen sensitisation and multiple sensitisation. Caesarean section was also positively associated with multiple sensitisation. Day-care attendance was negatively related to food allergen, aeroallergen, and multiple sensitisation. A cat entering the baby's room in early life was strongly associated with aeroallergen sensitisation (ORa 3.21, 95%CI: 1.29-8.01). An introduction of meat in infant's diet after 6 months of age was negatively related to food allergen sensitisation (ORa 0.46, 95%CI: 0.24-0.91).

CONCLUSION

Our results suggest that intrinsic factors and indicators of exposure to microorganisms such as caesarean section and day-care attendance may be associated with inhalant as well as food allergen sensitisation in infancy. For example, male gender, family history of allergy, high birth weight, and caesarean section could be positively related whereas day-care attendance could be negatively related to both aeroallergen and food allergen sensitisation. Conversely, early life exposure to inhalant allergens or food allergens may be specifically linked to either aeroallergen sensitisation or food allergen sensitisation, respectively.

Prevention of food allergy

The past few decades have witnessed an increase in the prevalence of IgE-mediated food allergy (FA). For prevention strategies to be effective, we need to understand the causative factors underpinning this rise. Genetic factors are clearly important in the development of FA, but given the dramatic increase in prevalence over a short period of human evolution, it is unlikely that FA arises through germline genetic changes alone. A plausible hypothesis is that 1 or more environmental exposures, or lack thereof, induce epigenetic changes that result in interruption of the default immunologic state of tolerance. Strategies for the prevention of FA might include primary prevention, which seeks to prevent the onset of IgE sensitization; secondary prevention, which seeks to interrupt the development of FA in IgE-sensitized children; and tertiary prevention, which seeks to reduce the expression of end-organ allergic disease in children with established FA. This review emphasizes the prevention of IgE-mediated FA through dietary manipulation, among other strategies; in particular, we focus on recent interventional studies in this field.

Randomized controlled trial of early regular egg intake to prevent egg allergy

BACKGROUND

The ideal age to introduce egg into the infant diet has been debated for the past 2 decades in the context of rising rates of egg allergy.

OBJECTIVE

We sought to determine whether regular consumption of egg protein from age 4 to 6 months reduces the risk of IgE-mediated egg allergy in infants with hereditary risk, but without eczema.

METHODS

Infants aged 4 to 6 months were randomly allocated to receive daily pasteurized raw whole egg powder (n = 407) or a color-matched rice powder (n = 413) to age 10 months. All infants followed an egg-free diet and cooked egg was introduced to both groups at age 10 months. The primary outcome was IgE-mediated egg allergy defined by a positive pasteurized raw egg challenge and egg sensitization at age 12 months.

RESULTS

There was no difference between groups in the percentage of infants with IgE-mediated egg allergy (egg 7.0% vs control 10.3%; adjusted relative risk, 0.75; 95% CI, 0.48-1.17; P = .20). A higher proportion of participants in the egg group stopped taking the study powder because of a confirmed allergic reaction (25 of 407 [6.1%] compared with 6 of 413 [1.5%]). Egg-specific IgG₄ levels were substantially higher in the egg group at 12 months (median, 1.22 mg_A/L vs control 0.07 mg_A/L; P < .0001).

CONCLUSIONS

We found no evidence that regular egg intake from age 4 to 6 months substantially alters the risk of egg allergy by age 1 year in infants who are at hereditary risk of allergic disease and had no eczema symptoms at study entry.

Persistence of atopic dermatitis (AD): A systematic review and meta-analysis

BACKGROUND

Previous studies found conflicting results about whether childhood atopic dermatitis (AD) persists into adulthood.

OBJECTIVE

We sought to determine persistence rates and clinical factors associated with prolonged AD.

METHODS

A systematic review was performed in MEDLINE, EMBASE, Scopus, GREAT, LILACS, Web of Science, Academic Search Complete, and Cochrane Library. Meta-analysis was performed using Kaplan-Meier plots and random-effects proportional hazards regression.

RESULTS

In total, 45 studies including 110,651 subjects spanning 434,992 patient-years from 15 countries were included. In pooled analysis, 80% of childhood AD did not persist by 8 years and less than 5% persisted by 20 years after diagnosis (mean ± SE: 6.1 ± 0.02 years). Children with AD that persisted already for more than 10 years (8.3 ± 0.08 years) had longer persistence than those with 3 (3.2 ± 0.02 years) or 5 (6.8 ± 0.06 years) years of persistence. Children who developed AD by age 2 years had less persistent disease (P < .0001). Persistence was greater in studies using patient-/caregiver-assessed versus physician-assessed outcomes, female versus male patients (P ≤ .0006), but not in those with sensitivity to allergens (P = .90). Three studies found prolonged persistence with more severe AD.

LIMITATIONS

Some studies did not capture recurrences later in life.

CONCLUSIONS

Most childhood AD remitted by adulthood. However, children with already persistent disease, later onset, and/or more severe disease have increased persistence.

Timing of eczema onset and risk of food allergy at 3 years of age: A hospital-based prospective birth cohort study

BACKGROUND

Although recent studies suggest that eczema in early childhood is important in the development of food allergy, the importance of the timing of eczema onset has not been fully clarified.

OBJECTIVE

This study aim to identify an association between the timing of eczema onset and development of food allergy in a prospective birth cohort study.

METHODS

Data were obtained from the Tokyo Children's Health, Illness and Development (T-CHILD) study, which is a hospital-based birth cohort study currently in progress in Japan. A total of 1550 children were born to the recruited women. Outcome data for children were collected from questionnaires completed at 6 months, 1 and 3 years of age. Association between the timing of eczema onset and development of food allergy was estimated by logistic regression analyses. All analysis were performed using SPSS software with a two-sided 5% significance level.

RESULTS

Eczema in the first year of life was a significant risk factor in multivariate analysis (aOR 3.90, 95% CI 2.34-6.52, p<0.001). In each age (by month) stratum, infants with onset of eczema within the first 1-2 months after birth had the highest risk of food allergy at 3 years of age (aOR 6.61, 95% CI 3.27-13.34, p<0.001).

CONCLUSION

Infants with early eczema onset (especially within the first 1-4 months after birth) were found to have an increased risk of developing food allergy at 3 years of age. Our findings may contribute to a better understanding of the timing of eczema onset as a potentially modifiable risk factor and to defining those who may need to be on guard for food allergy.

Breastfeeding and Complementary Feeding

BACKGROUND

Proper infant nutrition promotes healthy growth and development and lowers the risk of disease in later life.

METHODS

This review is based on pertinent articles retrieved by a selective search, including guidelines, meta-analyses, and systematic reviews.

RESULTS

Infants should be exclusively breast-fed until at least the age of 4 months. Infants who are no longer being breast-fed, or no longer exclusively so, should be given commercially available low-protein infant formula containing long-chain polyunsaturated fatty acids. Infants with a family history of allergy should be fed with infant formula based on hydrolyzed protein until complementary feeding begins. Complementary feeding should be initiated no earlier than the beginning of the 5th month and no later than the beginning of the 7th; it should include iron derived from meat, as well as fish once or twice a week. Later initiation of complementary feeding is associated with an increased risk of allergies and is not recommended. Ordinary cow's milk should not be drunk in the first year of life. All infants should be given 2 mg of vitamin K at birth, at 7-10 days, and at 4-6 weeks of age, as well as daily oral supplementation of vitamin D (400-500 IE) and fluoride (0.25 mg).

CONCLUSION

Physicians should advise families about healthful infant nutrition in order to lay the foundation for lifelong good health through a proper diet.

Update on Early Nutrition and Food Allergy in Children

With growing evidence of an increase in the prevalence, food allergy has been emerged as a new public health problem. As treatment and management of food allergy remain challenging, more attention has been paid to the importance of prevention of food allergy. Although the exact mechanism of recent epidemic is not fully understood, it is suggested that nutritional exposure in early life may play an important role in food allergy development. The underlying hypothesis is that nutritional status or food exposure in the critical period of fetal development can affect the programming of immune system and modify the risk of immunologic reactions to foods in postnatal life. We review accumulating epidemiological studies to examine an association between nutritional exposure during pregnancy or early infancy and food allergy development in children. We also discuss recent advances in the studies of the genetic and epigenetic regulation of food allergy and evaluate the role of early nutrition in food allergy development to provide a new perspective on the prevention of food allergy.

The rise of food allergy: Environmental factors and emerging treatments

Food allergy has rapidly increased in prevalence, suggesting an important role for environmental factors in disease susceptibility. The immune response of food allergy is characterized by IgE production, and new findings from mouse and human studies indicate an important role of the cytokine IL-9, which is derived from both T cells and mast cells, in disease manifestations. Emerging evidence suggests that route of exposure to food, particularly peanut, is important. Exposure through the skin promotes sensitization while early exposure through the gastrointestinal tract promotes tolerance. Evidence from mouse studies indicate a role of the microbiome in development of food allergy, which is supported by correlative human studies showing a dysbiosis in food allergy. There is no approved treatment for food allergy, but emerging therapies are focused on allergen immunotherapy to provide desensitization, while pre-clinical studies are focused on using adjuvants or novel delivery approaches to improve efficacy and safety of immunotherapy.

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Emerging evidence suggests that route of exposure to food allergens in early life determines sensitization versus tolerance.

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The microbiota and dietary factors appear to play a key role in susceptibility to food allergy.

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Immunotherapy applied via different routes is currently the most promising form of experimental treatment for food allergy.

Exploring the Effects of Omega-3 and Omega-6 Fatty Acids on Allergy Using a HEK-Blue Cell Line

BACKGROUND

Allergic reactions can result in life-threatening situations resulting in high economic costs and morbidity. Therefore, more effective reagents are needed for allergy treatment. A causal relationship has been suggested to exist between the intake of omega-3/6 fatty acids, such as docosahexanoic acid (DHA), eicosapentanoic acid (EPA), docosapentanoic acid (DPA) and arachidonic acid (AA), and atopic individuals suffering from allergies. In allergic cascades, the hallmark cytokine IL-4 bind to IL-4 receptor (IL-4R) and IL-13 binds to IL-13 receptor (IL-13R), this activates the STAT6 phosphorylation pathway leading to gene activation of allergen-specific IgE antibody production by B cells. The overall aim of this study was to characterize omega-3/6 fatty acids and their effects on STAT6 signaling pathway that results in IgE production in allergic individuals.

METHODS

The fatty acids were tested in vitro with a HEK-Blue IL-4/IL-13 reporter cell line model, transfected with a reporter gene that produces an enzyme, secreted embryonic alkaline phosphatase (SEAP). SEAP acts as a substitute to IgE when cells are stimulated with bioactive cytokines IL-4 and/or IL-13.

RESULTS

We have successfully used DHA, EPA and DPA in our studies that demonstrated a decrease in SEAP secretion, as opposed to an increase in SEAP secretion with AA treatment. A statistical Student's t-test revealed the significance of the results, confirming our initial hypothesis.

CONCLUSION

We have successfully identified and characterised DHA, EPA, DPA and AA in our allergy model. While AA was a potent stimulator, DHA, EPA and DPA were potential inhibitors of IL-4R/IL-13R signalling, which regulates the STAT6 induced pathway in allergic cascades. Such findings are significant in the future design of dietary therapeutics for the treatment of allergies.

Fat intake and breast milk fatty acid composition in farming and nonfarming women and allergy development in the offspring

BACKGROUND

Children growing up on small family farms are at much lower risk of developing allergy than other children. We hypothesized that low intake of margarine and polyunsaturated fats among farming families could contribute to this protection.

METHODS

Twenty-eight mother-infant pairs living on small dairy farms and 37 nonfarm rural resident pairs were recruited in the FARMFLORA birth cohort. Food items expected to affect dietary fat composition were recorded by food frequency questionnaires during pregnancy and by 24-h recalls followed by 24-h food diaries during lactation. Allergy was diagnosed by doctors, using strict predefined criteria. Maternal diet and breast milk fat composition were compared between farming and nonfarming mothers and related to children's allergy at age 3 y.

RESULTS

Farming mothers consumed more butter, whole milk, saturated fat, and total fat than nonfarming mothers, who consumed more margarine, oils, and low-fat milk. Farming mothers' breast milk contained higher proportions of saturated and lower proportions of polyunsaturated fat. Allergy was eight times more common in nonfarm children. Mothers of allergic children consumed more margarine and oils than mothers of nonallergic children.

CONCLUSION

Low maternal consumption of margarine and vegetable oils might contribute to the allergy-preventive effect of growing up on small dairy farms.

Taking the leap earlier: the timing of tolerance

PURPOSE OF REVIEW

The paradigm for the primary prevention of peanut allergy was, until recently, strict avoidance of peanut during pregnancy, infancy, and early childhood. However, in countries that had these dietary guidelines, the prevalence of peanut allergy greatly increased in contrast to low prevalence rates of peanut allergy in countries where infant diets included peanut at an early age, suggesting the hypothesis that early introduction of peanut is superior to delayed introduction of peanut as a strategy for the primary prevention of food allergy. This review examines recent high-quality studies that support this hypothesis.

RECENT FINDINGS

Publication of the Learning Early about Allergy to Peanut interventional trial showed that 17% of children avoiding peanut until 5 years of age developed peanut allergy compared with 3% of children who started eating peanut at ages of 4-11 months. Two birth cohort studies demonstrated that high maternal consumption of peanut during the pregnancy period reduced the risk of peanut allergy in offspring by 50-75%.

SUMMARY

Recent studies indicate that early introduction of peanut enhances the development of tolerance to peanut, reducing the risk of childhood peanut allergy.

Omega-3 Fatty Acids Supplementation in Children to Prevent Asthma: Is It Worthy?-A Systematic Review and Meta-Analysis

Asthma is one of the most common respiratory diseases affecting all age groups. The world is now trying to identify some dietary factors which can play a preventive role. We performed this systematic review and meta-analysis of RCTs to assess the effect of intake of polyunsaturated fatty acid (PUFA) in infancy and/or childhood on incidence of asthma or wheezing episodes. We searched MEDLINE, EBSCO, Trip, and Google Scholar up to January 31, 2015. All RCTs where infants or children who were given omega-3 fatty acid supplementation and which reported incidence of asthma and/or wheezing episodes as dichotomous outcomes were included in this review. Random effects model was used for pooling the risk estimates. Total five articles were included. Most of them were from Australia. On meta-analysis, the pooled estimate of odds ratios by random effects model showed no significant change in incidence of asthma after supplementation of omega-3 FA in infancy or childhood (OR 0.974; CI 0.646, 1.469; p = 0.900). We concluded that a multicentric RCT is required to assess the effect of omega-3 FA supplementation exclusively to infants or children to predict the best time of omega-3 FA supplementation to prevent asthmatic or wheezing episodes later in life.

The role of epigenetic mediation and the future of food allergy research

IgE-mediated food allergy is a developing global health problem with prevalence rising at alarmingly fast rates. In this review, we discuss the interplay between genetics, epigenetics, and environmental exposures in the pathogenesis of food allergies. We aim to highlight the most recent evidence that suggests how epigenetic control may mediate genetic susceptibility of food allergies. We also examine how epigenetic modifications may be the key in explaining how environmental factors modulate and modify gene expression, leading to the dysregulation of immune tolerance and consequently, the development of food allergies. The emerging epigenetic paradigm in food allergies is likely to provide new mechanistic insight into food allergy risk and development as well as shape our therapeutic and preventive strategies.

The impact of diet on asthma and allergic diseases

The incidence of allergic diseases is increasing, both in developed and developing countries, concomitantly with the rise in living standards and the adoption of a 'western lifestyle'. For two decades, the hygiene hypothesis - which proposes that the lack of early childhood exposure to infectious agents increases susceptibility to allergic diseases in later life - provided the conceptual framework for unravelling the mechanisms that could account for the increased incidence of allergic diseases. In this Review, we discuss recent evidence that highlights the role of diet as a key factor influencing immune homeostasis and the development of allergic diseases through a complex interplay between nutrients, their metabolites and immune cell populations. Although further investigations are still required to understand these complex relationships, recent data have established a possible connection between metabolic homeostasis and allergic diseases.

Food allergy in Singapore: opening a new chapter

With the exception of shellfish, the overall food allergy rates in Singapore have not reached the epidemic proportions of the West. The rates of egg, milk and fish allergies remain low. However, the patterns of some food allergies in Singapore have changed over the last decade. For example, peanut allergy, once rare in Singapore, is now the most common cause of anaphylaxis in children. Studies analysing lifestyle practices, particularly with respect to prevention of food allergy, are necessary in order for practitioners to understand global differences and maintain this low prevalence.

Clinical manifestation and sensitization of allergic children from Malaysia

BACKGROUND

An epidemiological rise of allergic diseases in developing countries raises new challenges. Currently a paucity of data exists describing allergy symptomology and sensitization to common food and aeroallergens in young children from developing countries.

OBJECTIVE

To compare changes in symptomology, food allergen sensitization and aeroallergen sensitization in a cross-sectional study of children <2 years and 2-10 years.

METHODS

A total of 192 allergic children (aged <2 years, 35 children; aged 2-10 years, 157 children) underwent specific IgE (>0.35 kU/L) to common food (egg white, cow's milk, cod fish, wheat, peanut, soya, peanut, and shrimp) and house dust mites (Dermatophagoides pteronyssinus and Blomia tropicalis).

RESULTS

In children <2 years, atopic dermatitis (65.7%) was the most common symptom whereas in children 2-10 years it was rhinoconjunctivitis (74.5%). Higher sensitization rate to eggs (p < 0.01) and cow's milk (p = 0.044) was seen in <2 years group when compared to the 2-10 years group, but no significant differences for shrimp (p = 0.29), wheat (p = 0.23) and soya (p = 0.057). Interestingly, sensitization to peanut (p = 0.012) and fish (p = 0.035) was significantly decreased in the 2-10 years group. Sensitization to house dust mites (p < 0.01) dramatically increased in the older children.

CONCLUSION

Our study supports concept of atopic march from a developing country like Malaysia.

Update on epigenetics in allergic disease

Chronic inflammatory diseases, including allergies and asthma, are the result of complex gene-environment interactions. One of the most challenging questions in this regard relates to the biochemical mechanism of how exogenous environmental trigger factors modulate and modify gene expression, subsequently leading to the development of chronic inflammatory conditions. Epigenetics comprises the umbrella of biochemical reactions and mechanisms, such as DNA methylation and chromatin modifications on histones and other structures. Recently, several lifestyle and environmental factors have been investigated in terms of such biochemical interactions with the gene expression-regulating machinery: allergens; microbes and microbial compounds; dietary factors, including vitamin B12, folic acid, and fish oil; obesity; and stress. This article aims to update recent developments in this context with an emphasis on allergy and asthma research.

Role of omega-3 fatty acids and their metabolites in asthma and allergic diseases

Omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are found naturally in fish oil and are commonly thought to be anti-inflammatory nutrients, with protective effects in inflammatory diseases including asthma and allergies. The mechanisms of these effects remain mostly unknown but are of great interest for their potential therapeutic applications. Large numbers of epidemiological and observational studies investigating the effect of fish intake or omega-3 fatty acid supplementation during pregnancy, lactation, infancy, childhood, and adulthood on asthmatic and allergic outcomes have been conducted. They mostly indicate protective effects and suggest a causal relationship between decreased intake of fish oil in modernized diets and an increasing number of individuals with asthma or other allergic diseases. Specialized pro-resolving mediators (SPM: protectins, resolvins, and maresins) are generated from omega-3 fatty acids such as EPA and DHA via several enzymatic reactions. These mediators counter-regulate airway eosinophilic inflammation and promote the resolution of inflammation in vivo. Several reports have indicated that the biosynthesis of SPM is impaired, especially in severe asthma, which suggests that chronic inflammation in the lung might result from a resolution defect. This article focuses on the beneficial aspects of omega-3 fatty acids and offers recent insights into their bioactive metabolites including resolvins and protectins.

Fish allergy: in review

Globally, the rising consumption of fish and its derivatives, due to its nutritional value and divergence of international cuisines, has led to an increase in reports of adverse reactions to fish. Reactions to fish are not only mediated by the immune system causing allergies, but are often caused by various toxins and parasites including ciguatera and Anisakis. Allergic reactions to fish can be serious and life threatening and children usually do not outgrow this type of food allergy. The route of exposure is not only restricted to ingestion but include manual handling and inhalation of cooking vapors in the domestic and occupational environment. Prevalence rates of self-reported fish allergy range from 0.2 to 2.29 % in the general population, but can reach up to 8 % among fish processing workers. Fish allergy seems to vary with geographical eating habits, type of fish processing, and fish species exposure. The major fish allergen characterized is parvalbumin in addition to several less well-known allergens. This contemporary review discusses interesting and new findings in the area of fish allergy including demographics, novel allergens identified, immunological mechanisms of sensitization, and innovative approaches in diagnosing and managing this life-long disease.

A systematic review of associations between environmental exposures and development of asthma in children aged up to 9 years

OBJECTIVES

Childhood asthma is a complex condition where many environmental factors are implicated in causation. The aim of this study was to complete a systematic review of the literature describing associations between environmental exposures and the development of asthma in young children.

SETTING

A systematic review of the literature up to November 2013 was conducted using key words agreed by the research team. Abstracts were screened and potentially eligible papers reviewed. Papers describing associations between exposures and exacerbation of pre-existing asthma were not included. Papers were placed into the following predefined categories: secondhand smoke (SHS), inhaled chemicals, damp housing/mould, inhaled allergens, air pollution, domestic combustion, dietary exposures, respiratory virus infection and medications.

PARTICIPANTS

Children aged up to 9 years.

PRIMARY OUTCOMES

Diagnosed asthma and wheeze.

RESULTS

14,691 abstracts were identified, 207 papers reviewed and 135 included in the present review of which 15 were systematic reviews, 6 were meta-analyses and 14 were intervention studies. There was consistent evidence linking exposures to SHS, inhaled chemicals, mould, ambient air pollutants, some deficiencies in maternal diet and respiratory viruses to an increased risk for asthma (OR typically increased by 1.5-2.0). There was less consistent evidence linking exposures to pets, breast feeding and infant dietary exposures to asthma risk, and although there were consistent associations between exposures to antibiotics and paracetamol in early life, these associations might reflect reverse causation. There was good evidence that exposures to house dust mites (in isolation) was not associated with asthma risk. Evidence from observational and intervention studies suggest that interactions between exposures were important to asthma causation, where the effect size was typically 1.5-3.0.

CONCLUSIONS

There are many publications reporting associations between environmental exposures and modest changes in risk for asthma in young children, and this review highlights the complex interactions between exposures that further increase risk.

Fish and rapeseed oil consumption in infants and mothers: dietary habits and determinants in a nationwide sample in Germany

PURPOSE

Fish and rapeseed oil are major sources of omega-3 polyunsaturated fatty acids (n-3 PUFA) in complementary food, but little is known about current consumption in Germany.

METHODS

We conducted a nationwide consumer survey to assess the consumption habits of fish and rapeseed oil and their determining factors in 985 mother-child dyads in Germany.

RESULTS

One-fourth of infants ate fish as often as recommended, i.e. at least once per week. Half of the mothers stated that they mainly used rapeseed oil for self-prepared and/or commercial vegetable-potato-meat meals. In contrast, mothers more frequently met recommendations for fish consumption (41 %), but used rapeseed oil (34 %) less often for their own nutrition. Maternal eating behaviour was the most important predictor for both of these n-3 PUFA rich foods in infants' nutrition. In contrast to infants' fish consumption, rapeseed oil intake in infancy was found to be influenced by some further factors, i.e. mothers' social class and omega-3 knowledge, which were also key determinants of mothers' own fish and rapeseed oil consumption.

CONCLUSION

To promote fish with complementary feeding, programs should focus on families whose mothers rarely eat fish. Nutritional campaigns to improve omega-3 knowledge-especially focusing on lower social classes-could be effective in increasing rapeseed oil consumption, although these programs should be combined with environmental improvements as it has been already started through the use of rapeseed oil in commercial baby jars.

Dietary exposures and allergy prevention in high-risk infants: a joint position statement of the Canadian Society of Allergy and Clinical Immunology and the Canadian Paediatric Society

Allergic conditions in children are a prevalent health concern in Canada. The burden of disease and the societal costs of proper diagnosis and management are considerable, making the primary prevention of allergic conditions a desirable health care objective. This position statement reviews current evidence on dietary exposures and allergy prevention in infants at high risk of developing allergic conditions. It revisits previous dietary recommendations for pregnancy, breastfeeding and formula-feeding, and provides an approach for introducing solid foods to high-risk infants. While there is no evidence that delaying the introduction of any specific food beyond six months of age helps to prevent allergy, the protective effect of early introduction of potentially allergenic foods (at four to six months) remains under investigation. Recent research appears to suggest that regularly ingesting a new, potentially allergenic food may be as important as when that food is first introduced. This article has already been published (Paediatr Child Health. 2013 Dec;18(10):545–54), and is being re-published with permission from the original publisher, the Canadian Paediatric Society.

Serum fatty acid profile does not reflect seafood intake in adolescents with atopic eczema

AIM

Long-chain polyunsaturated fatty acids (LCPUFAs) are immunomodulatory, but their role in allergy development is controversial. We investigated whether proportions of LCPUFAs in serum phospholipids were related to allergic diagnosis, seafood intake and LCPUFA proportions in cord blood.

METHODS

Serum was obtained from 148 birth cohort children at 13 years of age. Forty had atopic eczema, 53 had respiratory allergy, and 55 were nonallergic. Proportions of LCPUFAs were determined in serum phospholipids; cord blood from 128 of the individuals was previously analysed. Seafood intake was estimated using questionnaires.

RESULTS

Allergic and nonallergic individuals did not differ significantly regarding individual LCPUFAs. However, arachidonic acid over docosahexaenoic acid (DHA) ratio was higher in allergic, compared with nonallergic, adolescents. In nonallergic individuals, LCPUFA proportions in cord serum and adolescent serum correlated weakly. In individuals with atopic eczema and respiratory allergy, these correlations were weak or absent. A moderate correlation between seafood intake and serum DHA was seen in nonallergic individuals and those with respiratory allergy, but not in those with atopic eczema.

CONCLUSION

Serum LCPUFA pattern was similar in allergic and nonallergic adolescents. Fatty acid metabolism may be altered in atopic eczema subjects, suggested by poor correlations between fatty acid intake and serum levels.

Antibiotics in the first week of life is a risk factor for allergic rhinitis at school age

BACKGROUND

Heredity as well as external factors influences the development of allergic rhinitis. The aim of this study was to analyse early risk factors and protective factors for allergic rhinitis at school age.

METHODS

This is a prospective, longitudinal study of children born in western Sweden in 2003 where 50% of the birth cohort was randomly selected. The parents answered questionnaires at 6 months, 12 months, 4.5 yr and 8 yr. At 8 yr, 5044 questionnaires were distributed. Of these, 4051 responded, that is, 80.3%. Current allergic rhinitis was defined as symptoms and use of medication during the past 12 months.

RESULTS

Current allergic rhinitis at 8 yr was reported by 10.9%. Mean onset age was 5.7 yr, and 61.9% were boys. In a multivariate analysis, antibiotics in the first week of life increased the risk of allergic rhinitis (adjusted odds ratio 1.75, 95% confidence interval (1.03, 2.97)). Increased risk was also seen with parental allergic rhinitis (aOR 2.73 (2.12, 3.52)), food allergy first year (aOR 2.45 (1.61, 3.73)), eczema first year (aOR 1.97 (1.50, 2.59)) and male gender (aOR 1.35 (1.05, 1.74)). Living on a farm at 4.5 yr reduced the risk (aOR 0.31 (0.13, 0.78)).

CONCLUSION

Antibiotics in the first week of life increased the risk of allergic rhinitis at school age, while living on a farm at preschool age reduced the risk. Both findings are compatible with the hygiene hypothesis.

Primary prevention of food allergy in children and adults: systematic review

BACKGROUND

Food allergies can have serious physical, social, and financial consequences. This systematic review examined ways to prevent the development of food allergy in children and adults.

METHODS

Seven bibliographic databases were searched from their inception to September 30, 2012, for systematic reviews, randomized controlled trials, quasi-randomized controlled trials, controlled clinical trials, controlled before-and-after studies, interrupted time series studies, and prospective cohort studies. Experts were consulted for additional studies. There were no language or geographic restrictions. Two reviewers appraised the studies using appropriate tools. Data were not suitable for meta-analysis due to heterogeneity, so were narratively synthesized.

RESULTS

Seventy-four studies were included, one-third of which were of high quality. There was no good evidence to recommend that pregnant or breastfeeding women should change their diet or take supplements to prevent allergies in infants at high or normal risk. There were mixed findings about the preventive benefits of breastfeeding for infants at high or normal risk, but there was evidence to recommend avoiding cow's milk and substituting with extensively or partially hydrolyzed whey or casein formulas for infants at high risk for the first 4 months. Soy milk and delaying the introduction of solid foods beyond 4 months did not have preventive benefits in those at high or normal risk. There was very little evidence about strategies for preventing food allergy in older children or adults.

CONCLUSIONS

There is much to learn about preventing food allergy, and this is a priority given the high societal and healthcare costs involved.

EAACI food allergy and anaphylaxis guidelines. Primary prevention of food allergy

Food allergy can have significant effects on morbidity and quality of life and can be costly in terms of medical visits and treatments. There is therefore considerable interest in generating efficient approaches that may reduce the risk of developing food allergy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Prevention and is part of the EAACI Guidelines for Food Allergy and Anaphylaxis. It aims to provide evidence-based recommendations for primary prevention of food allergy. A wide range of antenatal, perinatal, neonatal, and childhood strategies were identified and their effectiveness assessed and synthesized in a systematic review. Based on this evidence, families can be provided with evidence-based advice about preventing food allergy, particularly for infants at high risk for development of allergic disease. The advice for all mothers includes a normal diet without restrictions during pregnancy and lactation. For all infants, exclusive breastfeeding is recommended for at least first 4-6 months of life. If breastfeeding is insufficient or not possible, infants at high-risk can be recommended a hypoallergenic formula with a documented preventive effect for the first 4 months. There is no need to avoid introducing complementary foods beyond 4 months, and currently, the evidence does not justify recommendations about either withholding or encouraging exposure to potentially allergenic foods after 4 months once weaning has commenced, irrespective of atopic heredity. There is no evidence to support the use of prebiotics or probiotics for food allergy prevention.

Dietary exposures and allergy prevention in high-risk infants: A joint statement with the Canadian Society of Allergy and Clinical Immunology

Allergic conditions in children are a prevalent health concern in Canada. The burden of disease and the societal costs of proper diagnosis and management are considerable, making the primary prevention of allergic conditions a desirable health care objective. This position statement reviews current evidence on dietary exposures and allergy prevention in infants at high risk for developing allergic conditions. It revisits previous dietary recommendations for pregnancy, breastfeeding and formula feeding, and provides an approach for introducing solid foods to high-risk infants. While there is no evidence that delaying the introduction of any specific food beyond six months of age helps to prevent allergy, the protective effect of early introduction of potentially allergenic foods (at four to six months of age) remains under investigation. Recent research appears to suggest that regularly ingesting a new, potentially allergenic food may be as important as when that food is first introduced.

Fish and fish oil intake in relation to risk of asthma: a systematic review and meta-analysis

Although laboratory studies suggest that long-chain n-3 polyunsaturated fatty acids (LCn3PUFAs) may reduce risk of asthma, epidemiological data remain controversial and inconclusive. We quantitatively reviewed the epidemiological studies published through December 2012 in PubMed and EMBASE by using a fixed-effects or random-effects model. Eleven studies, comprised of 99,093 individuals (3,226 cases), were included in the final dataset. Of them, 7 studies examined associations between intake of fish or LCn3PUFA and risk of asthma: 4 studies in children (996 cases from 12,481 children) and 3 in adults (1,311 cases from 82,553 individuals). Two studies (69 cases from 276 infants) investigated LCn3PUFA levels in mothers' milk, and two studies assessed maternal fish consumption (786 cases from 2,832 individuals) during lactation and/or plasma LCn3PUFA levels during pregnancy (64 cases from 951 infants) in relation to offspring's asthma. The pooled relative risk of child asthma were 0.76 (95% CI, 0.61-0.94) for fish consumption and 0.71 (95% CI, 0.52-0.96) for LCn3PUFA intake. No statistically significant association was found in studies among adults. Epidemiological data to date indicate that fish or LCn3PUFA intake may be beneficial to prevent asthma in children. Further studies are needed to establish causal inference and to elucidate the potential mechanisms.

Early exposure to allergens: a new window of opportunity for non-communicable disease prevention in complementary feeding?

Recent findings suggest that an early exposure to dietary antigens may be more protective towards allergy than a later introduction even in high-risk infants. The consequent earlier introduction of food items such as egg yolk and oily fish, together with breastfeeding continuation through the first year, could contribute to reducing protein and increasing fat supply, respectively. These changes might have a role in the overall prevention of non-communicable disorders of adulthood.

Diet and allergic diseases among population aged 0 to 18 years: myth or reality?

Allergic diseases are an important health problem. However, epidemiological studies concerning childhood diet-related allergic diseases are scarce. This review examines published articles dealing with diet, dietary patterns and nutrition in relation with allergic diseases among population aged 0 to 18 years. Studies and trials were identified using MEDLINE/PubMed and Cochrane Database of Systematic Reviews and were limited to those published in English or French from 1992 until 2012. This manuscript also reviews the evidence for maternal diet during pregnancy and diet during early childhood and their association with childhood atopic diseases, taking into account the methodology used to evaluate dietary patterns. The evidence reviewed is derived from large epidemiological studies exploring the effects of different food categories on asthma, atopic dermatitis, and allergic rhinitis in children. Overall, maternal diet during pregnancy and a childhood diet rich in antioxidants and omega-3 fatty acids are considered as healthy diets that could be protective for allergic diseases in childhood.

High levels of both n-3 and n-6 long-chain polyunsaturated fatty acids in cord serum phospholipids predict allergy development

BACKGROUND

Long-chain polyunsaturated fatty acids (LCPUFAs) reduce T-cell activation and dampen inflammation. They might thereby counteract the neonatal immune activation and hamper normal tolerance development to harmless environmental antigens. We investigated whether fatty acid composition of cord serum phospholipids affects allergy development up to age 13 years.

METHODS

From a population-based birth-cohort born in 1996/7 and followed until 13 years of age (n = 794), we selected cases with atopic eczema (n = 37) or respiratory allergy (n = 44), as well as non-allergic non-sensitized controls (n = 48) based on diagnosis at 13 years of age. Cord and maternal sera obtained at delivery from cases and controls were analysed for proportions of saturated, monounsaturated and polyunsaturated fatty acids among serum phospholipids.

RESULTS

The cord serum phospholipids from subject who later developed either respiratory allergy or atopic eczema had significantly higher proportions of 5/8 LCPUFA species, as well as total n-3 LCPUFA, total n-6 LCPUFA and total LCPUFA compared to cord serum phospholipids from controls who did not develop allergy (P<0.001 for all comparisons). Conversely, individuals later developing allergy had lower proportion of the monounsaturated fatty acid 18∶1n-9 as well as total MUFA (p<0.001) among cord serum phospholipids. The risk of respiratory allergy at age 13 increased linearly with the proportion of n-3 LCPUFA (Ptrend<0.001), n-6 LCPUFA (Ptrend = 0.001), and total LCPUFA (Ptrend<0.001) and decreased linearly with the proportions of total MUFA (Ptrend = 0.025) in cord serum phospholipids. Furthermore, Kaplan-Meier estimates of allergy development demonstrated that total LCPUFA proportion in cord serum phospholipids was significantly associated with respiratory allergy (P = 0.008) and sensitization (P = 0.002), after control for sex and parental allergy.

CONCLUSION

A high proportion of long-chain PUFAs among cord serum phospholipids may predispose to allergy development. The mechanism is unknown, but may involve dampening of the physiologic immune activation in infancy needed for proper maturation of the infant's immune system.

Early regular egg exposure in infants with eczema: A randomized controlled trial

BACKGROUND

Observational studies suggest that early regular ingestion of allergenic foods might reduce the risk of food allergy.

OBJECTIVE

We sought to determine whether early regular oral egg exposure will reduce subsequent IgE-mediated egg allergy in infants with moderate-to-severe eczema.

METHODS

In a double-blind, randomized controlled trial infants were allocated to 1 teaspoon of pasteurized raw whole egg powder (n = 49) or rice powder (n = 37) daily from 4 to 8 months of age. Cooked egg was introduced to both groups after an observed feed at 8 months. The primary outcome was IgE-mediated egg allergy at 12 months, as defined based on the results of an observed pasteurized raw egg challenge and skin prick tests.

RESULTS

A high proportion (31% [15/49]) of infants randomized to receive egg had an allergic reaction to the egg powder and did not continue powder ingestion. At 4 months of age, before any known egg ingestion, 36% (24/67) of infants already had egg-specific IgE levels of greater than 0.35 kilounits of antibody (kUA)/L. At 12 months, a lower (but not significant) proportion of infants in the egg group (33%) were given a diagnosis of IgE-mediated egg allergy compared with the control group (51%; relative risk, 0.65; 95% CI, 0.38-1.11; P = .11). Egg-specific IgG4 levels were significantly (P < .001) greater in the egg group at both 8 and 12 months.

CONCLUSION

Induction of immune tolerance pathways and reduction in egg allergy incidence can be achieved by early regular oral egg exposure in infants with eczema. Caution needs to be taken when these high-risk infants are first exposed to egg because many have sensitization already by 4 months of age.

Fish consumption in infancy and development of allergic disease up to age 12 y

BACKGROUND

Fish intake in infancy has been associated with reduced risk of allergic disease in early childhood, but it is unknown whether this effect remains as children grow older.

OBJECTIVE

We studied the possible effect of fish consumption in infancy on prevalent and incident allergic disease up to the age of 12 y.

DESIGN

A total of 3285 children from a prospective Swedish birth cohort (Children, Asthma, Milieu, Stockholm, Epidemiology) were included in the current analyses. At 1, 2, 4, 8, and 12 y, parental questionnaires were used to obtain information on lifestyle factors, environmental exposures, and symptoms of allergic disease. The frequency of fish intake in infancy was assessed in the 1-y questionnaire. Serum immunoglobulin (Ig) E concentrations associated with common allergens were obtained at age 8 y. Generalized estimating equations and multivariate logistic regression were used to examine associations between fish consumption in infancy and prevalent and incident allergic disease at ages 1-12 y, including sensitization and IgE-associated disease at age 8 y.

RESULTS

At 1 y of age, 80% of the children consumed fish regularly (ie, ≥2 times/mo). From 1 to 12 y of age, regular fish consumption in infancy reduced overall risks of prevalent and incident allergic disease [adjusted OR (95% CI) after restriction to children without early symptoms of allergic disease was 0.74 (0.60, 0.90) (P = 0.003) for prevalent rhinitis and 0.78 (0.63, 0.97) (P = 0.028) for prevalent eczema.

CONCLUSION

Regular fish consumption in infancy may reduce risk of allergic disease up to age 12 y.