Food Allergy: What We Know Now

Omalizumab for the reduction of allergic reactions to foods: a narrative review

The frequency of food allergies varies between 2% and 10%, depending on characteristics including age, region, race, and method of diagnosis self-reported by patients or oral food challenges (OFCs). The most common allergies reported are tree nuts (1.2%), milk (1.9%), peanuts (2.2%), and shellfish (1.3%). Omalizumab injection has now been approved by the FDA for the treatment of immunoglobulin E-mediated food allergies in specific adults and children aged one year or older. This medication reduces the risk of allergic reactions (Type I), which can include anaphylaxis, when an individual accidentally encounters one or more food allergens. Omalizumab functions by binding to IgE and altering IgE-mediated pathways, which lessens IgE's capacity to cause allergic reactions. Promising outcomes from clinical trials and case studies include lowered anaphylactic risk and enhanced tolerance to allergens. Omalizumab, however, may have adverse effects; thus, close observation is required. Overall, this review sheds light on the efficacy, safety, and clinical implications of omalizumab, highlighting its potential as a useful intervention for IgE-mediated food allergies.

Food allergy knowledge, attitude and management among preschool personnel in Malaysia

BACKGROUND

Children are vulnerable, and they may experience their first serious food allergy reaction at school, where they spend much of their time. The present study aims to determine the level of food allergy knowledge, attitude and management (KAM) among preschool personnel in Klang Valley, Malaysia.

METHODS

A cross-sectional study was conducted with 292 personnel working in Klang Valley preschools. The participants completed an online questionnaire asking about sociodemographic information and food allergy KAM. Mann-Whitney U and chi-squared tests were used to compare the KAM level between public and private preschool personnel and examine the association of KAM of food allergy with various sociodemographic factors, respectively.

RESULTS

Some 86.3% of the participants demonstrated a low level of food allergy knowledge, 64.7% showed a negative food allergy attitude and 57.9% indicated fair food allergy management. The total mean score for food allergy knowledge was higher (p < 0.01) among the private preschool personnel compared to the public group, although there was no significant difference in attitude (p = 0.244) or practice (p = 0.171). Age group (p < 0.01) and monthly income (p < 0.05) were significantly associated with the level of attitude, whereas no sociodemographic factor was associated with knowledge and management of food allergy.

CONCLUSIONS

Most preschool personnel in Klang Valley have a low level of food allergy knowledge, negative attitudes and a fair level of ability to manage food allergy reactions. The findings of the present study may guide future studies to improve the food allergy KAM of preschool personnel and provide a safer environment for children with food allergies.

Expression, purification, characterization, and patient IgE reactivity of new macadamia nut iso-allergen

Structural and functional information about food allergens is essential for understanding the allergenicity of food proteins. All allergens belong to a small number of protein families. Various allergens from different families have been successfully produced recombinantly in E. coli for their characterization and applications in allergy diagnosis and treatment. However, recombinant hexameric 11S seed storage protein has not been reported, although numerous 11S legumins are known to be food allergens, including the recently identified macadamia nut allergen Mac i 2. Here we report the production of a macadamia nut legumin by expressing it in E. coli with a substrate site of HRV 3C protease and cleaving the purified protein with HRV 3C protease. The protease divided the protein into two chains and left a native terminus for the C-terminal chain, resulting in a recombinant hexameric 11S allergen for the first time after the residues upstream to the cleavage site flipped out of the way of the trimer-trimer interaction. The 11S allergens are known to have multiple isoforms in many species. The present study removed an obstacle in obtaining homogeneous allergens needed for studying allergens and mitigating allergenicity. Immunoreactivity of the protein with serum IgE confirmed it to be a new isoform of Mac i 2.

IgE binding epitope mapping with TL1A tagged peptides

Linear IgE epitopes play essential roles in persistent allergies, including peanut and tree nut allergies. Using chemically synthesized peptides attached to membranes and microarray experiments is one approach for determining predominant epitopes that has seen success. However, the overall expense of this approach and the inherent challenges in scaling up the production and purification of synthetic peptides precludes the general application of this approach. To overcome this problem, we have constructed a plasmid vector for expressing peptides sandwiched between an N-terminal His-tag and a trimeric protein. The vector was used to make overlapping peptides derived from peanut allergens Ara h 2. All the peptides were successfully expressed and purified. The resulting peptides were applied to identify IgE binding epitopes of Ara h 2 using four sera samples from individuals with known peanut allergies. New and previously defined dominant IgE binding epitopes of Ara h 2 were identified. This system may be readily applied to produce agents for component- and epitope-resolved food allergy diagnosis.

Labeling food allergens in the packaged food pyramid groups in Brazil: analysis of descriptions, ambiguities, and risks

OBJECTIVE

The aim of this study was to evaluate allergenic labeling components of packaged foods for "What is the quality of food labels?" and "What is the group of Brazilian Food Pyramid that 'May contain' is predominant?."

METHODS

The photographs of 916 products were obtained, of which 518 were analyzed. Data from each label were evaluated according to Brazilian Food Pyramid Groups (i.e., Cereals, Fruits, & Vegetables; Soybean & products; Milk & dairy products; Meat & eggs; Fats & oils; and Sugars & sweets). Ten items were analyzed in each label, namely, the presence of a list of ingredients, alert phrase for allergy sufferers, grouping of the alert phrase, phrase location, uppercase phrase, the phrase in bold, the color of alert phrase contrasting to the background, adequate font size, do not claim the absence for any allergen with the ingredients, and others factors that make it difficult to read. For the second question, a structured questionnaire was completed, and products were classified into two categories, namely, "Contain" and "May contain."

RESULTS

The quality of the label was appropriate, and 69% of packaged foods had at least one allergen. The information "May contain" were higher in cow's milk (Cereals and Meat & eggs), soy (Soybean & products), and egg protein (Cereals). Soybean & products were the highest insecurity group.

CONCLUSIONS

Brazilian health professionals can count on good-quality labeling of packaged products. Consequently, they could promote patients' and parents/caregivers' education to consult the labels and manage the risks in processed foods about precautionary allergen labeling. Soybean & products were the most significant insecurity for food choices between Brazilian Pyramid Groups.

Effect of Lactic Acid Fermentation on Legume Protein Properties, a Review

Legume proteins have a promising future in the food industry due to their nutritional, environmental, and economic benefits. However, their application is still limited due to the presence of antinutritional and allergenic compounds, their poor technological properties, and their unpleasant sensory characteristics. Fermentation has been traditionally applied to counteract these inconveniences. At present, lactic acid fermentation of legumes is attracting the attention of researchers and industry in relation to the development of healthier, tasty, and technologically adapted products. Hence, we aimed to review the literature to shed light on the effect of lactic acid fermentation on legume protein composition and on their nutritional, functional, technological, and sensorial properties. The antimicrobial activity of lactic acid bacteria during legume fermentation was also considered. The heterogenicity of raw material composition (flour, concentrate, and isolate), the diversity of lactic acid bacteria (nutriment requirements, metabolic pathways, and enzyme production), and the numerous possible fermenting conditions (temperature, time, oxygen, and additional nutrients) offer an impressive range of possibilities with regard to fermented legume products. Systematic studies are required in order to determine the specific roles of the different factors. The optimal selection of these criteria will allow one to obtain high-quality fermented legume products. Fermentation is an attractive technology for the development of legume-based products that are able to satisfy consumers’ expectations from a nutritional, functional, technological, and sensory point of view.

Rotulagem de alérgenos alimentares em alimentos embalados segundo grupos alimentares da pirâmide brasileira: análise da descrição, riscos e ambiguidades

RESUMO Objetivo: Avaliar os componentes alergênicos da rotulagem de alimentos embalados e responder “Qual é a qualidade da rotulagem?” e “Qual é o grupo de alimentos em que a expressão ‘Pode conter’ é predominante?”. Métodos: Foram obtidas fotografias de 916 produtos, dos quais 518 foram analisados. Os dados dos rótulos foram avaliados de acordo com os grupos da pirâmide alimentar brasileira (Cereais, Frutas & Vegetais; Soja & Derivados; Leite & Laticínios; Carne & Ovos; Gorduras & Óleos; Açúcares & Doces). Dez itens foram analisados nos rótulos: presença de lista de ingredientes; frase de alerta para alérgicos; frase de alerta; local da frase; frase em letras maiúsculas; frase em negrito; a cor da frase de alerta contrastando com o fundo; tamanho de fonte adequado; não alegar ausência de qualquer alérgeno; outros fatores de difícil leitura. Para a segunda questão, foi respondido questionário estruturado, e os produtos classificados em categorias: “Contém” e “Pode conter”. Resultados: A qualidade do rótulo foi adequada e 69% dos alimentos embalados continham pelo menos um alérgeno. A informação “Pode conter” foi mais identificada em: proteína do leite (Cereais e Carnes e ovos), soja (Soja & derivados) e proteína do ovo (Cereais). Soja e derivados foi o grupo alimentar de maior insegurança. Conclusões: Profissionais de saúde podem contar com rotulagem de boa qualidade dos produtos embalados e, consequentemente, promover a educação de pais/cuidadores para consultar os rótulos e gerenciar os riscos em alimentos processados. Soja e produtos são os alimentos com maior insegurança entre os Grupos da Pirâmide Brasileira.

Responses of consumers with food allergy to the new allergen-labelling legislation in Saudi Arabia: a preliminary survey

OBJECTIVE

Preventing a food allergy reaction depends primarily on eliminating allergens from the diet. In October 2019, the Saudi Food and Drug Authority (SFDA) introduced new legislation requiring food establishments providing and selling non-prepacked foods to state the presence of the top fourteen food allergens on their menus. The current study aimed to assess the allergen-labelling knowledge, practices, preferences and perceptions towards the new SFDA allergen-labelling legislation among consumers with food allergy in Saudi Arabia.

DESIGN

Observational cross-sectional study using an online questionnaire.

SETTING

Saudi Arabia; February - March 2020.

PARTICIPANTS

Residents of Saudi Arabia with food allergy (n 427), aged 18-70 years.

RESULTS

Among participants, only 28·1 % knew that there were governmental regulations in Saudi Arabia regarding food-allergen labelling and approximately two-thirds (67 %) check labels on prepacked food products for allergens. The majority of the participants preferred food products carrying safety statements (84·1 %) and symbols (80·1 %). A total of 47·1 % were aware that regulations in Saudi Arabia require allergens to be declared in ingredient lists, while 51·3 % were aware that advisory allergen labelling is not required by law. Only 26·2 % were aware of the new SFDA legislation regarding provision of allergen information by food establishments. However, the majority (94·4 %) were supportive of the new legislation, and most of them were more likely to eat at restaurants that reported allergen information for food items on the menu.

CONCLUSIONS

The new SFDA food allergen-labelling legislation needs to be more widely and effectively disseminated to increase the level of awareness among adults with food allergy in Saudi Arabia.

An Updated Overview of Almond Allergens

Tree nuts are considered an important food in healthy diets. However, for part of the world’s population, they are one of the most common sources of food allergens causing acute allergic reactions that can become life-threatening. They are part of the Big Eight food groups which are responsible for more than 90% of food allergy cases in the United States, and within this group, almond allergies are persistent and normally severe and life-threatening. Almond is generally consumed raw, toasted or as an integral part of other foods. Its dietary consumption is generally associated with a reduced risk of cardiovascular diseases. Several almond proteins have been recognized as allergens. Six of them, namely Pru du 3, Pru du 4, Pru du 5, Pru du 6, Pru du 8 and Pru du 10, have been included in the WHO-IUIS list of allergens. Nevertheless, further studies are needed in relation to the accurate characterization of the already known almond allergens or putative ones and in relation to the IgE-binding properties of these allergens to avoid misidentifications. In this context, this work aims to critically review the almond allergy problematic and, specifically, to perform an extensive overview regarding known and novel putative almond allergens.

IgE-mediated food allergy throughout life

Food allergy (FA) has become an increasing problem throughout the world. Over the last 2 decades, the frequency of FA has increased in both children and adults. The prevalence differs according to the research methodology, age, and geographic regions, ranging between 2.0% and 10.0%. The most common form of FA is immunoglobulin E (IgE)-mediated FA. In this form, patients may present with life-threatening conditions, such as anaphylaxis, or milder conditions, such as urticaria, angioedema, sneezing, and nausea alone. The gold standard in the diagnosis of FA is oral provocation tests. Epidermal skin prick tests and specific IgE measurements, as well as component-resolved diagnostic techniques are helpful in the diagnosis and follow-up of patients. In this review, the epidemiology, diagnosis, follow-up, and prognosis of IgE-mediated FA in children and adults were discussed and some specific forms of FA, such as pollen FA syndrome, alpha-gal allergy, and food-dependent exercise-induced anaphylaxis were explained.

Almond allergens: update and perspective on identification and characterization

Almond (Prunus dulcis) is not only widely used as a human food as a result of its flavor, nutrients, and health benefits, but it is also one of the most likely tree nuts to trigger allergies. Almond allergens, however, have not been studied as extensively as those of peanuts and other selected tree nuts. This review provides an update of the molecular properties of almond allergens to clarify some confusion about the identities of almond allergens and our perspective on characterizing putative almond allergens. At present, the following almond allergens have been designated by the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Sub-Committee: Pru du 3 (a non-specific lipid transfer protein 1, nsLTP1), Pru du 4 (a profilin), Pru du 5 (60S acidic ribosomal protein 2), Pru du 6 (an 11S legumin known as prunin) and Pru du 8 (an antimicrobial protein with cC3C repeats). Besides, almond vicilin and almond γ-conglutin have been identified as food allergens, although further characterization of these allergens is still of interest. In addition, almond 2S albumin was reported as a food allergen as a result of the misidentification of Pru du 8. Two more almond proteins have been called allergens based on their sequence homology with known food allergens and their 'membership' in relevant protein families that contain allergens in many species. These include the pathogenesis related-10 protein (referred to as Pru du 1) and the thaumatin-like protein (referred to as Pru du 2). Almonds thus have five known food allergens and five more likely ones that need to be investigated further. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Almond (Prunus dulcis) Allergen Pru du 8, the First Member of a New Family of Food Allergens

An almond allergen with two known short peptide sequences was reported as the almond 2S albumin but was later suspected to be almond vicilin. However, this allergen was not designated by the World Health Organization/International Union of Immunological Societies. This study aimed to determine the true identity of this elusive almond allergen. cDNAs were synthesized from total RNA of the Nonpareil almond. The complete sequence of the previously reported almond allergen was determined from its coding sequence. The deduced protein was produced recombinantly and was confirmed to be a food allergen by testing with 18 almond-allergic sera. The allergen is a potential cysteine-rich antimicrobial protein with characteristic C[X]₃C-[X]_10-12-C[X]₃C motifs of the hairpinin antimicrobial protein. This first member of a novel family of food allergens was named Pru du 8. The signature motif of the hairpinin antimicrobial protein can be found in the N-terminal region of some vicilin allergens (e.g., Ara h 1). It can also be found in the signal peptide of other vicilin allergens (e.g., Car i 2). In many species, however, vicilins do not contain such a motif, indicating that the presence of the signature motifs of the hairpinin antimicrobial protein in vicilins might be a result of translocation during evolution.

Food allergen knowledge, attitude and practices among UK consumers: A structural modelling approach

Food allergies are becoming more prevalent and affect up to 1-2% of adults and 5-8% of children in the UK. This study investigated the food allergen knowledge, attitude towards food allergens and food allergy management practices among food allergic and intolerant consumers and/or their family members and carers. Questionnaires were distributed at three major Free From events in the UK in 2017 and 2018. Structural Equation Modelling (SEM) was used as a confirmatory technique to determine the model's validity. Cereals containing gluten, milk and eggs were the most common triggers reported by the consumers. Other trigger foods such as chocolate, garlic, maize, onions, red and white meat, spices, and fruits such as apples and cherries were also reported. Consumers demonstrated very good understanding on the severity of allergic reactions, prevention method and hidden egg ingredients. Overall, consumers were relatively good in the knowledge section. The participants were motivated in their personal allergen avoidance towards food allergens especially in checking food labels, preference for more free from product choices and handwashing. Consumers did not rely on dietary apps or social media to find out about allergen-free food products. Both knowledge and attitude did not translate into food allergy management practices. Significant correlation between knowledge and attitude was identified suggesting that as knowledge decreases, so will their attitude scores. This study suggests that targeted and systematic food allergy management topics and peer support could be used to improve consumers' knowledge and attitude to positively impact food allergen handling practices.

Dietary Effects on Microbiota-New Trends with Gluten-Free or Paleo Diet

A well-balanced diet is the basis for a healthy life. Both the western diet and special diets can have a relevant impact on the microbiome and promote the development of various diseases. There has been an increase in food-related disorders in recent years, largely associated with dramatic changes in food consumption trends and main nutrients. A major response to food intolerances has been the adoption of new dietary trends involving the reduction or exclusion of specific food ingredients. Especially gluten-containing, but also gluten-free cereals are in the cross-fire. Supporters of the gluten-free diet argue that gluten triggers inflammation and related diseases, while followers of the Paleo diet drastically impeach all cereals as dangerous for human health. To date, no controlled studies support or reject a positive health effect of a gluten-free or cereal-free diet. Future large-scale studies need to evaluate the effect of gluten-containing and gluten-free cereals and the various diets on human health, inflammatory parameters, clinical symptoms, and the gut microbiota (including the bacteria, fungi, and viruses). Dietary-associated changes in compositional and functional microbiota traits should be correlated with the health status for the future development of dietary recommendations and potential clinical interventions.

Neuro-immune interactions in allergic diseases: novel targets for therapeutics

Recent studies have highlighted an emerging role for neuro-immune interactions in mediating allergic diseases. Allergies are caused by an overactive immune response to a foreign antigen. The peripheral sensory and autonomic nervous system densely innervates mucosal barrier tissues including the skin, respiratory tract and gastrointestinal (GI) tract that are exposed to allergens. It is increasingly clear that neurons actively communicate with and regulate the function of mast cells, dendritic cells, eosinophils, Th2 cells and type 2 innate lymphoid cells in allergic inflammation. Several mechanisms of cross-talk between the two systems have been uncovered, with potential anatomical specificity. Immune cells release inflammatory mediators including histamine, cytokines or neurotrophins that directly activate sensory neurons to mediate itch in the skin, cough/sneezing and bronchoconstriction in the respiratory tract and motility in the GI tract. Upon activation, these peripheral neurons release neurotransmitters and neuropeptides that directly act on immune cells to modulate their function. Somatosensory and visceral afferent neurons release neuropeptides including calcitonin gene-related peptide, substance P and vasoactive intestinal peptide, which can act on type 2 immune cells to drive allergic inflammation. Autonomic neurons release neurotransmitters including acetylcholine and noradrenaline that signal to both innate and adaptive immune cells. Neuro-immune signaling may play a central role in the physiopathology of allergic diseases including atopic dermatitis, asthma and food allergies. Therefore, getting a better understanding of these cellular and molecular neuro-immune interactions could lead to novel therapeutic approaches to treat allergic diseases.

Food allergen labelling: "May contain" evidence from Malaysia

Food allergen labelling is mandatory and regulated whilst precautionary allergen labelling (PAL) remains voluntary in most countries. It is the aim of this study to identify the food allergens declared in food products sold in a developing country and to what extent food allergens and PAL are emphasised in the products. A total of 505 food and beverages (snacks, baked goods, confectionary, baby food, condiments & jams, beverages, powder & paste, instant food, chilled & frozen food and canned food) were evaluated in Malaysia. Soybean represents the largest group of food allergen declared in labels, followed by wheat and milk products. Thirteen variations of contains statement were found with "Contains [allergen(s)]" being the most common (55.02%). There were 22 different types of "may contain" statements with 'May contain traces of [allergen(s)]' being the most common advice labelling used (55.41%). Different font type or emphasis such as brackets (51.57%) and bold font (33.86%) were used to inform consumers about presence of allergens. The national regulations on food allergen labelling are then critically contrasted with other Asian countries and the EU Regulation No. 1169/2011, which represents one of the most stringent food regulations in the world. Improving current allergen labelling limitations and practices would be of great benefit to consumers to prevent risk of food hypersensitivity.