Food allergy and additives: triggers in asthma

Clinical implications of asthma endotypes and phenotypes

Background: Asthma is a complex disorder with variable clinical expression. Recognizable clinical and laboratory features define phenotypes, and specific biologic pathways define endotypes. Identifying the specific pathway responsible for persistent asthma would enable the clinician to select the optimal inhibitors, which currently are biologic therapies. Objective: To provide an up-to-date review of the current clinical status of endotype and phenotype characterizations of asthma and discuss these categories in relation to the available, or likely available, biologic therapies for asthma. Methods: The medical literature was reviewed based on the search terms: asthma biologics, severe asthma, uncontrolled asthma, corticosteroid-dependent asthma, phenotype, endotype, and type 2. We also used our knowledge of the literature and current research. Results: All of the current biologics, including the recently approved tezepelumab, were most effective with increased type 2 biomarkers, which identify exacerbation-prone asthma. Current biomarkers do not permit consistent identification of specific endotypes to facilitate informed selection of the optimal therapy for an individual patient. Thus, empiricism and the art of care continue to play major roles in treatment selection. Conclusion: Current biologic therapies for asthma and those likely to be U.S. Food and Drug Administration approved within the near future work best in subjects with strong type 2 signatures. Available biomarkers and observable characteristics do not enable clinicians to recognize specific endotypes, but rather subphenotypes or overlapping endotypes. The goal of identifying the optimal patient for a specific therapy remains elusive, but worthy of pursuit. In the interim, the availability of an increasing number of treatment options allows the clinician to help most of his or her patients.

A medical nutrition therapy primer for childhood asthma: current and emerging perspectives

Asthma is the most common chronic disease in children. Prevalence has increased in the past 2 decades and has reached a plateau of approximately 9% of children in the United States, affecting about 6.7 million children. The increased prevalence of childhood asthma has paralleled the increased prevalence in childhood obesity. Changes in diet have also been implicated in the increased prevalence of asthma, among other risk factors. The main symptoms of asthma (ie, wheezing, coughing, and chest tightness) require medical evaluation and monitoring. The cornerstone of asthma management is medication therapy, frequently consisting of inhaled bronchodilators and corticosteroids and, when needed, therapy of corticosteroids by mouth. As part of the multidisciplinary management of this chronic disease, nutrition assessment and follow-up in childhood asthma is necessary to identify and address relevant nutrition-related problems. These problems can involve food-medication interactions, obesity, gastroesophageal reflux disease, food allergies, and other issues; therefore, individualized medical nutrition therapy is warranted. Finally, counseling to achieve a healthy balanced diet is recommended for overall health and weight management. A recent but small number of descriptive investigations agree that adherence to a Mediterranean dietary pattern can be associated with a decreased risk of current asthma symptoms in children. Although this evidence is promising, food interventions are required to substantiate an evidence-based foundation for medical nutrition therapy in childhood asthma. At this time, there is no known health risk if a Mediterranean diet is adopted.

Diagnosis and Rationale for Action Against Cow's Milk Allergy (DRACMA): a summary report

The 2nd Milan Meeting on Adverse Reactions to Bovine Proteins was the venue for the presentation of the first consensus-based approach to the management of cow's milk allergy. It was also the first time that the Grading of Recommendations, Assessments, Development, and Evaluation approach for formulating guidelines and recommendations was applied to the field of food allergy. In this report we present the contributions in allergen science, epidemiology, natural history, evidence-based diagnosis, and therapy synthesized in the World Allergy Organization Diagnosis and Rationale for Action against Cow's Milk Allergy guidelines and presented during the meeting. A consensus emerged between discussants that cow's milk allergy management should reflect not only basic research but also a newer and better appraisal of the literature in the light of the values and preferences shared by patients and their caregivers in partnership. In the field of diagnosis, atopy patch testing and microarray technology have not yet evolved for use outside the research setting. With foreseeable breakthroughs (eg, immunotherapy and molecular diagnosis) in the offing, the step ahead in leadership can only stem from a worldwide organization implementing consensus-based clinical practice guidelines to diffuse and share clinical knowledge.

Bronchial reactivity in schoolchildren allergic to food

BACKGROUND

Food allergy (FA) is associated with an increased risk of asthma.

OBJECTIVE

To evaluate whether bronchial hyperreactivity (BHR) occurs in children with FA depending on the presence of respiratory symptoms.

METHODS

Fifty-four children with FA and 62 without FA were studied for BHR, defined as a provocation concentration of methacholine that caused a decrease in forced expiratory volume in 1 second of 20% (PC20). The diagnosis of FA was established using questionnaires, clinical criteria, skin prick tests, serum specific IgE antibodies, and a double-blind placebo-controlled food challenge.

RESULTS

Among nonasthmatic children, BHR was diagnosed in 15 (47%) with FA and in 7 (17%) without FA (P < .005); BHR was demonstrated in 7 children (41%) with FA alone. All the patients with asthma with or without FA had BHR. The mean (SD) PC20 in children with FA alone was 2.8 [1.38] mg/mL and was significantly higher than that in children with asthma alone (0.88 [1.01] mg/mL) or with asthma and FA (0.96 [0.83] mg/mL) (P < .001). BHR was detected in 5 children (36%) with a mild anaphylactic reaction provoked by food, in 23 (74%) with a moderate reaction, and in all the children with a severe reaction.

CONCLUSIONS

Children with FA had increased BHR independent of respiratory symptoms. Although BHR occurs in asymptomatic children with FA, its course is milder than that in children with FA and asthma. Factors that determine BHR prevalence in children with FA are similar to those in children without FA.

Glutamate. Its applications in food and contribution to health

This article reviews application of glutamate in food and its benefits and role as one of the common food ingredients used. Monosodium glutamate is one of the most abundant naturally occurring amino acids which frequently added as a flavor enhancer. It produced a unique taste that cannot be provided by other basic taste (saltiness, sourness, sweetness and bitterness), referred to as a fifth taste (umami). Glutamate serves some functions in the body as well, serving as an energy source for certain tissues and as a substrate for glutathione synthesis. Glutamate has the potential to enhance food intake in older individuals and dietary free glutamate evoked a visceral sensation from the stomach, intestine and portal vein. Small quantities of glutamate used in combination with a reduced amount of table salt during food preparation allow for far less salt to be used during and after cooking. Because glutamate is one of the most intensely studied food ingredients in the food supply and has been found safe, the Joint Expert Committee on Food Additives of the United Nations Food and Agriculture Organization and World Health Organization placed it in the safest category for food additives. Despite a widespread belief that glutamate can elicit asthma, migraine headache and Chinese Restaurant Syndrome (CRS), there are no consistent clinical data to support this claim. In addition, findings from the literature indicate that there is no consistent evidence to suggest that individuals may be uniquely sensitive to glutamate.

Food Intolerance and childhood asthma: what is the link?

Food allergies and asthma are increasing worldwide. It is estimated that approximately 8% of children aged <3 years have food allergies. Foods can induce a variety of IgE-mediated, cutaneous, gastrointestinal, and respiratory reactions. The most common foods responsible for allergic reactions in children are egg, milk, peanut, soy, fish, shellfish, and tree nuts. Asthma alone as a manifestation of a food allergy is rare and atypical. Less than 5% of patients experience wheezing without cutaneous or gastrointestinal symptoms during a food challenge. In addition to acute respiratory symptoms, a food allergy may also induce airway hyper-responsiveness beyond the initial reaction. This process can occur in patients who do not demonstrate a decrease in lung function during the reaction. Inhalation of aerosolized food particles can cause respiratory symptoms in selected food-allergic individuals, particularly with fish and shellfish during cooking and aerosolization. However, this has not been demonstrated with the smelling of, or casual contact with, peanut butter. Rarely, food additives such as sulfating agents can cause respiratory reactions. This reaction occurs primarily in patients with underlying asthma, particularly in patients with more severe asthma. In contrast, there is no convincing evidence that tartrazine or monosodium glutamate can induce asthma responses. Although food-induced asthma is rare, it is common for patients and clinicians to perceive that food can trigger asthma. Avoidance of specific foods or additives has not been shown to improve asthma, even in patients who may perceive that a particular food worsens their asthma.However, patients with underlying asthma are more likely to experience a fatal or near-fatal food reaction. Food reactions tend to be more severe or life threatening when they involve the respiratory tract. The presence of a food allergy is a risk factor for the future development of asthma, particularly for children with sensitization to egg protein. The diagnosis of a food allergy includes skin or in vitro testing as an initial study when the history suggests food allergy. While negative testing generally rules out a food allergy, positive testing should be followed by a food-challenge procedure for a definitive diagnosis. The CAP-RAST FEIA (CAP-radioallergosorbent test [RAST] fluoroenzyme immunoasssay system [FEIA]) is an improved in vitro measure that in some cases may decrease the need for food challenges. However, similar to skin testing and the RAST, there is good sensitivity but poor specificity, such that specific challenges are often warranted.

Assessing the Potential to Induce Respiratory Hypersensitivity

Acute and repeat dose inhalation studies have been an important part of the safety assessment of drugs, chemicals, and other products throughout the world for many years. It is known that damage to the respiratory tract can be triggered either by nonspecific irritation or by specific immune-mediated pathogenesis, and it is acknowledged that traditional inhalation studies are not designed to address fully the impact of the latter. It is also recognized that different types of immune-mediated responses can be triggered by different classes of compounds and that some immune reactions in the lung are life threatening. As such, it is important to understand as fully as possible the basis for the immune-mediated damage to the lung in order to characterize adequately the risks of individual chemicals or proteins. It is against this background that a review of the methods used to assess the potential for immune-mediated respiratory hypersensitivity was conducted. The primary objectives of this review are to discuss appropriate methods for identifying and characterizing respiratory hypersensitivity hazards and risks; and to identify key data gaps and related research needs with respect to respiratory hypersensitivity testing. The following working definition of respiratory hypersensitivity was formulated: a hypersensitivity response in the respiratory tract precipitated by a specific immune response, mediated by multiple mechanisms, including IgE antibody. Because of the importance played by various classes of compounds, the subsequent sections of this review will consider protein-specific, chemical-specific, and drug-specific aspects of respiratory hypersensitivity.