Primary dietary prevention of food allergy

Preparation of Hypoallergenic Whey Protein Hydrolysate by a Mixture of Alcalase and Prozyme and Evaluation of Its Digestibility and Immunoregulatory Properties

Whey protein (WP) has nutritional value, but the presence of β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) cause allergic reactions. In this study, hypoallergenic whey protein hydrolyate (HWPH) was prepared by decomposing β-LG and α-LA of WP using exo- and endo-type proteases. The enzyme mixing ratio and reaction conditions were optimized using response surface methodology (RSM). Degradation of α-LA and β-LG was confirmed through gel electrophoresis, and digestion, and absorption rate, and immunostimulatory response were measured using in vitro and in vivo systems. Through RSM analysis, the optimal hydrolysis conditions for degradation of α-LA and β-LG included a 1:1 mixture of Alcalase and Prozyme reacted for 10 h at a 1.0% enzyme concentration relative to substrate. The molecular weight of HWPH was <5 kDa, and leucine was the prominent free amino acid. Both in vitro and in vivo tests showed that digestibility and intestinal permeability were higher in HWPH than in WP. In BALB/c mice, as compared to WP, HWPH reduced allergic reactions by inducing elevated Type 1/Type 2 helper T cell ratio in the blood, splenocytes, and small intestine. Thus, HWPH may be utilized in a variety of low allergenicity products intended for infants, adults, and the elderly.

Leptin, Obesity Parameters, and Atopy Among Children with Asthma

Leptin, as a major adipokine, positively correlates with the body's fat, while atopy is an important feature in the development of childhood asthma. We aimed to evaluate the relationship between leptin, parameters of obesity, and atopy in children with asthma. The study included 112 children (73 boys, 39 girls, mean age 11.1±2.4). 41 were overweight, 38 had asthma and a normal body mass index (BMI), and 33 were overweight asthmatics. Serum leptin levels, BMI, waist circumference (WC), and waist to hips ratio (WHR) were measured. Skin prick test (SPT)/CAP, total serum IgE, fractional exhaled nitric oxide (FeNO), and pulmonary function tests were performed. In asthmatic children, serum leptin median level was 9.2±16.2 ng/ml, in overweight children was 30.6±21.6 ng/ml, and in overweight asthmatics was 31.1±20.3 ng/ml with a significant difference between the groups (p=0.0374), yet with a significantly lower median level in the group of children with asthma compared to the overweight children: with asthma (p=0.00001) and without asthma (p=0.00001). In the three groups of patients, BMI and WC displayed a significant positive correlation with leptin (for BMI r=0.652 vs. r=0.530 vs. r=0.563, respectively and for WC r=0.508 vs. r=0.426 vs. r=0.527, respectively). No significant correlations of leptin within atopy parameters (Eo, IgE, SPT/CAP, FeNO) in all three analyzed groups (p>0.05) was detected. Conclusion: Atopy was not confirmed as an underlying mechanism of the association between asthma and being overweight. Leptin had a significant linear correlation as a parameter of central obesity with BMI and WC in all three groups, but not with WHR.

Factors influencing the incidence and prevalence of food allergy

Food allergy is an increasing problem in Europe and elsewhere and severe reactions to food are also becoming more common. As food allergy is usually associated with other forms of allergic sensitisation it is likely that many risk factors are common to all forms of allergy. However the potential severity of the disease and the specific public heath measures required for food allergy make it important to identify the specific risk factors for this condition. Food allergy is unusual in that it often manifests itself very early in life and commonly remits with the development of tolerance. Hypotheses that explain the distribution of food allergy include specific genetic polymorphisms, the nature of the allergens involved and the unique exposure to large quantities of allergen through the gut. Progress has been made in developing more specific and testable hypotheses but the evidence for any of these is still only preliminary. Further collaborative research is required to develop an appropriate public health response to this growing problem.

Antiinfective properties of human milk

The unfavorable effects of neonatal immunodeficiency are limited by some naturally occurring compensatory mechanisms, such as the introduction of protective and immunological components of human milk in the infant. Breast-feeding maintains the maternal-fetal immunological link after birth, may favor the transmission of immunocompetence from the mother to her infant, and is considered an important contributory factor to the neonatal immune defense system during a delicate and crucial period for immune development. Several studies have reported that breast-feeding, because of the antimicrobial activity against several viruses, bacteria, and protozoa, may reduce the incidence of infection in infants. The protection from infections may be ensured either passively by factors with antiinfective, hormonal, enzymatic, trophic, and bioactive activity present in breast milk, or through a modulator effect on the neonatal immune system exerted by cells, cytokines, and other immune agents in human milk.

The yin and yang of integrative clinical care, education, and research

Communication between mainstream clinician scientists and complementary therapists is often problematic, in part because of different perspectives, assumptions, and values. However, a simple conceptual model can help conventional scientists and less conventional practitioners find common ground and appreciate their unique approaches toward achieving the same goals. The model described in this article has grown out of my experience in integrating complementary therapies and approaches into clinical care, education, and research. It uses the familiar yin-yang symbol from Chinese medicine to build bridges between mainstream Western clinician-scientists and complementary therapists from other traditions. Over the past seven years, I have developed and used this model in caring for patients, teaching medical students and residents, and conducting research in conjunction with complementary clinicians. This paper describes the yin-yang model as a way to integrate and enhance the understanding of different cultures of healthcare.

Dietary management of food allergy

Food allergy is a modifiable disease, and at present its only form of management is dietary elimination of the offending food or foods. Success depends on the modification of four sources of food-related risk: underestimation of the food allergy problem; ignorance of cross-reacting allergens in other foods; unsupportive or uninformed measures from the family or school environments; and inadequate social recognition that food allergy is a growing public health problem. Ultimately, the empowerment of children with allergies through education, allergist and dietician guidance, and patient association feedback can minimize the morbidity of food allergy and enhance the quality of life of both the child and the family. From a research perspective, studies on the longterm efficacy of the dietary exclusion of specific food allergens are needed. The role of the pediatrician is central in this regard and would be complemented by advice from a nutritionist.

Food allergy and the introduction of solid foods to infants: a consensus document. Adverse Reactions to Foods Committee, American College of Allergy, Asthma and Immunology

OBJECTIVE

To make recommendations based on a critical review of the evidence for the timing of the introduction of solid foods and its possible role in the development of food allergy.

DATA SOURCES

MEDLINE searches using the following search algorithm: [weaning AND infant AND allergy]/[food allergy AND sensitization]/[dietary prevention AND food allergy OR allergens]/[Jan 1980-Feb 2006].

STUDY SELECTION

Using the authors' clinical experience and research expertise, 52 studies were retrieved that satisfied the following conditions: English language, journal impact factor above 1 or scientific society, expert, or institutional publication, and appraisable using the World Health Organization categories of evidence.

RESULTS

Available information suggests that early introduction can increase the risk of food allergy, that avoidance of solids can prevent the development of specific food allergies, that some foods are more allergenic than others, and that some food allergies are more persistent than others.

CONCLUSIONS

Pediatricians and allergists should cautiously individualize the introduction of solids into the infants' diet. With assessed risk of allergy, the optimal age for the introduction of selected supplemental foods should be 6 months, dairy products 12 months, hen's egg 24 months, and peanut, tree nuts, fish, and seafood at least 36 months. For all infants, complementary feeding can be introduced from the sixth month, and egg, peanut, tree nuts, fish, and seafood introduction require caution. Foods should be introduced one at a time in small amounts. Mixed foods containing various food allergens should not be given unless tolerance to every ingredient has been assessed.

Are food intolerances and allergies increasing in immigrant children coming from developing countries ?

There are not available data concerning the occurrence, the clinical features and the environmental risk factors for food intolerances and allergies in immigrant children. The aim of the study was to evaluate rates, distribution, clinical features and environmental risk factors for food intolerances and allergies in immigrant children. Hospital records of 4,130 patients with celiac disease (CD), cow milk protein intolerance (CMPI) and food allergies (FA) diagnosed in 24 Italian Centres from 1999 to 2001 were retrospectively reviewed, comparing immigrant patients with Italian ones. 78/4,130 (1.9%) patients were immigrant: 36/1,917 (1.9%) had CD, 24/1,370 (1.75%) CMPI and 18/843 (2.1%) FA. They were evenly distributed across Italy and their native areas were: East Europe (23/78), Northern Africa (23/78), Southern Asia (14/78), Saharan and Sub-Saharan Africa (9/78), Southern America (4/78), Far East (3/7), Middle East (2/78). Despite differences in their origin, the clinical features of immigrant children were similar to the ones of Italian patients and among each ethnic group. The majority of them were born in Italy (57/78) or have been residing in Italy since several years (19/78). All of them had lost dietary habits of the native countries and had acquired those of the Italian childhood population. Food intolerances and allergies are present also in children coming from developing countries, and paediatricians will need to have a full awareness of them because the number of immigrant children in Italy is quickly increasing. The clinical features of food intolerances and allergies appear the same in each ethnic group, despite differences in races. Sharing of dietary habits with the Italian childhood population seems to be an important environmental risk factor.

Cow's milk allergy: a complex disorder

Cow's milk allergy (CMA) is a complex disorder. Numerous milk proteins have been implicated in allergic responses and most of these have been shown to contain multiple allergenic epitopes. There is considerable heterogeneity amongst allergic individuals for the particular proteins and epitopes to which they react, and to further complicate matters, allergic reactions to cow's milk are driven by more than one immunological mechanism. Finally, the incidence and dominant allergic mechanisms change with age, with IgE-mediated reactions common in infancy and non-IgE-mediated reactions dominating in adults. The complexity of CMA has lead to many public misconceptions about this disorder, including confusion with lactose intolerance and frequent self-misdiagnosis. Indeed, the prevalence of self-diagnosed CMA in the community is 10-fold higher than the clinically proven incidence, suggesting a sizable population is unnecessarily eschewing dairy products. Avoidance of dairy foods, whether for true or perceived CMA, carries with it nutritional consequences and the provision of appropriate nutritional advice is important. In this review, the epidemiology and natural course of CMA is discussed along with our current understanding of its triggers and immunological mechanisms. We examine current strategies for the primary and secondary prevention of allergic sensitization and the ongoing search for effective therapies to ultimately cure CMA.

Possible reasons for lack of effect of allergen avoidance in atopy-prone infants and sensitive asthmatic patients

The basic paradigm that allergen exposure produces atopic sensitization, and that continued exposure leads to clinical asthma throughout the development of airway inflammation and bronchial hyperreactivity has been challenged. However, because it was observed that epidemiological evidence suggests that around 40% of asthma cases are attributable to atopy (even using restrictive criteria), the obvious corollary is that if allergen avoidance begins before the onset of sensitization (primary prevention), then it should be associated with a reduced number of new cases of the disease. However, there are conflicting results regarding the effect of allergen avoidance on primary prevention of atopic sensitization and asthma onset. Instead, more uniform and positive results are available from secondary prevention studies. Secondary prevention obviously is an attractive opportunity for pediatricians who may recognize the patients who might benefit from these interventions simply by screening for food allergy in young children with atopic dermatitis. The conflicting results of tertiary prevention are most frequently observed in adult patients and sometimes result from incomplete avoidance of allergens responsible for the sensitization.

Differences in race, ethnicity, and socioeconomic status in schoolchildren dispensed injectable epinephrine in 3 Massachusetts school districts

BACKGROUND

Published surveys depicting the increase in the incidence of food allergy, especially peanut or tree nut allergy, in children have not reported any differences in race, ethnicity, or socioeconomic status.

OBJECTIVE

To analyze the demographics of schoolchildren with diverse racial, ethnic, and socioeconomic characteristics dispensed injectable epinephrine.

METHODS

School nurses in 44 schools enrolling 21,875 students recorded the characteristics of students dispensed injectable epinephrine in the 2003-2004 school year. Surveyed school districts included 2 affluent suburban districts enrolling 5,855 students (> 92% white) and 1 urban district enrolling 16,020 students (60% nonwhite).

RESULTS

A total of 181 students in all 3 districts were dispensed injectable epinephrine; 118 of these children had peanut or tree nut allergy. Males were more likely to be dispensed injectable epinephrine than females (odds ratio [OR], 1.44; P < .02). Whites were more likely to have been dispensed injectable epinephrine than nonwhites (OR, 4.76; P < .001). Whites were nearly 5 times more likely to be dispensed injectable epinephrine for peanut or tree nut allergy than nonwhites (OR, 4.5; P < .001). Most students (75%) dispensed injectable epinephrine for peanut or tree nut allergy were enrolled in prekindergarten through grade 5 (P < .001). Whites were more likely than nonwhites to be dispensed injectable epinephrine for stinging insect allergy (OR, 8.7; P < .001).

CONCLUSIONS

This study found significant racial, ethnic, and socioeconomic differences in the prevalence of childhood allergic disorders, especially peanut or tree nut allergy, requiring prescribed injectable epinephrine in a school setting. Additional studies are needed to determine whether minority children are being underdiagnosed or undertreated for allergic disorders requiring injectable epinephrine or whether they truly have a lower incidence of such allergic disorders.

Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives

Adverse reactions to food that result in gastrointestinal symptoms are common in the general population; while only a minority of such individuals will have symptoms due to immunologic reactions to foods, gastrointestinal food allergies do exist in both children and adults. These immune reactions are mediated by immunoglobulin E-dependent and -independent mechanisms involving mast cells, eosinophils, and other immune cells, but the complexity of the underlying mechanisms of pathogenesis have yet to be fully defined. Knowledge of the spectrum of adverse reactions to foods that affect the digestive system, including gastrointestinal food allergy, is essential to correctly diagnose and manage the subset of patients with immunologically mediated adverse reactions to foods. Potentially fatal reactions to food necessitate careful instruction and monitoring on the part of health care workers involved in the care of individuals at risk of anaphylaxis. New methods of diagnosis and novel strategies for treatment, including immunologic modulation and the development of hypoallergenic foods, are exciting developments in the field of food allergy.

Diet and the development of atopic disease

PURPOSE OF REVIEW

The present review addresses the current literature regarding the impact of diet and the development of atopic disease. A search of the literature was carried out covering the following topics: diet and nutrition combined with immediate hypersensitivity, atopy, atopic disease, atopic dermatitis, and food allergy.

RECENT FINDINGS

The search results identified a significant contribution in the form of reviews considering this important topic, which ultimately led to the author's recommendation of these reviews to impress upon readers the impact of the atopy triad: atopic dermatitis to allergic rhinitis and asthma.

SUMMARY

A great deal of information exists in the pathomechanisms of atopic disease that will affect the classification of allergic and non-allergic atopic diseases. Increasing data on the genetic, humoral and cellular forms associated with these diseases will provide more clear-cut diagnostic criteria, treatment regimens and a more strict definition of the disease variants.

Dietary treatment of childhood atopic eczema/dermatitis syndrome (AEDS)

OBJECTIVE

This review summarizes the research and clinical evidence in favour of dietary intervention aimed at eliminating allergenic foods in the management of atopic eczema/dermatitis syndrome (AEDS).

DATA SOURCES

The data source was PubMed, using a search algorithm selecting for clinical studies of AEDS, diet therapy and food allergy in all children to October 2003. Also included is a commentary based on the authors' clinical experience in the allergy unit of a university hospital in Italy.

RESULTS

Fourteen prospective studies matched the entry criteria. Diverse trial designs, diagnostic criteria, types of dietary intervention and length of observation periods precluded meta-analytic methods. Allergenic food exclusion claimed efficacy in 13 of the 14 studies and was most useful in infants, in patients with elevated immunoglobulin E levels and/or multiple food sensitization and in patients with a diagnosis of food allergy.

CONCLUSION

Dietary intervention in the form of an elimination diet is efficacious in children with AEDS when a specific diagnosis of food allergy has been made. Diagnostic evaluation of food allergy should be performed in all children with eczema, particularly in younger children and those with severe forms of the disease.

Quoi de neuf dans l’allergie alimentaire en 2003 ?

Food allergies afflict 4-8% of the children and are associated with clinical and familial burdens. The management of food allergy was improved during the last year. Firstly, early diagnosis should lead to early proper treatment. Recommendations were done by the paediatricians group of the EAACI. Diagnosis and outcome of food allergies were improved by the predictive values of in vitro specific IgE testing. The cut-off level permits diagnosis and follow-up of these individual patients. Until newer therapies available, strict food avoidance is needed. Future therapies under investigation include the reduction of IgE by the infusion of anti-IgE antibodies, immunotherapy with mutated proteins or engineered hypoallergenic food. Murine model was developed, and results were encouraging. Intervention efforts must be instituted early in life and primary prevention of food allergy was stated.