Maternal and infant diets for prevention of allergic diseases: understanding menu changes in 2008

Early life microbial exposures and allergy risks: opportunities for prevention

Allergies, including asthma, food allergy and atopic dermatitis, are increasing in prevalence, particularly in westernized countries. Although a detailed mechanistic explanation for this increase is lacking, recent evidence indicates that, in addition to genetic predisposition, lifestyle changes owing to modernization have an important role. Such changes include increased rates of birth by caesarean delivery, increased early use of antibiotics, a westernized diet and the associated development of obesity, and changes in indoor and outdoor lifestyle and activity patterns. Most of these factors directly and indirectly impact the formation of a diverse microbiota, which includes bacterial, viral and fungal components; the microbiota has a leading role in shaping (early) immune responses. This default programme is markedly disturbed under the influence of environmental and lifestyle risk factors. Here, we review the most important allergy risk factors associated with changes in our exposure to the microbial world and the application of this knowledge to allergy prevention strategies.

Assessment of Pediatrician Awareness and Implementation of the Addendum Guidelines for the Prevention of Peanut Allergy in the United States

Importance

The 2017 Addendum Guidelines for the Prevention of Peanut Allergy in the United States recommend that pediatricians assess infant peanut allergy risk and introduce peanut in the diet at age 4 to 6 months. Early introduction has the potential to prevent peanut allergy development.

Objectives

To measure the rates of guideline awareness and implementation and to identify barriers to and factors associated with implementation among US pediatricians.

Design, Setting, and Participants

This population-based study survey used a 29-item electronic survey instrument that was administered to pediatricians practicing across the United States from June 1, 2018, to December 1, 2018. Invitations to complete a survey were emailed to all pediatricians in the American Academy of Pediatrics vendor database. Eligible participants were nonretired US-based pediatricians providing general care to infants aged 12 months or younger.

Main Outcomes and Measures

The primary outcome was the prevalence of guideline implementation, which was measured by 1 survey item about awareness followed by a second item about implementation. Secondary outcomes included identification of guidelines-focused services provided by pediatricians, knowledge of the guidelines (measured with 3 clinical scenarios), barriers to guideline implementation, need for training, and facilitators of guideline implementation.

Results

A total of 1781 pediatricians were eligible to participate and completed the entire survey. Most respondents self-identified as white (1287 [72.5%]) and female (1210 [67.4%]) individuals. Overall, 1725 (93.4%; 95% CI, 92.2%-94.5%) pediatricians reported being aware of the guidelines. Of those pediatricians who had knowledge of the guidelines, 497 (28.9%; 95% CI, 26.8%-31.1%) reported full implementation and 1105 (64.3%; 95% CI, 62.0%-66.6%) reported partial implementation. Common barriers to implementation included parental concerns about allergic reactions (reported by 575 respondents [36.6%; 95% CI, 34.3%-39.1%]), uncertainty in understanding and correctly applying the guidelines (reported by 521 respondents [33.2%; 95% CI, 30.9%-35.6%]), and conducting in-office supervised feedings (reported by 509 respondents [32.4%; 95% CI, 30.1%-34.8%]). Many pediatricians (1175 [68.4%; 95% CI, 66.1%-70.5%]) reported a need for further training on the guidelines.

Conclusions and Relevance

This survey found that most pediatrician respondents appeared to know of the 2017 guidelines, but less than one-third of respondents reported full implementation. Results of this study may inform future efforts to eliminate barriers to guideline implementation and adherence, thereby reducing the incidence of peanut allergy in infants.

Relationship between respiratory and food allergy and evaluation of preventive measures

Food allergy and respiratory allergy are two frequently associated diseases and with an increasing prevalence. Several reports show the presence of respiratory symptoms in patients with food allergy, while certain foods may be related to the development or exacerbation of allergic rhinitis and asthma. The present update focuses on this relationship, revealing a pathogenic and clinical association between food and respiratory allergy. This association is even more intense when the food hypersensitivity is persistent or starts in the early years of life. Food allergy usually precedes respiratory allergy and may be a risk factor for allergic rhinitis and asthma, becoming a relevant clinical marker for severe atopic asthma. Furthermore, the presence of co-existing asthma may enhance life-threatening symptoms occurring during a food allergic reaction. Recommendations for dietary restrictions during pregnancy and breastfeeding to prevent the development of respiratory allergy are controversial and not supported by consistent scientific data. Current recommendations from medical societies propose exclusive breastfeeding during the first four months of life, with the introduction of solid food in the fourth to the seventh month period of life. A delayed introduction of solid food after this period may increase the risk of developing subsequent allergic conditions. Further studies are encouraged to avoid unjustified recommendations involving useless dietary restrictions.

Dietary pattern and nutrient intake of korean children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is characterized by itching and eczema-like skin lesions, and its symptoms alleviate with age. Recently, the prevalence of AD has increased among adolescents and adults. The increasing prevalence of AD seems to be related to westernized lifestyles and dietary patterns.

OBJECTIVE

The aim of this study was to evaluate the dietary patterns and nutrient intake of patients with AD.

METHODS

The study population consisted of 50 children with AD who visited the Department of Dermatology at Kangnam Sacred Heart Hospital, Seoul, Korea from May 2008 to May 2009. Physical condition and calorie intake were evaluated using the Eczema Area and Severity Index score and Food Record Questionnaire completed by the subjects, and the data were analyzed using the Nutritional Assessment Program Can-pro 3.0 (The Korean Nutrition Society, 2005) program to determine the gap between the actual ingestion and average requirements of 3 major nutrients (i.e. carbohydrates, proteins, and lipids), vitamins (i.e. A, B, C, and E), niacin, folic acid, calcium, iron, phosphorus, and zinc in all subjects.

RESULTS

The intake rate of proteins was 18.02% (recommended dietary allowance [RDA], 7%~20%), of carbohydrates was 67.7% (RDA, 55%~70%), and of lipids was 14.24% (RDA, 15%~30%). Thirty-one subjects (62%) showed deficiency of folic acid, and 21 subjects (42%), of iron supplements.

CONCLUSION

Essential nutrient intake tends to be lower in AD patients than in healthy subjects, and this low intake is closely related to the severity of AD.

Understanding the evidence for and against the role of breastfeeding in allergy prevention

The relationship between breastfeeding and allergic disease risk has been controversial. This article reviews the current evidence for the role of breastfeeding in the prevention of allergic disease. We found considerable methodological limitations inherent in most studies evaluating the effect of breastfeeding in allergic disease. Nevertheless, since randomized control trials in breast feeding research would be considered unethical, the evidence remains limited to poorer quality observational studies where participation and recall bias can severely affect the objectivity of the data collected. Furthermore, reporting of type of breastfeeding (exclusive, full or partial) may be biased by a participant's inherent belief system of what they think they should be doing. Current evidence is inconclusive regarding the effect of breastfeeding on the development of eczema, with the most recent systemic review reporting no protective effect. There is insufficient data regarding the effects of breastfeeding on objective measures of food allergy at any age. Studies show a paradoxical effect of breastfeeding on the prevention of asthma, with an apparent protective effect against early wheezing illness in the first years of life yet an increased risk of asthma in later life; however, these findings must be interpreted with caution. Existing studies fail to adequately adjust for confounders, including the critical issues of protection against early life respiratory illnesses and reverse causation. Therefore, it is possible that the effect of breastfeeding on early wheezing illness reflects protection against respiratory infection, the predominant trigger of wheezing in early childhood, rather than a true reduction in risk of asthma. In summary, future research that takes into account the potential contribution of confounding factors and effect modifiers is needed to clarify the role of breastfeeding in development of allergic disease and to inform current clinical guidelines on the prevention of allergic disease.

Food allergy: present and future management

Food allergy poses a significant burden on patients, families, health care providers, and the medical system. The increased prevalence of food allergy has brought about investigation as to its cause and new treatments. Currently, the only treatment available is to avoid the food and symptomatically treat any reactions. There are multiple clinical and murine models of food allergy treatment that use allergen specific and nonspecific pathways. Allergen specific treatments use mucosal antigen exposure as a method of inducing desensitization and tolerance. Allergen nonspecific methods act via a more global T_H2 suppressive mechanism and may be useful for those patients with multiple food allergies.

Partially hydrolyzed cow's milk formula has a therapeutic effect on the infants with mild to moderate atopic dermatitis: a randomized, double-blind study

OBJECTIVE

The allergy-preventing effect of partially hydrolyzed cow's milk formula (phCMF) in infants at high risk of atopic dermatitis (AD) has been demonstrated in many studies. However, the therapeutic potential of phCMF in treating the infants with AD has not been reported. We sought to assess such therapeutic efficacy of phCMF in infants with mild to moderate AD.

METHODS

From 2006 to 2008, 113 infants <6 months of age with AD were randomized to receive either partially hydrolyzed cow's milk formula (phCMF) or conventional cow's milk formula (CMF) in a double-blind clinical trial. Assessments were made at enrollment and at weeks 4, 8, and 12. The severity of AD was assessed using two scoring systems: Standard guideline for management (diagnosis, severity scoring, and therapy) of AD by the Japanese Dermatological Association Scoring System (JDASS) and the SCORing Atopic Dermatitis (SCORAD). Growth status of the infants was evaluated. Allergy profile was assessed by measuring total blood eosinophils (EOS), total/specific IgE, Th1/Th2 cytokine profiles, and the percentage of regulatory T cells.

RESULTS

After follow-up for 12 wk, 27 infants (23.89%) dropped off study. Analysis was performed on 86 infants by the end of 12-wk observation. The AD severity scores were significantly reduced in the phCMF group (n = 56) compared with CMF group (n = 30) after 12 wk (p < 0.05). The severity scores of phCMF group were significantly reduced at weeks 4, 8, and 12 compared to enrollment (p < 0.05). In contrast, no significant improvement was observed for CMF group at any of those time points (p > 0.05). The number of AD flare-ups was significantly decreased in the phCMF group (p = 0.002). Th1/Th2 ratio in phCMF was significantly increased compared with CMF group (p = 0.041). The growth rates did not differ significantly between these feeding groups at any assessed time point (p > 0.05) and were in the normal range.

CONCLUSION

This study suggests a novel therapeutic effect of phCMF in treating infants with mild to moderate AD during the first 6 months of their life without affecting their nutritional status.

Maternal nutrition and perinatal outcomes

Diet and patterns of eating during pregnancy can affect perinatal outcomes through direct physiologic effects or by stressing the fetus in ways that permanently affect phenotype. Supplements are not a magic nutritional remedy, and evidence of profound benefit for most supplements remains inconclusive. However, research supports calcium supplements to decrease preeclampsia. Following a low glycemic, Mediterranean-type diet appears to improve ovulatory infertility, decrease preterm birth, and decrease the risk of gestational diabetes. Although women in the United States have adequate levels of most nutrients, subpopulations are low in vitamin D, folate, and iodine. Vitamin D has increasingly been shown to be important not only for bone health, but also for glucose regulation, immune function, and good uterine contractility in labor. To ensure adequate vitamin and micronutrient intake, especially of folate before conception, all reproductive age women should take a multivitamin daily. In pregnancy, health care providers need to assess women's diets, give them weight gain recommendations based on their body mass index measurement, and advise them to eat a Mediterranean diet rich in omega-3 fatty acids (ingested as low-mercury risk fatty fish or supplements), ingest adequate calcium, and achieve adequate vitamin D levels through sun exposure or supplements. Health care providers should continue to spend time on nutrition assessment and counseling.

Food allergy and atopic dermatitis: separating fact from fiction

The relationship between food and atopic dermatitis (AD) is complex. A common misunderstanding is that food allergies have a significant impact on the course of AD, resulting in uncontrolled attempts at elimination diets and undertreatment of the skin itself. Studies have shown that only a small portion of cutaneous reactions to food in the form of late, eczematous eruptions will directly exacerbate AD in young infants who have moderate-to-severe AD. Given the low frequency of food allergies actually inducing flares of AD, the focus should return to appropriate skin therapy, and identification of true food allergies should be reserved for recalcitrant AD in children in whom the suspicion for food allergy is high. A different relationship between food and AD involves delaying or preventing AD in high-risk infants by exclusive breastfeeding during the first 4 months of life. Finally, the skin barrier defect in AD may allow for easier and earlier sensitization of food and airborne allergens; therefore, exposure of food proteins on AD skin may act as a risk factor for development of food allergies.

Food allergy: separating the science from the mythology

Numerous genes are involved in innate and adaptive immunity and these have been modified over millions of years. During this evolution, the mucosal immune system has developed two anti-inflammatory strategies: immune exclusion by the use of secretory antibodies to control epithelial colonization of microorganisms and to inhibit the penetration of potentially harmful agents; and immunosuppression to counteract local and peripheral hypersensitivity against innocuous antigens, such as food proteins. The latter strategy is called oral tolerance when induced via the gut. Homeostatic mechanisms also dampen immune responses to commensal bacteria. The mucosal epithelial barrier and immunoregulatory network are poorly developed in newborns. The perinatal period is, therefore, critical with regard to the induction of food allergy. The development of immune homeostasis depends on windows of opportunity during which innate and adaptive immunity are coordinated by antigen-presenting cells. The function of these cells is not only orchestrated by microbial products but also by dietary constituents, including vitamin A and lipids, such as polyunsaturated omega-3 fatty acids. These factors may in various ways exert beneficial effects on the immunophenotype of the infant. The same is true for breast milk, which provides immune-inducing factors and secretory immunoglobulin A, which reinforces the gut epithelial barrier. It is not easy to dissect the immunoregulatory network and identify variables that lead to food allergy. This Review discusses efforts to this end and outlines the scientific basis for future food allergy prevention.

Science base of complementary feeding practice in infancy

PURPOSE OF REVIEW

The review presents a selection of publications on complementary feeding in industrialized countries during 2008-2009, after the publication of the ESPGHAN position paper in early 2008.

RECENT FINDINGS

The WHO recommendation for introduction of complementary feeding at 6 months is adapted in many countries, but the issue is still discussed and many mothers introduce complementary feeding as early as before 4 months. The European Food Safety Authority recently published a comprehensive review on the appropriate age for the introduction of complementary feeding and concluded that introduction between 4 and 6 months is safe. One study showed that delaying introduction of complementary feeding up to 6 months resulted in lower risk of overweight as adult. Milk protein is stimulating insulin-like growth factor-1 and growth and a recent study supports a long-term programming of the insulin-like growth factor-1 axis. There is now a broad consensus that there is no need to delay the introduction of hyperallergenic foods, which might even increase the risk of allergic disease. Randomized studies show that docosahexaenoic acid may affect heart rate and thereby cardiovascular regulation.

SUMMARY

Despite some recent interesting publications, there is still a need for more large randomized studies to further explore to what degree the time of introduction and composition of complementary foods have effects on growth, development and especially the long-term risk of diseases.

Peanut sensitisation and allergy: influence of early life exposure to peanuts

The aim of the present systematic review was to evaluate the influence of early life exposure (maternal and childhood) to peanuts and the subsequent development of sensitisation or allergy to peanuts during childhood. Studies were identified using electronic databases and bibliography searches. Studies that assessed the impact of non-avoidance compared with avoidance or reduced quantities of peanuts or peanut products on either sensitisation or allergy to peanuts, or both outcomes, were eligible. Six human studies were identified: two randomised controlled trials, two case-control studies and two cross-sectional studies. In addition, published animal and mechanistic studies, relevant to the question of whether early life exposure to peanuts affects the subsequent development of peanut sensitisation, were reviewed narratively. Overall, the evidence reviewed was heterogeneous, and was limited in quality, for example, through lack of adjustment for potentially confounding factors. The nature of the evidence has therefore hindered the development of definitive conclusions. The systematic review of human studies and narrative expert-led reviews of animal studies do not provide clear evidence to suggest that either maternal exposure, or early or delayed introduction of peanuts in the diets of children, has an impact upon subsequent development of sensitisation or allergy to peanuts. Results from some animal studies (and limited evidence from human subjects) suggest that the dose of peanuts is an important mediator of peanut sensitisation and tolerance; low doses tend to lead to sensitisation and higher doses tend to lead to tolerance.

Gastrointestinal manifestations of food allergy

Gastrointestinal food allergies are not rare in infants and children. Symptoms include vomiting, reflux, abdominal pains, diarrhea and constipation. Clinical diagnosis requires the exclusion of nonimmunologic diseases that have similar gastrointestinal symptoms. In food allergy, the immune reactions involved can be immunoglobulin (Ig)E-mediated, cell-mediated or both. Symptoms in other target organs are common in cases of IgE-mediated disorders, but not in the cell-mediated disorders in which symptoms are usually localized to the gut. Diagnosis utilizes detailed medical history, clinical evaluation, skin testing, food-specific IgE antibodies, responses to elimination diet and oral food challenges. Endoscopic biopsies are essential in cell-mediated disorders and allergic eosinophilic gastropathies. Treatment includes avoidance of the offending food by a restriction diet in children and the use of hydrolyzed or amino acid-based formulas in young infants. Topical and/or systemic corticosteroids can also be used in eosinophilic esophagitis. Current research is aimed at improving the diagnostic tools and therapeutic options available to patients.

Update on allergies in pregnancy, lactation, and early childhood

The factors responsible for the induction of allergic disease at an early age have not been completely identified. Therefore a major research focus is their identification to elaborate recommendations for prevention of sensitization in high-risk or atopic children. This review analyzes known or suspected reasons for sensitization in pregnant women and infants from both clinical and experimental animal studies. Recent studies and meta-analyses could not confirm the protective effect of an allergen-poor diet on the part of the mother during pregnancy and lactation. Likewise, the type of bottle feeding or the introduction of solid food into the child's diet might not significantly influence the development of atopy, allergy, or asthma in the child's life. Disappointingly, the few preventive measures remaining to reduce the risk of allergic sensitization and atopic diseases in mother and child are the avoidance of smoking and alcohol consumption during pregnancy and lactation and the avoidance of the impairment of gastric function. Further studies are urgently needed to address the influence of certain foods and nutrients, as well as environmental factors, for prevention of allergic diseases in the low- or high-risk infant.

Advances in pediatric asthma in 2008: where do we go now?

This year's summary focuses on recent advances in pediatric asthma as reported in Journal publications in 2008. New National Asthma Education and Prevention Program asthma guidelines were released in 2007 with a special emphasis on asthma control. Attention was redirected to methods that could reduce impairment, specifically symptom control, and minimize risk, including exacerbations. Journal theme issues in 2008 focused on several relevant asthma topics including asthma exacerbations, exercise-induced bronchospasm, asthma and obesity, and occupational asthma. This review highlights Journal articles and related articles that reinforce principles of the guidelines and also direct us to new information that will advance asthma care for children. A major step forward will be finding ways to implement the asthma guidelines.

American Academy of Pediatrics recommendations on the effects of early nutritional interventions on the development of atopic disease

PURPOSE OF REVIEW

To review the American Academy of Pediatrics statement on the effects of early nutritional interventions on the development of atopic disease in infants and children.

RECENT FINDINGS

Recent findings suggest that restriction of maternal diet during pregnancy and lactation does not play a major role in the development of allergic disease. In high-risk infants, exclusive breastfeeding for at least 4 months prevents or delays atopic dermatitis, cow milk allergy, and wheezing early in life. There is evidence that supplementing breastfeeding with a hydrolyzed formula protects against atopic disease, especially atopic dermatitis in at-risk infants. Finally, there is little evidence that delaying the introduction of complementary foods beyond 4-6 months of age has any protective effect against allergy. There is insufficient data that any dietary intervention beyond 4-6 months of age has any protective effect against developing atopic disease.

SUMMARY

In high-risk infants, there is evidence that exclusive breastfeeding for at least 4 months, and delaying of complementary foods until 4-6 months, prevent the development of allergy. There is some evidence that supplementing hydrolyzed formulas in high-risk infants may delay or prevent allergic disease. There is no convincing evidence that maternal manipulation of diet during pregnancy or lactation, use of soy products, or infant dietary restrictions beyond 4-6 months has any effect on the development of atopic disease.

[What's new in pediatric dermatology?]

The main selected articles in pediatric dermatology covered the following topics: development and maturation of the epidermal barrier in the neonate, iatrogenic events in the neonatal ICU, diagnostic value of minor birthmarks, complications, risk factors and treatment of hemangiomas, coagulopathy in venous malformations, epidemiology and dermoscopy of congenital and acquired melanocytic nevi in childhood, growth of the body surface area, new pathogenic concepts and treatment in atopic dermatitis, the impact of filaggrin deficiency, hereditary factors in Kawasaki disease, severe and drug resistant cases, management of juvenile dermatomyositis, treatment of childhood psoriasis with biologics, the new classification of epidermolysis bullosa and therapeutic approach with cell therapy, neurological impairment in xeroderma pigmentosum, behavioural anomalies in X-linked ichthyosis, guidelines for neurofibromatosis type I, the genetics of an hereditary hypotrichosis, infantile acne, rosacea in childhood, mast cell disease management and, last but not least, treatment of hair lice with silicone.

Prenatal maternal diet affects asthma risk in offspring

Recently, epigenetic-mediated mechanisms - which involve heritable changes in gene expression in the absence of alterations in DNA sequences - have been proposed as contributing to asthma. In this issue of the JCI, Hollingsworth and colleagues report on the effect of prenatal maternal dietary intake of methyl donors on the risk of allergic airway disease in offspring in mice and show that these effects involve epigenetic regulation (see the related article beginning on page 3462). Supplementation of the maternal diet with methyl donors was associated with greater airway allergic inflammation and IgE production in F1 and, to some extent, F2 progeny. Site-specific differences in DNA methylation and reduced transcriptional activity were detected. If these findings are confirmed, a new paradigm for asthma pathogenesis may be emerging.