Dietary prevention of allergic disease in children: are current recommendations really based on good evidence?

The German Infant Nutritional Intervention Study (GINI) for the preventive effect of hydrolyzed infant formulas in infants at high risk for allergic diseases. Design and selected results

In the complex interaction between certain environmental factors and genetic disposition, the early allergen exposure plays a major role in the development of allergic diseases. In aiming to reduce the allergen burden for the infant at risk during early infancy, cow's milk protein hydrolysate infant formulas (hypoallergenic infant formulas) are appropriate alternatives to breastfeeding for primary allergy prevention. The German Infant Nutritional Intervention-Program (GINI) was supported for the first 3 years by the German Ministry for Education and Research (BMBF) (FKZ 01 EE 9401-4). It is a birth cohort which was primarily scheduled until the children were 3 years old. The aim of the prospective, randomized, double-blind intervention study was to investigate the impact of different cow's milk protein hydrolysate infant formulas in the first 4 - 6 months on the development of allergic diseases in children at risk due to at least one parent or biological sibling with a history of allergic disease. The allocation to one of the 4 intervention formulas (partial whey hydrolysate, extensive whey hydrolysate, extensive casein hydrolysate or standard cow's milk formula) was randomised and stratified by family history (single/biparental) and the respective obstetric clinic. Recruitment was carried out by the three clinical centers (Research Institute Marien-Hospital Wesel, Children's Department, Ludwigs-Maximilians-University Munich and Children's Department Technical University Munich) in 18 obstetric clinics between 01.09.1995 and 30.06.1998. Along with the intervention study a non-interventional, complementary observational cohort of children with or without allergy risk was recruited and followed by annual self-reporting parental questionnaires. The GINI intervention study (GINI-I, N = 2.252) and the non-interventional observation study (GINI-NI, N = 3.739) are combined in the population-based GINIplus study (see article J. Heinrich et al. in this journal). The results of the GINI intervention study confirm that, cow's milk protein hydrolysate infant formulas have a preventive effect on allergic manifestation compared with a standard cow's milk formula, until school age. However, the dimension of the effect is different between the formulas. This effect, which is mainly driven by the effect on atopic eczema, develops in the first months of life and persists without rebound. In the formula groups the cumulative incidence of atopic eczema until school age is reduced between 26% and 45% compared with standard cow's milk formula. A beneficial effect of the hydrolysate formulas on the respiratory manifestations asthma and rhinoconjunctivitis, however, could not be shown. By comparing the GINI intervention and non-intervention arm of the GINIplus study it was demonstrated, that a family history for allergy doubles the risk for eczema in the offspring. Early intervention with cow's milk protein hydrolysate infant formulas is able to substantially compensate this risk for eczema until the age of 6 years. In contrast, by randomization to standard cow's milk formula this risk showed a trend towards a higher incidence compared with children at risk from the non-intervention group. Thus, the results of the GINIplus study have contributed to answer some of the controversially discussed questions.

Allergic manifestation 15 years after early intervention with hydrolyzed formulas--the GINI Study

Background

Data on the long‐term impact of hydrolyzed formulas on allergies are scarce.

Objective

To assess the association between early intervention with hydrolyzed formulas in high‐risk children and allergic outcomes in adolescence.

Methods

GINI trial participants (n = 2252) received one of four formulas in the first four months of life as breastmilk substitute if necessary: partial or extensive whey hydrolyzate (pHF‐W, eHF‐W), extensive casein hydrolyzate (eHF‐C) or standard cow′s milk formula (CMF) as reference. Associations between these formulas and the cumulative incidence and prevalence of parent‐reported physician‐diagnosed asthma, allergic rhinitis (AR) and eczema, as well as spirometric indices and sensitization, were examined using generalized linear models.

Results

Between 11 and 15 years, the prevalence of asthma was reduced in the eHF‐C group compared to CMF (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.26–0.89), which is consistent with the spirometric results. The cumulative incidence of AR was lower in eHF‐C (risk ratio (RR) 0.77, 95% CI 0.59–0.99]) and the AR prevalence in pHF‐W (OR 0.67, 95% CI 0.47–0.95) and eHF‐C (OR 0.59, 95% CI 0.41–0.84). The cumulative incidence of eczema was reduced in pHF‐W (RR 0.75, 95% CI 0.59–0.96) and eHF‐C (RR 0.60, 95% CI 0.46–0.77), as was the eczema prevalence between 11 and 15 years in eHF‐C (OR 0.42, 95% CI 0.23–0.79). No significant effects were found in the eHF‐W group on any manifestation,nor was there an effect on sensitization with any formula.

Conclusion

In high‐risk children, early intervention using different hydrolyzed formulas has variable preventative effects on asthma, allergic rhinitis and eczema up to adolescence.

Allergies in high-risk schoolchildren after early intervention with cow's milk protein hydrolysates: 10-year results from the German Infant Nutritional Intervention (GINI) study

BACKGROUND

The long-term effect of nutritional intervention with hydrolysate infant formulas on allergic manifestations in high-risk children is uncertain.

OBJECTIVE

We sought to investigate the effect of hydrolysate infant formulas on allergic phenotypes in children with family history of allergies at school age.

METHODS

We analyzed data from participants of the prospective German Infant Nutritional Intervention study after 10 years of follow-up. At birth, children were randomly assigned to receive, for the first 4 months, one of 4 blinded formulas as breast milk substitute, if necessary: partially hydrolyzed whey formula (pHF-W), extensively hydrolyzed whey formula (eHF-W), extensively hydrolyzed casein formula (eHF-C), or standard cow's milk formula. Outcomes were parent-reported, physician-diagnosed allergic diseases. Log-binomial regression models were used for statistical analysis.

RESULTS

The relative risk for the cumulative incidence of any allergic disease in the intention-to-treat analysis (n = 2252) was 0.87 (95% CI, 0.77-0.99) for pHF-W, 0.94 (95% CI, 0.83-1.07) for eHF-W, and 0.83 (95% CI, 0.72-0.95) for eHF-C compared with standard cow's milk formula. The corresponding figures for atopic eczema/dermatits (AD) were 0.82 (95% CI, 0.68-1.00), 0.91 (95% CI, 0.76-1.10), and 0.72 (95% CI, 0.58-0.88), respectively. In the per-protocol analysis (n = 988) effects were stronger. The period prevalence of AD at 7 to 10 years was significantly reduced with eHF-C in this analysis, but there was no preventive effect on asthma or allergic rhinitis.

CONCLUSION

The significant preventive effect on the cumulative incidence of allergic diseases, particularly AD, with pHF-W and eHF-C persisted until 10 years without rebound, whereas eHF-W showed no significant risk reduction. There is insufficient evidence of ongoing preventive activity at 7 to 10 years of age.

Partially hydrolyzed 100% whey protein infant formula and reduced risk of atopic dermatitis: a meta-analysis

OBJECTIVE

A reduced risk of atopic dermatitis (AD) among healthy infants who received 100% whey protein partially hydrolyzed formula (PHF-W) compared with intact protein cow's milk formula (CMF), has been reported in several studies. To validate these observations and estimate the magnitude of this potential association with greater statistical precision, we conducted a meta-analysis of clinical trial and intervention studies.

MATERIALS AND METHODS

A total of 18 articles representing 12 independent study populations met our inclusion criteria.

RESULTS

A statistically significant 44% (summary relative risk estimate [SRRE] = 0.56, 95% confidence interval 0.40-0.77) reduced risk of atopic manifestations, which included AD, was found among infants receiving PHF-W compared with infants receiving CMF. In a subanalysis of 4 studies that reported results specifically for AD and that were considered of superior methodological quality, the incidence of AD was reduced by 55% (SRRE = 0.45, 95% confidence interval 0.30-0.70).

CONCLUSIONS

Regardless of study design, infant population, follow-up time, or study location, individual study findings were consistent because a reduced incidence of AD was reported in all of the reviewed studies. Exclusive breast-feeding should be encouraged as the standard for infant nutrition in the first months of life. For infants who are not exclusively breast-fed, feeding with PHF-W instead of CMF reduces the risk of AD in infants, particularly in infants with a family history of allergy.

Meta-analysis of the evidence for a partially hydrolyzed 100% whey formula for the prevention of allergic diseases

OBJECTIVE

Infants with a documented hereditary risk of atopy (i.e., an affected parent and/or sibling) who cannot be breastfed exclusively are recommended to receive a formula with confirmed reduced allergenicity, i.e., a partially or extensively hydrolyzed formula (pHF and eHF, respectively), as a means of preventing allergic reactions. The efficacy of each hydrolyzed formula for the prevention of allergic diseases should be established separately, as factors such as the protein source, hydrolysis method and degree of hydrolysis that often depend on the manufacturer contribute to differences among hydrolysates. The aim was to systematically review data on the efficacy of a partially hydrolyzed 100% whey formula (pHF) in reducing the risk of allergy in healthy infants at high risk for allergy.

METHODS

The Cochrane Library, MEDLINE, EMBASE, and CINAHL databases were searched in September 2009 (from inception to September 2009) for randomized and quasi-randomized controlled trials (RCTs); additional references were obtained from reviewed articles. The company that manufactures the pHF used was contacted for unpublished data.

RESULTS

The search yielded 84 citations. Fifteen RCTs were included, some of which had potential methodological limitations such as unclear or inadequate allocation concealment, no intention-to-treat analysis, and no true blinding. For primary outcomes, i.e., all allergic diseases and atopic eczema/atopic dermatitis, use of the pHF compared with standard formula (SF) was associated with reduced risks (incidence, cumulative incidence, period prevalence) that were statistically significant for most, albeit not all, time points. Comparison of groups who received the pHF versus extensively hydrolyzed (eH) whey formula revealed no significant differences in outcomes except for reductions in the cumulative incidences of all allergic diseases at 0 to 36 months of age. Comparison of groups who received the pHF versus eH casein formula revealed no significant difference in outcomes between groups.

CONCLUSIONS

The use of the pHF compared to SF is effective in allergy prevention in children at high risk for allergy at most time points. These results should be interpreted with caution due to a lack of methodological rigor in many trials. Reassuringly, the strongest evidence comes from a well-designed and conducted, independently funded RCT.

Clinical practice: Breastfeeding and the prevention of allergy

The increase in allergic disease prevalence has led to heightened interest in the factors determining allergy risk, fueled by the hope that by influencing these factors one could reduce the prevalence of allergic conditions. The most important modifiable risk factors for allergy are maternal smoking behaviour and the type of feeding. A smoke-free environment for the child (to be), exclusive breastfeeding for 4-6 months and the postponement of supplementary feeding (solids) until 4 months of age are the main measures considered effective. There is no place for restricted diets during pregnancy or lactation. Although meta-analyses suggest that hypoallergenic formula after weaning from breastfeeding grants protection against the development of allergic disease, the evidence is limited and weak. Moreover, all current feeding measures aiming at allergy prevention fail to show effects on allergic manifestations later in life, such as asthma. In conclusion, the allergy preventive effect of dietary interventions in infancy is limited. Counselling of future parents on allergy prevention should pay attention to these limitations.

Effects of food processing on food allergens

Food allergies are on the rise in Western countries. With the food allergen labeling requirements in the US and EU, there is an interest in learning how food processing affects food allergens. Numerous foods are processed in different ways at home, in institutional settings, and in industry. Depending on the processing method and the food, partial or complete removal of the offending allergen may be possible as illustrated by reduction of peanut allergen in vitro IgE immunoreactivity upon soaking and blanching treatments. When the allergen is discretely located in a food, one may physically separate and remove it from the food. For example, lye peeling has been reported to produce hypoallergenic peach nectar. Protein denaturation and/or hydrolysis during food processing can be used to produce hypoallergenic products. This paper provides a short overview of basic principles of food processing followed by examples of their effects on food allergen stability. Reviewed literature suggests assessment of processing effects on clinically relevant reactivity of food allergens is warranted.

Infant feeding and allergy prevention: a review of current knowledge and recommendations. A EuroPrevall state of the art paper

The relationship between infant feeding patterns and the later development of food allergies has been the focus of much debate and research over the last decade. National recommendations have been made by many countries on how to feed infants to reduce the risk of food allergy but due to the lack of firm evidence the recommendations differ widely. This review has been developed as part of EuroPrevall, a European multicentre research project funded by the European Union, to document the differing feeding recommendations made across Europe, to investigate the current evidence base for any allergy prevention feeding recommendations and to identify areas where further research is needed. This review will also provide information which, when combined with the infant feeding data collected as part of EuroPrevall, will give an indication of compliance to national feeding guidelines which can be utilised to assess the effectiveness of current dissemination and implementation strategies.

A new sample preparation method compatible with capillary electrophoresis and laser-induced fluorescence for improving detection of low levels of beta-lactoglobulin in infant foods

Beta-lactoglobulin (betaLG) is the main allergenic protein in cow's milk and can cause allergy even when present at very low concentration. The aim of this work is to develop an innovative sample preparation method fully compatible with capillary electrophoresis and laser-induced fluorescence detection for improving the sensitivity when analyzing betaLG. Different types of baby food were on purpose contaminated with diverse dairy desserts and submitted to thermal treatment to simulate potential contamination at production. Sample preparation prior to CE analysis was performed by the classical extraction method and by the innovative one, and the results were compared. Analysis was performed by capillary electrophoresis with laser-induced fluorescence detection. The innovative method permitted to detect contaminations as low as 1 part of yoghurt in 10,000 parts of baby food.

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.

High levels of IgG4 antibodies to foods during infancy are associated with tolerance to corresponding foods later in life

Children with eczema and sensitization to foods are recommended skin care and, if food allergy is proven by challenge, an elimination diet. For most children the diet period is transient, but the process behind tolerance development and the influence of decreased allergen exposure is not fully known. The aim of the study was to investigate the effect of elimination diet on serum and salivary antibodies and to identify immunological parameters related to the ability to tolerate foods. Eighty-nine children, below 2 yr of age, with eczema and suspected food allergy were included. Recommended treatment was skin care to all children, and 60 children had a period of elimination diet. At 4(1/2) yr of age, the children were divided into two groups, based on if they had been able to introduce the eliminated foods, or not. Serum and salivary antibodies were analyzed with enzyme-linked immunosorbent assay and UniCAP before and after a 6-wk treatment period and at 4(1/2) yr of age. Children sensitized to egg and/or milk that could eat and drink the offending foods at 4(1/2) yr of age, had higher levels of Immunoglobulin G(4) antibodies to ovalbumin and beta-lactoglobulin and also higher IgG(4)/Immunoglobulin E ratios on inclusion in the study, than those who had to eliminate egg and/or milk from their diet, beyond 4(1/2) yr of age. The highest IgG(4)/IgE ratios were found in children with circulating IgE antibodies to egg and/or milk but negative skin prick test on inclusion. The 6-wk treatment period did not significantly affect the levels of serum and salivary antibodies. In conclusion, eczematous, food sensitized infants with high levels of IgG(4) and high ratios of IgG(4)/IgE antibodies to food allergens are more likely to consume these foods at 4(1/2) yr than infants with low levels and ratios.

Management of atopic dermatitis in the pediatric population

Atopic dermatitis, one of the most common skin disorders in young children, has a prevalence of 10% to 20% in the first decade of life. It is a chronic illness that requires a multifaceted treatment strategy in the setting of limited therapeutic options. Balancing safety concerns with efficacious treatment is of particular importance in the pediatric population. Parents of patients with atopic dermatitis turn to their primary caregivers for guidance regarding this physically demanding and psychologically stressful condition. In addition to serving as a review of atopic dermatitis, this article delves into the state-of-the-art therapeutic options and includes a detailed review of the differences between topical corticosteroids and topical calcineurin inhibitors. We also discuss new treatment strategies that are being used by atopic dermatitis specialists, such as comprehensive "education-as-intervention" models, wet wraps, bleach baths, and systemic immunomodulatory therapies.

Preventive effect of hydrolyzed infant formulas persists until age 6 years: long-term results from the German Infant Nutritional Intervention Study (GINI)

BACKGROUND

The long-term effect of nutritional intervention with hydrolyzed infant formulas on allergy development has not been sufficiently evaluated.

OBJECTIVE

We performed a follow-up of the German Infant Nutritional Intervention study until 6 years of life to investigate the long-term allergy-preventive effect of 3 hydrolyzed infant formulas compared with cow's milk formula (CMF) in a randomized, double-blind trial.

METHODS

Between 1995 and 1998, 2252 newborns with atopic heredity were randomly assigned at birth to receive one of 4 blinded formulas: partially or extensively hydrolyzed whey formula, extensively hydrolyzed casein formula, or CMF as milk substitute for the first 4 months when breast-feeding was insufficient. The cohort was followed from birth until 6 years of age with yearly questionnaires. Outcomes were physician-diagnosed allergic diseases (atopic dermatitis, food allergy, allergic urticaria, asthma, and hay fever/allergic rhinitis). Log-binomial regression modeled with generalized estimation equations was used for the statistical analysis.

RESULTS

In the intent-to-treat analysis the relative risk of a physician's diagnosis of allergic manifestation (AM) compared with CMF was 0.82 (95% CI, 0.70-0.96) for partially hydrolyzed whey formula, 0.90 (95% CI, 0.78-1.04) for extensively hydrolyzed whey formula, and 0.80 (95% CI, 0.69-0.93) for extensively hydrolyzed casein formula. The corresponding figures for atopic eczema were 0.79 (95% CI, 0.64-0.97), 0.92 (95% CI, 0.76-1.11), and 0.71 (95% CI, 0.58-0.88), respectively. In the per-protocol analysis all effects were stronger and significant. No significant effect on other AMs was found.

CONCLUSION

The data confirm a long-term allergy-preventive effect of hydrolyzed infant formulas on AM and atopic eczema until 6 years of age.

Dietary approaches to the prevention of food allergy

PURPOSE OF REVIEW

The primary prevention of food allergy and atopy has become a public health priority in developed countries. Although some preventive dietary interventions have entered common practice, the level of evidence underpinning these strategies varies.

RECENT FINDINGS

Exclusive breast-feeding and delayed introduction of complementary foods from the age of 4-6 months are key strategies in primary food allergy and atopy prevention. Maternal elimination diets during pregnancy and lactation are currently not recommended. Partially and extensively hydrolyzed formulae may confer a small preventive effect in high-risk infants. Amino acid-based formula is, however, considered a treatment formula and not recommended for primary allergy prevention. The effect of prebiotic oligosaccharides and probiotic bacteria in prevention of food allergy remains unclear and requires further investigation. Maternal fish oil supplementation during pregnancy shows promise in reducing the risk of allergic sensitization in the infant, but prospective long-term data are required. Fish oil supplementation in young infants was not effective.

SUMMARY

Although there is evidence for the primary dietary prevention of eczema and possible respiratory allergies, data on food allergy prevention have, so far, remained less convincing. Further prospective research is needed to clarify the effectiveness of dietary interventions in primary food allergy prevention.