Dietary Interventions for Allergy Prevention

Eczema and the Atopic March

Allergic diseases are common, and their incidence is increasing in many countries. Typically, atopic disorders manifest as food allergies or eczema during early infancy. In about 60% of cases, atopic dermatitis begins within the first year of life. Although symptoms may resolve with increasing age, multiple studies now suggest that eczema may be a possible first step in the progression of the allergic march to allergic rhinitis and asthma.1 Furthermore, it has been proposed that food allergies may be triggered through early cutaneous exposure to food protein, particularly in infants with disrupted skin barriers due to eczema. Any strategy for the primary prevention of allergy must therefore focus on the first years of life, when these critical events occur.

The GINI Study

The German Infant Nutritional Intervention (GINI) study is an ongoing birth cohort study started in 1994 to evaluate the long-term effects of hydrolyzed formulae on allergic diseases in high-risk children. In 2010, data from this study highlighted the role of genetic factors in the development of eczema; children with a family history of atopy had a 2.1 times higher risk for eczema than children without a familial predisposition. Importantly, the study also showed that even without a family history of allergy, as many as 15% to 18% of children still develop eczema. Breastfeeding and Allergy Prevention An effective intervention for the prevention of allergy is exclusive breastfeeding for 4 months. Current evidence suggests that the exclusion of antigens, such as milk or egg, from the maternal diet does not reduce her child's risk of atopic disease. Likewise, maternal peanut and tree nut intake during pregnancy was found to be inversely related to asthma and allergic rhinitis in children at 18 months of age. There is also some evidence suggesting that maternal fish intake and the consumption of a Mediterranean diet may have protective effects against asthma and atopy in children. Hydrolyzed Formulae and Allergy Prevention In the absence of human milk, cow’s milk-based hydrolyzed protein formulae, meeting strictly regulated nutritional and safety requirements, may be useful. Recently published data from the 20-year follow-up of the GINI study showed that in formula-fed infants (exclusively or mixed feeding) at risk of allergies, feeding an extensively hydrolyzed casein (eHF-C) and a partially hydrolyzed whey (pHF-W) formula during the first 4 months of life reduced the risk of eczema and asthma up to young adulthood. In the intention-to-treat (ITT) analysis, asthma prevalence between 16 and 20 years was significantly lower in the eHF-C group and in the pHF-W group compared to standard cow’s milk formula (CMF) [Table 1]. The risk-reducing effects of eHF-C and pHF-W on eczema was also strongly demonstrated in the per-protocol (PP) analysis [Table 2], consistent with the results reported during the 15-year follow-up of the GINI study.²

Table 1. Period prevalence of asthma between 16 and 20 years and adjusted odds ratios (aOR) for the three different hydrolyzed formula groups, when compared to the cow's milk formula group (Intention-to-treat analysis).

CMF, standard cow's milk formula; pHF-W, partially hydrolyzed whey; eHF-W, extensively hydrolyzed whey; eHF-C extensively hydrolyzed casein formula

*Adjusted for parental history of disease, heredity of family allergy, sex, study region, education and cigarette smoking of young adult, actual pets and type of questionnaire.

Table 2. Cumulative incidence (from birth to 20 years) of eczema and adjusted risk ratios (aRR) for the three different hydrolyzed formula groups, when compared to the cow's milk formula group (Per protocol analysis).

CMF, standard cow's milk formula; pHF-W, partially hydrolyzed whey; eHF-W, extensively hydrolyzed whey; eHF-C extensively hydrolyzed casein formula

*Adjusted for parental history of disease, heredity of family allergy, sex, study region.

The GINI study demonstrates that only certain formulae confer protective effects against allergic diseases during childhood up to adult life. It is important to note that the effects of hydrolyzed formulae for prevention of allergic disease are affected by several factors, such as protein source, method of hydrolysis, and degree of hydrolysis resulting in different peptides and their possible effects on microbiome and immune response. The efficacy should be evaluated for each hydrolyzed protein formula.

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