PREVENTION OF FOOD ALLERGY IN INFANTS AND CHILDREN*

Adherence to recommendations for primary prevention of atopic disease in neonatology clinical practice

The prevalence and severity of atopic manifestations in children are increasing in western countries in the last decades. Specific nutritional intervention may prevent or delay the onset of atopic diseases in infants at high risk of developing allergy. These nutritional interventions should be applied early in the perinatal period to have a chance of success. Thus, we assessed adherence to the dietary management recommendations of the Committee on Nutrition and Section on Allergy and Immunology of the American Academy of Pediatrics (AAP) for the prevention of atopic diseases in neonatal age through an audit study. Questionnaire was administered to the chiefs of 30 maternity units (MU) with more than 1500 live births/yr to report the policy applied in their MU. Twenty-two MU returned the questionnaire. Identification of high-risk newborns was routinely performed only in 7/22 MU (31.8%). High-risk newborns were identified by the presence of at least two or one first-degree relative (parent or sibling) with documented allergic disease by 18.2% and 45.5% of MU, respectively. Specific maternal dietary restrictions during lactation were adopted in 7/22 MU (31.8%). Extensively or partially hydrolyzed formula was prescribed for bottle-fed high-risk infants in 22.7% of MU. Only 2/22 MU have a policy in complete agreement with the nutritional intervention proposed by the AAP. Our study suggest a poor adherence to dietary recommendations for primary prevention of atopic disease in neonatology clinical practice. Further efforts should be planned to improve the knowledge and the application of these preventive strategies.

Preventing food allergy

In this review, we examine the critical periods of immune development and how these might be modified to prevent food allergy. The relevant dietary intervention studies, roles of microorganisms and their products, and other strategies are critically analyzed. Additionally, we highlight the potential importance of different routes of allergic sensitization and the role of oral tolerance induction in the pathogenesis and prevention of food allergy.

Cow's milk-specific cellular and humoral immune responses and atopy skin symptoms in infants from atopic families fed a partially (pHF) or extensively (eHF) hydrolyzed infant formula

BACKGROUND

Hydrolyzed milk formulas are recommended to feed infants at high risk of atopy if breast-feeding is not possible. We studied the specific cellular and humoral immune response to cow's milk proteins and occurrence of atopic dermatitis under different feeding regimens: two hydrolyzed infant milk formulas (partially [pHF] and extensively hydrolyzed [eHF]) and under exclusive breast-feeding (BF).

METHODS

Seventy-two infants from families with atopic symptoms were randomized in the pHF and eHF groups, respectively. At 6 and 12 months of age, peripheral blood mononuclear cell proliferation along with specific IgG and IgE to cow's milk proteins was determined in infants fed pHF or eHF, respectively, and those who had not yet received any formula at 6 months of age (BF). Cases of atopic dermatitis were recorded throughout the first 12 months of life, and their severity was evaluated with SCORAD points.

RESULTS

A significantly decreased proliferation to cow's milk caseins was found in the pHF group compared to the exclusively breast-fed group. Medians of stimulation indexes for CAS at 6 months were as follows: pHF 1.18; n=24; BF 1.70; n=24 (P=0.033, Mann-Whitney U-test). Higher levels of plasma IgG antibodies to BCAS were found in infants fed pHF than in those fed eHF at 12 months. Optical density (OD): (25th percentile; median; 75th percentile): pHF: 0.00; 0.14; 0.38; n=30; eHF: 0.00; 0.03; 0.14; n=28; P=0,089, Mann-Whitney U-test. Cow's milk-specific IgE was detected at 6 months as follows: BF: 3 of 24; eHF: 2 of 21; pHF: 0 of 23. The number of cases of atopic dermatitis and their severity did not differ among the groups during the first 12 months.

CONCLUSIONS

Feeding pHF appears to suppress cow's milk-specific cellular responses and stimulate specific IgG production. Specific IgE sensitization can occur also with breast-feeding.

Dietary aspects of food allergy prevention in infants and children

Food allergy occurs in approximately 4% to 6% of children, has increased in prevalence during the past decade, and thus represents a major burden to our young. The natural history of food allergy documents that allergies to cow's milk, egg, and soy frequently remit whereas allergies to peanut, nuts, and fish typically persist to adulthood, although exceptions exist. Food allergen avoidance subsequent to sensitization and manifestation of symptoms appears to hasten tolerance; however, the immunologic mechanism responsible for tolerance to one food group and not another is poorly understood. Identification and characterization of allergens and determination of B- and T-cell epitopes has provided an opportunity to better define these mechanisms. Identifying and developing effective strategies to prevent food and other allergic diseases represents a high priority for medicine at this time because of the unbridled increase in the prevalence and morbidity attributed to them. Immunologic engineering holds the greatest promise for allergy prevention in the not too distant future, but environmental strategies that promote food avoidance provide an avenue for prevention at present. Such efforts rely actively on reducing the food allergenic load and exposure of atopy-prone infants and children.