Is prevention of food allergy worthwhile?

Several studies performed in high-risk babies have demonstrated a significant reduction in the prevalence and severity of atopic diseases with dietary and environmental manipulations. It has been demonstrated that prolonged breast-feeding and the avoidance of cow's milk, eggs and fish during the first three months of lactation significantly decrease both the prevalence and the severity of atopic disease up to the age of 5 years. We have shown a significant reduction in both the prevalence and the incidence of atopic dermatitis, food allergy and asthma in high-risk children followed up to the age of 5 years who received preventive dietary (prolonged breast-feeding, cow's milk- and egg-free diet to the nursing mothers, supplementation with a soya formula containing sucrose when breast milk was not available, delayed weaning) and environmental measures (no smoking and no pets in the house, measures for the elimination of mites, etc.). However, occasionally, breast-fed infants may experience allergic sensitization to food antigens ingested by the mother during lactation. The factors that determine which infants will develop sensitization to food antigens in breast milk are not fully understood. The genetic predisposition to IgE-mediated hypersensitivity reactions is certainly a prerequisite; however, properties of human milk, such as immune characteristics, may play a role in the phenotypic expression of sensitization. Our studies suggest that the abnormally low levels of the long-chain polyunsaturated derivatives found in infants at risk of atopy are unlikely to be corrected by breast-feeding and may explain the contradictory results from studies on the effectiveness of breast milk against the development of atopic dermatitis.