Breast milk--immunomodulatory signals against allergic diseases.

Breastfeeding holds a key position with regard to the increasing burden of allergic diseases in the industrialized countries. Not only does it provide the infant with nutrients for growth and development, it also confers immunological protection during a critical period in life, when the infant's own defense mechanisms are immature. A delicate balance of stimulatory, even inflammatory, maturational signals, together with a myriad of anti-inflammatory compounds, is transferred from mother to infant via breastfeeding. Breastfeeding mothers, however, do not constitute a uniform group. The composition of breast milk shows marked individual variation and so, consequently, does the success of breastfeeding in reducing the risk of disease. Recent clinical studies indicate that the potential of breastfeeding to counteract allergic disease may be promoted by dietary means. While uncoordinated elimination diets result in a risk of general nutritional inadequacy or deficiency of essential single nutrients, a balanced diet following current dietary recommendations, specifically containing fresh fruits and vegetables (antioxidants) and fat of predominantly vegetable origin, may be associated with a lower incidence of atopy in the infant. As early nutrition appears to program the subsequent health of the child, the importance of the maternal dietary composition during breastfeeding should be emphasized. In future, an improved understanding of the mechanisms of this programming may offer specific therapeutic modalities for the prevention of allergic disease.