Interaction of early infant feeding, heredity and other environmental factors as determinants in the development of allergy and sensitization

Abstract

The role of early infant nutrition in the development of allergic symptoms and allergic sensitization has been disputed for 70 years. Interaction between genetic factors and infant feeding has been limited to studies on parental heredity of allergy and length of breastfeeding, as well as the qualities of breast milk. In the 10 original studies comparing the development of allergic symptoms among children in whom breastfeeding duration was used as a risk factor separately among those with either positive or negative parental heredity for atopy, no definite answer could be found. The effect of early feeding was even changed in both heredity negative and positive groups when looking at symptoms at ages 2 and 5 years. Of 9 possible combinations, 6 were present in the studies, and none in more than 2 studies. For sensitization, long breastfeeding was a risk in 3 of 5 reports if the family history of allergy was positive, and in 2 if negative. Low levels of soluble CD14 and cow's milk-specific IgA antibodies in breast milk may increase an infant's risk of developing allergy.