Cow's milk allergy in breast-fed infants

Nutrition Research Newsletter, Jan, 1989

COW'S MILK ALLERGY IN BREAST-FED INFANTS

It is well recognized that breast-fed infants may react to foods consumed by the mother, because allergenic components may be passed to the infant in breast milk. The incidence, characteristics, and possible predisposing factors for cow's milk allergy in breast-fed infants were investigated in a recent study conducted in an urban Danish community. A cohort of 1,749 newborns in Odense was followed prospectively for the first year of life. Cow's milk allergy was identified in 39 of these infants (2.2%), using standard diagnostic criteria. Of these 39, nine were being exclusively breast-fed at the time of diagnosis, which was before the age of three months in all cases. All nine became symptom-free when their mothers consumed a diet free from cow's milk, and identical symptoms reappeared when cow's milk was reintroduced into the mothers' diets. Symptoms in these nine infants included eczema (8), gastrointestinal symptoms (6), and respiratory symptoms (3). Six of the infants remained intolerant to cow's milk at the age of 12 months. Bovine beta-lactoglobulin was detected in milk samples from three of the nine mothers when the mothers were consuming a normal diet including cow's milk. Hospital nursery records showed that all nine affected infants had received supplements of infant formula during the first three days of life. None showed allergy symptoms at that time. All 39 of the infants who developed cow's milk allergy were among the 1,539 who received formula in the hospital; none of the 210 infants who did not receive formula developed cow's milk allergy. The difference is statistically significant. The authors suggest that early exposure to cow's milk proteins may sensitize infants who are predisposed to allergy. Because of this risk, "it seems reasonable to warn against occasional and unnecessary supplements of cow's milk formula to newborns, in whom sufficient breast-feeding is established."