Infant feeding and allergy. Soy versus cow's milk in infants with a biparental history of atopic disease: development of atopic disease and immunoglobulins from birth to 4 years of age.
The effect of withholding cows' milk was examined in 487 infants at high risk of allergic disease. Before birth they were randomly allocated either to a control group, most of whom received cows' milk preparations, or to an intervention group, who were offered a soya based substitute. Eczema and wheezing occurred to a similar extent in the two groups during the first year of life, although napkin rash, diarrhoea, and oral thrush were commoner in the intervention group, especially during the first three months. Breast feeding for any length of time was associated with a reduced incidence of wheezing and diarrhoea. Forty-eight children with a biparental history of atopic disease were followed from birth to 4 years of age. One group was fed soy and the other cow's milk from weaning to 9 months of age. Two-thirds of the children developed symptoms of atopic disease with no significant difference between the groups. No difference was found in the serum immunoglobulins (IgE antibodies, IgA, IgG and IgM) during the observation period. The soy fed children showed transiently lower levels of IgG antibodies to cow's milk but higher levels of IgG antibodies to soy protein. Six children showed cow's milk intolerance and a further five had symptoms possibly related to the use of cow's milk. Withholding cow's milk during the first 9 months did not reduce the incidence of symptoms of cow's milk intolerance from birth to 4 years of age. Thus, no benefit was found from replacing cows' milk with soy. A prolonged breast feeding seems most rational for infants at risk of developing atopic disease, even if the present study did not show evidence of a prophylactic effect of breast milk against the development of atopic disease.
Feeding with a soy formula cannot be recommended for prevention of allergy or food intolerance in infants at high risk of allergy or food intolerance. Further research may be warranted to determine the role of soy formulas for prevention of allergy or food intolerance in infants unable to be breast fed with a strong family history of allergy or cow's milk protein intolerance.