Background: In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease when breast-feeding is not possible or supplemental feeding is needed. Most infant formulas are based on cow's milk protein. Alternative choices include soya based and hydrolysed cows milk formulas.
Objectives: To estimate the effect of dietary avoidance of cow's milk protein on the development of asthma or wheeze in children.
Search strategy: The Cochrane database was searched for eligible trials until February 2002. The full text papers of all abstracts identified as RCTs were obtained and reviewed independently by two reviewers.
Selection criteria: Randomised controlled trials involving children with a family history of atopy in at least one first degree relative were considered if feeding with cow's milk based standard formula was compared to dietary avoidance of cow's milk protein using soya or other hypoallergenic formula during the initial four months of life or longer.
Data collection and analysis: Two reviewers extracted data independently. A priori defined subgroups were the types of hypoallergenic artificial feed and dietary restrictions on mother and/or child's diet.
Main results: Six trials used hydrolysed formula for at least 4 months in addition to dietary restrictions and in some cases dust-mite reduction measures. The risk of infants experiencing asthma or wheeze during the first year of life was reduced compared to standard cow's milk based formula (Relative Risk =0.40, 95% Confidence Intervals 0.19, 0.85). Feeding soya-based formula as opposed to standard cow's milk formula did not reduce the risk of having asthma or wheeze at any age.
Reviewer's conclusions: Breast-milk should remain the feed of choice for all babies. In infants with at least one first degree relative with atopy, hydrolysed formula for a minimum of 4 months combined with dietary restrictions and environment measures may reduce the risk of developing asthma or wheeze in the first year of life. There is insufficient evidence to suggest that soya-based milk formula has any benefit.