A systematic review of the role of hydrolyzed infant formulas in allergy prevention.

OBJECTIVE To critically examine the published literature to determine whether feeding hydrolyzed infant formulas from birth has a role in allergy prevention. DATA SOURCES We identified data through a MEDLINE search using allergy prevention and infant formulas as indexing terms. The search was restricted to 1985 through the present, English-language articles, and human subjects. STUDY SELECTION Criteria for inclusion in the review were prospective controlled trials published in peer-reviewed journals. DATA EXTRACTION Symptoms of allergy were defined and observed by health care providers (physicians and nurses). DATA SYNTHESIS Nine published trials evaluated the use of extensively hydrolyzed formulas, 12 evaluated the use of partially hydrolyzed formulas in high-risk infants, and 1 evaluated the use of partially hydrolyzed formulas in an unselected infant population. The reports compared hydrolyzed formulas with breastfeeding, cow's milk formulas, soy formulas, and combinations thereof. The cohort of studies consistently showed reductions in the cumulative incidence of atopic disease from 12 to 60 months of age among high-risk infants fed extensively hydrolyzed casein formulas or partially hydrolyzed whey formulas vs cow's milk formulas. No studies showed an increase in allergy risk with any hydrolyzed formulas. CONCLUSIONS Extensively hydrolyzed casein formulas and partially hydrolyzed whey formulas are appropriate alternatives to breast milk for allergy prevention in infants at risk. Because atopic disease in children cannot be predicted, the use of these formulas in the general population should be considered, and one must weigh cost, compliance, and long-term benefits.