Early cow's milk exposure may have protective effect

While it is believed the majority of children with cow's milk allergy outgrow their condition, there are a range of estimates of how many individuals this relates to. Researchers from Tel Aviv University in Israel conducted a study of 13,000 infants born in an Israeli hospital between 2004 and 2006 to collect clear and accurate data on this subject, and uncovered some interesting results in relation to age of first exposure.

The initial aim of the study was to establish the actual prevalence of IgE-mediated cow's milk allergy. To do this, the researchers gathered information by telephone survey or questionnaire about each child's early feeding history (breast milk, cow's milk, and soy milk) and any allergic reactions. Those reported to have had a reaction to cow's milk were subjected to an allergy skin test and an oral challenge to milk.

Only 0.05% of infants who were introduced to cow's milk within the first 14 days of life developed classic cow's milk allergy, compared with 1.75% of the babies who began cow's milk at a later age. The authors believe these results support the introduction cow's milk at an earlier age as a supplement to breastfeeding as a means to prevent the development of IgE-mediated cow's milk allergy.

A secondary aim of the study was to examine cow's milk and soy cross-reactivity. The researchers found no link between cow's milk and soy allergies.

Reference: Katz et al. 2010. Journal of Allergy and Clinical Immunology. Vol 126(1) pp. 77-82.e1