Deep Dive: Does early exposure reduce food allergies in infants?

Food allergies are present in roughly 8%^[1] of all children in the U.S. As shown in Figure 1, among those with food allergies, about 40%^[1] have a severe food allergy to common foods like peanuts, milk, or shellfish. Over the last several decades, there has been an increasing interest in reducing the development of food allergies through exposure therapy during the first year of life^[2]. Many randomized trials have been performed to examine the efficacy of early exposure of potential allergens in reducing the development of food allergies. Recently, a meta-analysis^[3] found that exposing infants between four and six months of age to eggs and peanuts reduces the risk of developing an allergy to these foods, with one study^[4] showing substantial reductions in allergy development (from about a 14% prevalence to 2% prevalence).

Previous studies, such as the LEAP^[4] trial, have primarily focused on single allergens (i.e.peanuts) and were conducted in high-risk infants. The present study was a secondary analysis of a population-based randomized controlled trial called the EAT^[5] trial that was conducted among average-risk infants who had been exclusively breastfed up to six months of age and were then exposed to a range of possibly allergenic foods depicted in Figure 2. In the original EAT^[5] trial, the intention-to-treat analysis failed to reach significance, likely due to low adherence. The low adherence, coupled with the fact that the infants were not high risk, led the investigators to ask more for focused questions in this study, which is a secondary analysis of the EAT trial. The primary aim of the study under review was to test the hypothesis that early exposure to potential food allergens would reduce the risk of childhood food allergies in a higher risk subset of the original trial.

Food allergies, which can be fatal, affect roughly 8% of all children. Exposing infants to allergy causing foods early in life has been shown to reduce the risk of developing food allergies. The present study was a secondary analysis of a high-risk population of infants from a randomized controlled trial examining the effect of early exposure to several different potentially allergy-causing proteins on the development of food allergies later in life.