Is it Worth it to Start Allergic Foods Early?
Perkin MR, Logan K, Tseng A, et al; EAT Study Team. Randomized trial of introduction of allergenic foods in breast-fed infants. N Engl J Med. 2016;374(18):1733-1743.
Food allergy is increasingly common among children and can occur in up to 8% of children younger than 3 years of age. As a result, the time frame during which to introduce allergenic foods to infants has become uncertain and marked by a great deal of parental anxiety. Parents and caretakers were told for decades to avoid highly allergenic foods at a young age, with the idea that early exposure led to allergic sensitization. However, the Learning Early About Peanut Allergy (LEAP) trial recently revealed that early exposure to peanut in a high-risk population significantly decreased the risk of developing a peanut allergy.
With this concept in mind, the Enquiring About Tolerance (EAT) trial extended the investigation to the general population and to the introduction of other allergenic foods in addition to peanut. Perkin and colleagues conducted a randomized, controlled trial to examine whether introducing several common food allergens (peanut, cooked hen’s egg, cow’s milk, sesame, whitefish, and wheat) at 3 months of age in exclusively breast-fed infants in the general population would prevent food allergies in the first 3 years of life compared with infants who were exclusively breast-fed for approximately 6 months.
More than 1300 infants were randomly assigned to the introduction of 6 allergenic foods (early-introduction group) or the standard United Kingdom recommendation of exclusively breast-feeding until 6 months of age (standard-introduction group). The parents of the infants in the early-introduction group were told to give the children specific amounts of each of the foods every week. All the children were followed until age 3 years. The early-introduction group underwent skin-prick testing at baseline.
The primary outcome was challenge-proven food allergy to any of the early introduction foods between ages 1 and 3 years, which was examined with an intention-to-treat analysis using a X2test. Secondary outcomes were allergy to individual foods and positive results on skin-prick testing for individual foods. These outcomes were examined using X2 tests or Fisher’s exact test. Of note, the per-protocol population included the participants who adhered appropriately to the assigned regimen of allergic foods.
In the intention-to-treat analysis, there was not a significant difference in the diagnosis of food allergy between the early-introduction group and the standard-introduction group. Food allergy diagnosis at the start of the study was significantly associated with nonwhite race, having siblings, and the presence of eczema at the start of the study. In the per-protocol analysis, the prevalence of any food allergy was significantly lower in the early-introduction group than in the standard-introduction group. This was consistent with what was found in the skin-prick testing group as well. The researchers also noted that consuming 2 g per week of peanut or egg-white protein was associated with a significantly lower prevalence of these allergies when compared with consuming smaller amounts, suggesting a dose-related effect.
The study’s results indicated that early introduction to all these foods seemed safe, but the protocol prescribed to initiate the foods was difficult for many caretakers to achieve (less than half of the participants in the early-introduction group adhered to the protocol). This lack of adherence makes the interpretation of the significant per-protocol results more challenging. Aversive feeding behavior can be the first sign of clinical food allergy, and this behavior could have created difficult situations to continue administering the allergenic foods as prescribed. Providers also struggled with some of textural aspects of these foods in the setting of immature motor skills and concerns for choking.
Though this study failed to show a lower rate in food allergy in children introduced at an earlier age in the intention-to-treat analysis, further investigation certainly seems warranted. In particular, more research should focus on the dose required to prevent allergies and the development of an early-feeding strategy that feels safe and more amenable to daily life. n
Jessica Tomaszewski, MD, is an Assistant Clinical Professor of Pediatrics at the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, Pennsylvania, and a hospitalist pediatrician at Nemours/Alfred I. duPont Hospital for Children in Wilmington, Delaware.
Charles A. Pohl, MD—Series Editor, is a Professor of Pediatrics, Senior Associate Dean of Student Affairs and Career Counseling, and Associate Provost for Student Affairs at the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, Pennsylvania.