The current consensus is that parents should try to introduce foods such as peanuts before the age of 1 year, and they are encouraged to make it a natural introduction. In the early 2000s, parents were encouraged to delay the introduction of peanuts, tree nuts, and eggs until ages 2 to 3 years. At that time, the rationale was that a delayed introduction may allow for gut and immune system maturation and might help in food allergy prevention.

However, starting in 2008, observational studies began to emerge, suggesting that early food introduction may actually lower the risk of common food allergies, such as milk, egg, or peanut, and the guidance was therefore changed. Although this relatively rapid change was likely a cause of confusion and perhaps some skepticism initially, I believe that, today, we have gotten to the point where the current recommendations are more trusted, in part due to the findings of randomized clinical studies such as the LEAP trial. The LEAP trial randomized 640 infants between 4 and 11 months of age, with severe eczema and/or egg allergy, to consume or avoid peanut-containing foods until 60 months of age, when a peanut oral food challenge was conducted to determine the prevalence of peanut allergy. The prevalence of peanut allergy at 60 months of age was 13.7% in the peanut avoidance group and 1.9% in the peanut consumption group. In 2017, guidelines issued by the National Institute of Allergy and Infectious Diseases recommended peanut introduction between the ages of 4 and 6 months.

Additionally, pediatricians are on the front lines, talking to parents about early nutrition, and I think that we continue to refine the guidelines to be sensitive to that fact. For instance, we do not want to be asking pediatricians to perform tests and/or to schedule observed food introductions when they are not set up to do that. The latest guidance really gives parents a window of opportunity for introducing foods that are associated with allergy, such as peanuts. It does not have to be precisely at 4 to 6 months; one could introduce peanuts from 6 to 11 months of age. A 2021 consensus statement went beyond peanuts to recommend the early introduction of eggs and other top food allergens as a means of reducing the development of allergies to those foods.

Not every case of food allergy will be prevented, but our feeling is that parents should try to have children eat common food allergens before the age of 1 year, as naturally as possible and without worry over some strict frequency or the number of grams eaten. If the child enjoys peanut butter, for example, encourage them to eat it early and often, but do not stress about giving them exactly 2 grams 3 times a week. While parents do not necessarily have to bring their child to an allergist for testing prior to early food introduction, some may want to do so. However, allergy testing should be limited in the setting of an infant not having eaten a food such as peanut. In the event of a positive test but an absence of a clinical reaction to peanuts, that positive test is more likely to be a false positive, so an allergist-supervised oral food challenge would be warranted in such a case to determine whether or not the patient has a true allergy. And, if a child has already reacted to a food, they should consider being seen by an allergist before other major food allergens are introduced.

Any child can benefit from early food introduction, regardless of whether they are considered to be high risk. If parents are concerned about introducing a particular food to their child, pediatricians can refer them to an allergist who does infant oral food challenges. If the child has a reaction, the most common symptoms will be vomiting and hives. Anaphylaxis is a possibility even in infants and toddlers, but life-threatening reactions in infants are uncommon. Promoting early food introduction should decrease the occurrence of food allergies; however, early exposure is only 1 factor that is involved, and other factors play a role in the development of food allergies. New data are likely to show that introducing foods early is just a single aspect of preventing these allergies.