For years, parents were often advised to wait before giving babies eggs and other foods commonly associated with allergies. Newer guidance has moved in the opposite direction, encouraging families to introduce common allergens during infancy in developmentally appropriate forms.
A large Australian study offers evidence that the shift may be making a difference. Egg allergy prevalence declined after national guidelines began recommending that parents introduce egg during a baby’s first year of life. The findings do not prove that the guideline change alone caused the decline, but they add population-level support to advice already shaped by randomized trials.
The study, published in JAMA Pediatrics, compared two population-based samples of infants in Melbourne, Australia. Researchers studied 5,276 infants recruited from 2007 to 2011 and 1,933 infants recruited from 2018 to 2019. All were between 11 and 15 months old.
The later group was recruited after Australian guidelines changed in 2016 to recommend introducing common allergenic foods during infancy rather than delaying them.
Researchers found that the median age at which babies were first given egg declined from 8 months in the earlier group to 6 months in the later group.
After adjusting for changes in known allergy risk factors, egg allergy prevalence fell from 9.2% to 7.6%. That represents an absolute decline of 1.6 percentage points and a relative reduction of approximately 17%.
The reduction was even greater among babies with early eczema, a known risk factor for food allergies. In that group, egg allergy prevalence declined from 34.6% to 21.9%.
“To our knowledge, this is the first study to show a reduction in egg allergy after the introduction of new infant feeding guidelines at a population level,” said Jennifer Koplin, an associate professor at the University of Queensland’s Child Health Research Centre.
The researchers used more than questionnaires to identify allergies. Infants received skin-prick tests for egg allergy. Babies with positive results then underwent oral food challenges, in which egg was introduced under controlled conditions to determine whether they had an allergic reaction.
The study cannot prove that introducing eggs earlier prevented individual children from developing allergies. Researchers compared two groups of infants recruited during different time periods. Other changes in families, health care or the broader environment may also have influenced allergy rates.
But the results matter because they reflect what happened after feeding advice changed across a population, not only under the carefully controlled conditions of a clinical trial.
The newer approach is a significant departure from the guidance many families received in previous decades. In the 1990s and early 2000s, parents were often told to delay common allergens, particularly when babies had a family history of allergies. Current evidence suggests that waiting may not offer protection and could potentially increase allergy risk.
Current Australian guidance recommends introducing well-cooked egg and peanut in an age-appropriate form soon after a baby is developmentally ready and has started solid foods. This is typically around 6 months of age and not before 4 months. Other common allergens, including cow’s milk, wheat, tree nuts, sesame, soy, fish and shellfish, should generally be introduced during the first year of life.
Advice for American families is broadly similar. The American Academy of Allergy, Asthma & Immunology says egg and other common allergens can be introduced gradually in appropriate forms during infancy after less allergenic foods have been tolerated.
Parents should not give babies raw or runny eggs. A developmentally appropriate option may include a small amount of well-cooked egg, such as mashed hard-boiled egg, once a baby is ready for solid foods.
Families should also introduce new allergens carefully. Offering one new allergen at a meal can make it easier to identify the cause if a baby has a reaction. Once a baby tolerates an allergen, continuing to offer it regularly may be important.
Parents should speak with a pediatrician or allergist before introducing allergens if a baby has moderate to severe eczema, an existing food allergy or a history of reactions. A child who is already known to be allergic to a food should not be given that food without medical guidance.
Earlier introduction does not guarantee that a baby will avoid food allergies. Some children still develop allergies even when families follow current recommendations.
“Although we are beginning to see a reduction in egg allergy, it still remains common,” Koplin said. “Some babies can still develop food allergy despite following the guidelines, and further research is underway and needed, to find other prevention strategies.”
Funding information was not available for this study.