Peanut allergy is one of the most common food allergies affecting Australian children, with around 3% of babies and toddlers currently living with a peanut allergy (here and here). People living with a peanut allergy are at risk for accidental reactions, which can be serious and occasionally life-threatening. The risk of accidental exposure and the vigilance required to maintain avoidance has a significant impact on the quality of life of children living with peanut allergy and their families (here and here).
Peanut allergy is often lifelong. Less than 30% of infants with peanut allergy will outgrow their allergy by school age. Peanut allergy often presents in childhood, with reactions usually occurring when peanuts are first introduced into a child’s diet, although onset peanut allergy has also been reported rear.
Why does the timing of introducing peanuts into the child’s diet matter?
There is convincing evidence from a high-quality randomized controlled trial (the LEAP trial) that introducing peanuts into an infant’s diet during the first year of life reduces the risk of developing peanut allergy. However, this trial was conducted in a select group of infants at high risk of developing peanut allergy, that is, infants with moderately severe early-onset eczema and/or peanut allergy. pre-existing egg, who were previously screened for peanut allergy. inclusion in the study.
The strict entry criteria in this trial may limit its generalizability to other settings, and it is unclear whether early introduction can prevent peanut allergy in the general population, including those at low risk of developing peanut allergy. peanut In our previous population-based food allergy study, nearly a quarter of peanut allergy developed in infants who did not fall within the definition of “high risk for peanut allergy’ used in the previous LEAP trial.
What are the current Australian guidelines on the timing of peanut introduction?
In Australia, infant feeding guidelines for allergy prevention were updated in 2016 in response to emerging research in this area. In 2015, our Center for Food and Allergy Research held an Australian Summit on Infant Feeding to assess new evidence and developed revised recommendations for infant feeding. Three recommendations emerged from national consensus among experts, stakeholders, and researchers. These were:
- introduce solid foods around 6 months of age, but not before 4 months;
- introduce allergenic foods such as peanut butter and boiled egg during the first year of life;
- Hydrolyzed infant formula is not recommended for the prevention of allergic diseases.
The consensus aimed to provide consistency between the different Australian guidelines to ensure clear consumer advice while balancing the need for food allergy prevention with other nutritional priorities, including the known benefits of breastfeeding. These recommendations were subsequently incorporated into the infant feeding guidelines of the Australasian Society of Clinical Immunology and Allergy.
How have infant feeding guidelines changed over the past few decades and what has been the impact of these guidelines?
Allergy prevention guidelines have undergone three major changes since the 1990s. Initially, the guidelines recommended avoiding dietary allergens during childhood because it was thought that this could prevent food allergy. This advice was removed around 2008 as evidence emerged that allergen consumption was important in inducing tolerance, although allergen ingestion was not yet actively encouraged. Only from 2016 was the strong recommendation to introduce allergens during the first year of life to prevent allergy incorporated into Australian and international guidelines.
Given this major shift in focus, it should not have been surprising that parents and health care providers were reluctant to follow the latest advice. Early surveys in the United States noted a lack of willingness to implement early allergen introduction among both parents and health care providers, adding to these concerns.
We also showed in a large population-based Australian cohort that the removal of advice to delay introduction of allergens in 2008 was followed by only a small shift towards earlier introduction of peanut, and most parents continued to avoid giving infants peanut products during the first year of life.
Despite these early concerns, we demonstrated high uptake of early peanut introduction among Australian infants following the 2016 guideline changes. We conducted two large population-based studies in Melbourne, Australia, 10 years apart , with a total of more than 7,000 participants, using the same sampling frame and methods to assess changes in practices around the introduction of eggs and peanuts to infants, as well as food allergy outcomes. .
We demonstrated a striking shift towards earlier peanut introduction, with a threefold increase in the proportion of infants consuming peanuts before one year in 2018-2019 compared to 2007-2011, from 28% to 88 %. Infants at high risk of peanut allergy, that is, those with early-onset eczema, had similarly high rates of early introduction of peanut, ensuring that these guidelines are being adopted by the group that is likely that benefit more from the early introduction of peanut. These findings were supported by a national survey of 1940 parents, which showed similarly high rates of peanut introduction to infants at 12 months (86%).
Although the community responded well to the new infant feeding guidelines, the bigger question was whether this had the desired effect of reducing the prevalence of peanut allergy. We compared the impact of earlier introduction of peanut on the prevalence of peanut allergy using data from these same two population-based studies. Despite the large increase in early introduction of peanut, we found only a relatively small reduction in the prevalence of peanut allergy, from 3.1% to 2.6%, highlighting that more needs to be done to prevent peanut allergy in the general population.
However, it should be noted that, as expected, earlier peanut introduction was still associated with a reduced risk of peanut allergy and that the reduced prevalence of peanut allergy seemed somewhat more promising in babies with eczema.
Raising awareness of guidelines and changing practice: should we do more?
Timely introduction of peanuts into a child’s diet remains the only evidence-based strategy to reduce the risk of developing a peanut allergy. It remains important that all parents are aware of the current advice and feel confident when introducing peanuts to their babies. This is especially the case for those babies who are at higher risk of developing a peanut allergy because they have eczema, especially eczema that starts in early childhood or is severe.
It is also essential to publicize infant feeding guidelines in culturally and linguistically diverse populations. We showed that parents born in Asia were less likely to introduce peanut to their babies in the first year of life, and babies born to Asian parents have a higher risk of developing food allergies (here and here). Project Nip Bub, an initiative of the National Allergy Strategy, was developed to disseminate infant feeding guidelines to parents, GPs and mother and child health nurses, and has advice for introducing allergenic foods to infants, with the development of resources for culturally and linguistically diverse populations. currently in progress.
It is also possible that more regular consumption of allergenic foods once introduced may help prevent food allergy, although evidence is limited. Current recommendations suggest that, once introduced, these foods should continue to be included in the baby’s diet at least twice a week.
It is also important that parents are reminded to introduce peanut products in a form that is safe for infants to consume. Whole nuts are dangerous to babies and young children because they present a choking hazard. The frequency of nut inhalation in Melbourne increased over the past decade, although this was still an uncommon occurrence.
What else can be done to prevent peanut allergy?
Current evidence indicates that more will need to be done to prevent the development of peanut allergy, even if optimal introduction of allergenic foods to infants during the first year of life can be implemented for all babies. Some infants will develop peanut allergy despite early introduction of peanuts, and some infants will develop peanut allergy before they are developmentally ready to introduce peanuts into their diet.
As a result, other strategies for food allergy prevention are currently being investigated. Several large-scale randomized controlled trials are being tested in Australia, including the role of maternal consumption of allergenic foods (egg and peanut) during pregnancy and breastfeeding and a trial of infant vitamin D supplementation for the prevention of allergies.
The results of these trials are expected in the next 2-3 years. Continuing to recommend the introduction of peanut during the first year of life is critical to reducing the prevalence of peanut allergy in the population, as well as the development of additional prevention strategies for infants who do not benefit from introduction peanut precocious, and we look forward to the results of these and others. trials of new food allergy prevention strategies.
Associate Professor Jennifer Koplin is Head of the Childhood Allergy Group at the University of Queensland’s Center for Child Health Research and an Honorary Fellow of the Murdoch Children’s Research Institute.
Associate Professor Rachel Peters leads the epidemiology stream of the Murdoch Children’s Research Institute’s Population Allergy Research Group. His research program focuses on the epidemiology of allergic diseases.
Dr Victoria Soriano is a postdoctoral researcher at the Murdoch Child Research Institute, having recently completed her PhD in epidemiology at the University of…