New data expands upon the growing perception that allergenic food introduction early in a child’s life may lessen the possibility of allergy developments.
Earlier introduction of different allergenic food products within the first year of a child’s life may lead to less risk of food allergy development but also a high withdrawal rate from interventions, according to new findings.1
Food allergy is an important public health concern due to significant quality-of-life as well as economic elements, and incidence is known to vary between populations. The newfound understanding that early egg or peanut introduction to infants’ diets likely diminishes risk of allergy to both products has affected efforts for primary prevention.
Now, early introduction of allergenic food products has become recommended in clinical practice guidelines.2 This new study was conducted to further examine whether introduction of allergenic foods early on affects overall prevalence of food allergy.
The research was authored by Robert J. Boyle, MD, PhD, from the National Heart and Lung Institute at the Imperial College London. Boyle and his fellow investigators set out to assess outcomes in an update of a prior systematic review and meta-analysis.
“We evaluated the association between earlier allergenic food introduction and risk of any food allergy and evaluated rates of withdrawal from the intervention as a marker of safety and acceptability of earlier allergenic food introduction,” Boyle and colleagues wrote.
The investigators conducted their systematic review and meta-analysis through searches on the Embase, Medline, and CENTRAL databases.
They searched for articles related to infants and randomized controlled trials evaluating the impacts of common allergenic food introductions on the development of immunoglobulin E (IgE)-mediated allergies to food between 1 - 5 years of age.
The team’s searches used the timeframe between each database’s inception up until December of 2022, with relevant search terms utilized. They had multiple authors independently screen articles to determine eligibility.
The researchers later extracted data in duplicate and then analyzed through the use of a random-effects model, with the certainty of evidence evaluated by using the Grading of Recommendations, Assessment, Development, and Evaluation framework.
The investigators sought to assess 2 primary outcomes: the risk of developing IgE-mediated allergies to any foods in infants who were between the ages of 1 - 5 years and withdrawal from the food interventions.
The secondary outcomes the research team assessed included allergy to specific foods. Following a screening of 9283 titles, 23 trials were deemed by the team to be eligible, with a total of 56 articles and 13,794 randomized participants from which data was drawn.
Overall, the investigators’ results showed that introducing multiple allergenic foods between 2 and 12 months of age could, in fact, reduce the risk of food allergy. This was according to moderate-certainty evidence from 4 studies involving 3295 participants (risk ratio [RR], 0.49; 95% CI, 0.33 - 0.74; I2 = 49%).
However, the team also noted that they found moderate-certainty evidence from 5 studies with 4703 participants in their analysis which indicated that introduction of multiple allergenic foods during the same period was associated with higher rates of withdrawal from the intervention (RR, 2.29; 95% CI, 1.45 - 3.63; I2 = 89%).
Additionally, the investigators acknowledged some high-certainty evidence from 9 studies involving 4811 participants that showed introduction of eggs from 3 - 6 months of age diminished the risk of egg allergies (RR, 0.60; 95% CI, 0.46-0.77; I2 = 0%).
They also reported high-certainty evidence from 4 studies with 3796 participants indicating introduction of peanuts from 3 - 10 months of age diminished the risk of peanut allergy (RR, 0.31; 95% CI, 0.19 - 0.51; I2 = 21%). That said, the team’s evidence for the cow's milk introduction timing and the risk of allergy to the milk was of low certainty.
“The findings support the concept of using earlier allergenic food introduction to prevent food allergy but highlight the need for more acceptable forms of multiple allergenic foods,” they wrote. “Notably, most complementary feeding interventions were initiated before 6 months of age, which is against World Health Organization infant feeding guidance.”