Clinical Context

Food allergy is a common and potentially dangerous diagnosis among children, and the authors of the current study describe a radical change in thinking in the prevention of food allergy during the past 15 years. Previous guidelines recommended that parents avoid more allergenic foods during infancy and early childhood, but data that the early introduction of allergenic foods could actually reduce the risk for subsequent food allergy reversed some of these guidelines.

A systematic review and meta-analysis by Ierodiakonou and colleagues assessed the effects of consuming allergenic foods during infancy, and the results of this study were published in the September 20, 2016, issue of JAMA.^[1] The current study examines how peanut introduction during infancy might affect rates of peanut sensitization.

Study Synopsis and Perspective

Introducing peanut to children in their first year of life may not affect their likelihood of developing peanut allergy, a population-based study conducted in Australia suggests.^[2]

The prevalence of peanut allergy among infants at 12 months did not change, despite a large increase in parents introducing the food early to infants, the researchers report.

"In cross-sectional analyses, introduction of a guideline recommending early peanut introduction in Australia was not associated with a statistically significant lower or higher prevalence of peanut allergy across the population," lead study author Victoria X. Soriano, PhD, and coauthors write in JAMA.

To analyze potential changes in rates of peanut allergy over time, Dr Soriano, from the Centre for Food and Allergy Research of Murdoch Children's Research Institute in Parkville, Victoria, Australia, and colleagues compared the prevalence of peanut allergy between 2 cohorts of infants recruited at immunization centers in Melbourne.

They used the same sampling frame and methods in 2 periods roughly a decade apart: 5276 infants in the 2007 to 2011 group and 1933 infants in the 2018 to 2019 group. The 2 groups represent before and after samples to assess the effect of the 2016 Australasian Society of Clinical Immunology and Allergy guidelines that advised introducing peanut before 12 months of age to prevent peanut allergy. Earlier guidelines had advised avoiding allergenic foods until ages 1 to 3 years.

Both groups enrolled infants, regardless of immunization status, at their 12-month immunization visit. Ages hovered around 12 to 13 months, and males and females were equally represented.

All infants underwent a peanut skin-prick test, and those who developed a 1-mm or larger wheal were given open oral food challenges. Parents completed questionnaires covering demographics, food allergy risk factors, peanut introduction, and reactions.

Prevalence estimates were standardized to account for changes in population demographics over time. Between the 2 testing periods, the percentage of infants in the study of East Asian ancestry, who are known to be at increased risk for peanut allergy, rose from 10.5% to 16.5%.

Experts Recommend Introducing Infants to Peanut

Parents should carry on introducing their infants to peanuts while research in this area continues, several experts not involved in the study advise.

David R. Stukus, MD, director of the Food Allergy Treatment Center at Nationwide Children's Hospital in Columbus, Ohio, wants members of the healthcare team to encourage parents to introduce peanut and other allergenic foods into their infants' diets. "The worldwide adoption of new guidelines to introduce peanut to infants was based on only a few studies, so it is important to continue to monitor whether this approach is making a difference on a population level," he mentioned. 

"These results definitely do not undermine the theory that early introduction helps prevent peanut allergy, but it does suggest that early introduction, at least as currently practiced, may not be a magic bullet that eliminates peanut allergy in the overall population," Corinne Keet, MD, PhD, vice-chair of research in pediatrics at UNC (University of North Carolina) Health in Chapel Hill, told Medscape Medical News.

Matthew Greenhawt, MD, director of the Food Challenge and Research Unit at Children's Hospital Colorado in Aurora, pointed out that population-level changes in prevalence take time.

"This is part of a larger ongoing study, where additional data regarding these trends are anticipated," Dr Greenhawt explained. "This research group has a well-established population-level sampling frame and methodology to examine the development of food allergy, using ingestion challenge and clinician-observed reactions, making their cohort among the most robustly defined in the world."

Christina E. Ciaccio, MD, section chief of pediatric allergy and immunology at University of Chicago Medicine in Illinois, told Medscape Medical News, "This paper demonstrated that the creation of guidelines was not enough to reduce peanut allergy across the population. We providers need to work with families to encourage early introduction.”

In an accompanying editorial, Jennifer Dantzer, MD,  and Robert A. Wood, MD, from the Division of Allergy, Immunology, and Rheumatology in the Department of Pediatrics at the Johns Hopkins University School of Medicine in Baltimore, Maryland, write that the results provide important insights.^[3]

They recommend further related research and add that, "in the interim, given the potential for benefit and the low risk of harm, the results of this important study should not dissuade clinicians from following current consensus guidance that recommends early peanut introduction for infants."

Dr Soriano, Dr Stukus, Dr Keet, Dr Greenhawt, Dr Ciaccio, and Dr Dantzer report no relevant financial relationships. Several study authors and Dr Wood report financial relationships with the pharmaceutical industry.

Clinical Implications

• In a previous meta-analysis, early introduction to eggs at ages 4 to 6 months was associated with a risk ratio of 0.56 (95% CI, 0.36-0.87) for incident egg allergy. However, the timing of gluten introduction in the diet did not affect the risk for celiac disease, and the evidence that early sensitization to fish could reduce fish allergy was weak. There was moderate certainty based on low-quality evidence that the introduction of peanuts between 4 and 11 months could reduce the risk for subsequent peanut allergy.
• The current study did not find that increased rates of introduction of peanuts during infancy improved the risk for peanut allergy across the broad population. Early peanut introduction was associated with lower rates of peanut allergy among persons of Australian descent, but not among high-risk children of East Asian ancestry.
• Implications for the healthcare team: The healthcare team should continue to provide evidenced-based education to parents on peanut allergy along with information from the current study that the early introduction of peanuts during infancy may not reduce the risk for peanut allergy in all children.

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