Early Introduction of Peanuts Led to Significant Decline in Allergies

• Peanuts are one of the most common causes of potentially lethal food allergies.
• Evidence suggests that early introduction of certain foods can help prevent allergies.
• A new study confirms that these recommendations are actually reducing food allergies.
• Doctors say early introduction of peanuts is recommended for all infants ages 4 to 6 months.

Peanut allergy is one of the most common causes of severe allergic reactions, such as anaphylaxis, in children. Anaphylaxis can be fatal if not treated quickly, making the prevention of food allergies essential.

Prior evidence has suggested that early introduction of certain foods, like peanuts, in an infant’s diet can help prevent food allergies.

After pediatricians began encouraging parents to introduce peanuts — and later, other allergenic foods — during infancy, rates of peanut and overall food allergies in young children dropped significantly in recent years.

A large new study of medical records from tens of thousands of children across the United States indicates that this advice has made a real-world difference. The findings were published on October 20 in Pediatrics.

Immunoglobulin E-mediated food allergy (IgE-FA) is an immune system reaction to a specific food protein, such as in peanuts. Peanuts are one of the most common causes of IgE-FA.

The new study focused on diagnoses of IgE-FA and on atopic dermatitis (eczema), which often signals a higher allergy risk.

To conduct the study, researchers at the Children’s Hospital of Philadelphia, in collaboration with the American Academy of Pediatrics (AAP) Comparative Effectiveness Research through Collaborative Electronic Reporting (CER²) network, analyzed electronic health records from 48 pediatric practices nationwide.

These included 31 practices connected to an academic health system in the mid-Atlantic region and 17 independently owned offices across other states.

The team examined three distinct time periods to see how allergy rates changed over time:

• Before the guidelines (Sept 2012–Oct 2014) — This was before early peanut introduction became standard practice.
• After the initial guidelines (Sept 2015–Aug 2017) — The first recommendations targeted high risk infants (those with severe eczema or egg allergy).
• After the expanded recommendations (Feb 2017–Jan 2019) — The advice was broadened to include more infants and included new guidance on allergy testing and risk levels.

Each child in the study was tracked from birth to age 3, with at least one primary care visit before their first birthday.

To confirm food allergy cases, the team used a combination of medical codes, documented allergies in the electronic health record, and prescriptions for epinephrine auto-injectors, a treatment used to rapidly open up a person’s airway during anaphylaxis.

Statistical models helped account for differences in age, sex, race, and ethnicity.

The researchers also conducted an “interrupted time series” analysis, a method that identifies shifts in trends before and after major policy changes — in this case, the introduction of new feeding guidelines.

After the early introduction guidelines were published, the proportion of young children diagnosed with peanut allergies fell sharply.

In the two-year observation period, peanut allergy rates dropped from 0.92% before the guidelines to 0.67% afterward, amounting to a 27% decrease.

When the researchers looked at one-year observation windows and included data after the addendum guidelines, the drop was even greater: peanut allergy rates fell from 0.79% to 0.45% — a 43% decrease.

Also, the declines weren’t limited to peanuts. Across all allergenic foods, rates of any IgE-mediated food allergy dropped. In the two-year analysis, overall food allergy diagnoses fell from 1.98% to 1.23%, a 38% reduction.

In the one-year analysis, the rate went from 1.46% to 0.93%, a 36% drop.

When adjusted for age, sex, race, and ethnicity, children in the post-guideline periods were significantly less likely to be diagnosed with peanut or any food allergy compared to those born before.

The hazard ratio showed around a 35% lower risk for peanut allergy. Rates of occurrence also showed a 31% lower risk for any food allergy after the guidelines were introduced.

It was also noted that the drop in peanut allergy rates was seen in children with and without eczema. According to the authors, this suggests that the benefits of early peanut introduction may extend beyond the “high-risk” group for which the advice was originally intended.

Additionally, in one sub-analysis, children who already had egg allergies were less likely to develop peanut allergies after the guidelines took effect, while children with eczema did not show a significant change.

The types of food allergies also shifted. Before the guidelines, peanut was the most common allergen, followed by egg and cow’s milk. After the guidelines, egg moved into the top spot, peanut dropped to second, and cow’s milk allergy rates fell significantly.

The interrupted time series analysis revealed a clear downward trend in food allergy diagnoses after the guidelines were released. And, while the specific decline in peanut allergy rates was less dramatic in this model, the overall trajectory still showed improvement.

The researchers also noted changes in which children were being diagnosed. After the guidelines were published, a greater proportion of very young infants (under four months) were represented among those diagnosed with food allergies.

Demographic patterns also shifted slightly. After the guidelines, a smaller proportion of food-allergic children were Black, Asian, or Pacific Islander, or Hispanic, compared with earlier years.

Overall, the researchers say the findings suggest that early introduction of allergenic foods, especially peanuts, is becoming more common in everyday pediatric practice and may already be helping to lower allergy rates across the U.S.

Amiirah Aujnarain, MD, a board certified pediatrician, allergist, and immunologist, said peanut-containing foods can be introduced when your baby is developmentally ready for solids, which is generally around 6 months, but not before 4 months. Aujnarain wasn’t involved in the new study.

“For infants at high risk of peanut allergy (such as those with severe eczema or an existing egg allergy), the recommendation is to consider introducing peanut as early as 4 to 6 months, after ensuring readiness and in a safe form, and ideally in consultation with a healthcare provider,” she told Healthline.

If your child is at low to moderate risk (no severe eczema or egg allergy), you can feed them peanut-containing foods around 6 months of age without obtaining allergy screening beforehand, added Aujnarain.

“Once peanut‐containing foods are introduced, it’s recommended to continue regular ingestion (for example, a few times per week) to maintain tolerance of at least two teaspoons in each serving,” she said.

Aujnarain additionally noted the importance of using non-choking forms of peanut products, for example, smooth peanut butter thinned out, rather than whole peanuts or thick peanut butter.

Michael Pistiner, MD, MMSc, pediatric allergist representing Allergy & Asthma Network, said he finds the decline in peanut allergies “both reassuring and encouraging.” Pistiner wasn’t involved in the study.

He further noted that parents can also introduce other common allergens, such as egg and cow’s milk, to babies around the same timeframe: 4 to 6 months of age.

“For the majority of infants, this can be done safely at home without prior testing,” said Pistiner. “Families should then keep these foods in the infant’s diet routinely.”

He further explained that fewer than 5% of babies are considered to be at high risk for food allergies. However, it is important to target the 4- to 6-month window for early introduction of food allergens in these children.

“Early discussion with the child’s primary care clinician can help ensure peanut and other allergenic foods are introduced safely and without delay,” said Pistiner.

“Overall, early introduction, rather than delay, is now the recommended approach for all infants, as it supports immune tolerance and long-term nutrition,” he concluded.