Peanut Allergy Prevention: When and How to Introduce Peanuts to Infants

By Lindsey Smith On 28 Nov, 2025 Comments (10)

For years, parents were told to wait until their child was two or three before giving them peanut butter. It seemed like a simple way to protect them. But by 2015, peanut allergies had more than quadrupled in just over a decade. Hospitals were seeing more kids with life-threatening reactions than ever before. Then came a game-changing study - the LEAP trial - that flipped everything upside down. What if the real danger wasn’t eating peanuts too early, but waiting too long?

Why Early Introduction Works

The old advice - delay peanut exposure - didn’t just fail. It made things worse. Between 1997 and 2010, peanut allergies in U.S. children jumped from 0.4% to 2.0%. That’s a 400% increase. Meanwhile, countries like Israel, where babies regularly eat peanut snacks like Bamba as early as 7 months, saw peanut allergy rates under 0.3%. The difference wasn’t genetics. It was timing.

The LEAP study, published in The New England Journal of Medicine in 2015, gave high-risk infants (those with severe eczema or egg allergy) peanut protein three times a week starting between 4 and 11 months. By age 5, only 3% of those kids developed peanut allergy - compared to 17% in the group that avoided peanuts entirely. That’s an 80% drop. Follow-up studies showed the protection lasted even after they stopped eating peanuts for a year. This wasn’t just temporary tolerance. It was real, lasting immunity.

Later, the EAT study confirmed these results across broader groups. When you combine both studies, the data shows a 98% reduction in peanut allergy among babies who stuck to the early introduction plan. Even babies with mild eczema saw an 85% drop. The window for maximum benefit? Before 6 months. After that, the protective effect weakens.

How to Introduce Peanuts Safely

Not all babies need the same approach. The NIAID guidelines (updated in 2017 and refined since) break it down into three risk levels:

High-risk: Severe eczema, egg allergy, or both. These babies should be evaluated by a doctor or allergist between 4 and 6 months. If allergy tests come back negative, start with 2 grams of peanut protein (about 2 teaspoons of smooth peanut butter) three times a week. The first dose should be given under medical supervision.
Moderate-risk: Mild to moderate eczema. No testing needed. Introduce peanut-containing foods at home around 6 months, three times a week.
Low-risk: No eczema or food allergies. Introduce peanut anytime after starting solids - usually around 6 months - as part of a varied diet.

Safe forms matter. Never give whole peanuts or chunky peanut butter - choking risk. Instead, mix 2 teaspoons of smooth peanut butter with 2-3 tablespoons of warm water, breast milk, or formula until it’s runny. You can also stir it into oatmeal, pureed fruit, or yogurt. Pre-made infant peanut products like spoonable pouches are also safe and convenient.

One dose equals about 2 teaspoons of peanut butter. That’s roughly 21 peanuts per week, split into three doses. Don’t overdo it - consistency matters more than quantity. And always introduce peanut when your baby is healthy, not sick or teething.

What Oral Immunotherapy (OIT) Is - and Isn’t

People often confuse early introduction with oral immunotherapy (OIT). They’re not the same. Early introduction is prevention. OIT is treatment.

OIT is for kids who already have a diagnosed peanut allergy. It involves giving tiny, increasing amounts of peanut protein daily under medical supervision, aiming to build tolerance so they don’t react to accidental exposure. It doesn’t cure the allergy. It just raises the threshold for a reaction. Many kids on OIT still carry the allergy and must keep carrying an epinephrine auto-injector.

Early introduction, on the other hand, aims to stop the allergy from forming in the first place. It’s like vaccinating against it. And it works better than any treatment ever could. The goal isn’t to manage peanut allergy - it’s to prevent it from ever happening.

Split image showing a baby with eczema versus a healthy child eating peanut, connected by a timeline of medical breakthrough.

Why So Few Parents Are Doing It

Despite strong guidelines, only about 39% of high-risk infants are getting peanut introduced early. Why?

Many parents are scared. They’ve heard horror stories. They worry about choking. They don’t know how to prepare peanut safely. Some doctors still give outdated advice - a 2023 survey found only 54% of pediatricians knew the current guidelines.

There’s also a gap in access. Black and Hispanic infants are 22% less likely to get early peanut introduction than White infants, according to a 2023 study. That’s not because of cultural preferences. It’s because of systemic barriers - lack of provider education, limited specialist access, and misinformation.

And then there’s the confusion. Some parents think if their baby has eczema, they should avoid all allergens. But eczema is a sign the immune system is already primed for allergy - making early peanut exposure even more critical.

What’s Changed Since 2017

The results are in. Since the guidelines changed, peanut allergy rates in U.S. children have dropped from 2.2% in 2015 to 1.6% in 2023. That’s over 300,000 fewer children with peanut allergies. Among high-risk kids with eczema, the drop was even steeper: 67% lower in severe cases, 87% in moderate.

Food companies responded. Peanut-containing infant foods grew 27% a year from 2018 to 2023. Pediatricians now have resources - handouts, videos, dosing charts - to help families. The FDA now requires clear allergen labeling on infant foods, making it easier to spot safe products.

But the biggest change? Mindset. Parents no longer see peanut as something to fear. They see it as something to offer - early, safely, and consistently.

Diverse toddlers eating peanut puree in a park, with protective energy lines and declining allergy rates in the sky.

What’s Next

Researchers are now testing whether introducing multiple allergens at once - peanut, egg, milk, tree nuts - gives even broader protection. Early data from the EAT extension study suggests it does. The NIAID-funded PRESTO trial, due to wrap up in 2026, will pinpoint the exact best age and dose for high-risk babies.

One thing is clear: the longer we wait, the harder it becomes to prevent allergy. The science isn’t just solid - it’s urgent. For every baby with severe eczema, the first 6 months are a window. Miss it, and you might be locking in a lifelong condition.

Real-World Tips for Parents

Start with smooth peanut butter - never chunky or whole nuts.
Use 2 teaspoons of peanut butter per serving, three times a week.
Wait 3 days between first introduction and next dose to watch for reactions.
Keep offering peanut regularly - even if you don’t see a reaction. Consistency builds tolerance.
If your baby has severe eczema or egg allergy, talk to your pediatrician before starting. Ask about allergy testing.
Don’t wait for “perfect” timing. If your baby is sitting up, showing interest in food, and can swallow purees - they’re ready.

There’s no magic formula. Just consistency. Just timing. Just courage to do what the science says - even when it feels scary.