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

For years, parents were told to wait until their child was two or three before giving them peanut butter. It seemed like the safest move-after all, peanut allergies can be deadly. But that advice, once backed by the American Academy of Pediatrics, actually made things worse. Between 1997 and 2010, peanut allergies in U.S. kids more than quadrupled. What no one realized then was that keeping peanuts away wasn’t protecting kids-it was setting them up to react.

The Turning Point: What the LEAP Study Changed

Everything shifted in 2015 with the release of the Learning Early About Peanut Allergy (LEAP) study. Led by Dr. Gideon Lack at King’s College London, this landmark trial followed over 600 high-risk infants-those with severe eczema or egg allergy-from infancy to age five. Half were given peanut-containing foods regularly starting at 4 to 6 months. The other half avoided peanuts entirely.

The results were shocking: by age five, only 1.9% of the group that ate peanuts developed an allergy. In the group that avoided them? 13.7%. That’s a 86% drop in allergy risk. It wasn’t a small effect. It was a revolution.

The National Institute of Allergy and Infectious Diseases (NIAID) quickly updated its guidelines in 2017, and since then, 26 major medical groups-including the AAP-have adopted the same approach. The message is clear now: early exposure isn’t risky. It’s preventive.

How to Introduce Peanuts Based on Risk Level

Not all babies need the same approach. The current guidelines divide infants into three risk groups:

• High-risk: Babies with severe eczema, egg allergy, or both. These kids should be evaluated by a doctor or allergist between 4 and 6 months. If allergy tests come back negative, they start eating 2 grams of peanut protein-about 2 teaspoons of smooth peanut butter-three times a week. The first dose is often given in a clinic for safety.
• Moderate-risk: Babies with mild to moderate eczema. No testing is needed. Just start introducing peanut-containing foods around 6 months, at home, following the same 2-gram, three-times-a-week rule.
• Low-risk: Babies with no eczema or food allergies. Introduce peanut whenever you start solids-usually around 6 months. No special steps needed.

The key is consistency. One snack won’t do it. You need to keep giving peanut protein regularly-three times a week-for months. The LEAP study used 6 grams per week, split into three doses. That’s about 21 peanuts total, spread out. Today, most parents use smooth peanut butter mixed with warm water, breast milk, or formula to make it safe and easy to swallow.

What Forms of Peanut Are Safe?

This is where parents get confused. Whole peanuts? Never. They’re a choking hazard. Peanut butter with chunks? Too risky for babies under one. The safest options are:

• Smooth peanut butter thinned with water, breast milk, or formula
• Peanut powder mixed into pureed fruits, vegetables, or infant cereal
• Spoonable peanut butter pouches (designed for babies, low-sugar, no added salt)
• Bamba (a puffed corn snack with peanut, popular in Israel and now available in the U.S.)

Avoid crunchy peanut butter, whole peanuts, or peanut pieces until your child is at least four years old. Safety matters as much as timing.

Why Early Introduction Works-And Why Delaying Doesn’t

The science behind this isn’t just about exposure. It’s about training the immune system early, before it learns to see peanut as a threat. When a baby’s gut and skin barrier are still developing, introducing peanut protein helps the body recognize it as food-not a danger.

Studies since LEAP have confirmed this. A 2023 meta-analysis of LEAP and the EAT study found that babies who ate peanut before six months had up to a 98% lower chance of developing an allergy-if they stuck to the plan. Even in the real world, where not everyone follows perfectly, the risk dropped by 75%.

Compare that to the old way: waiting until age two or three. That strategy didn’t just fail-it made allergies more common. The U.S. saw a steady climb in peanut allergies from 0.4% in 1997 to 2.0% in 2010. Since 2017, as guidelines spread, rates have started to drop. By 2023, peanut allergy prevalence fell to 1.6% in children, meaning about 300,000 fewer kids are affected than if we’d kept doing nothing.

Oral Immunotherapy: Treatment, Not Prevention

Don’t confuse early introduction with oral immunotherapy (OIT). They’re completely different.

Early introduction is for babies who don’t have a peanut allergy yet. It’s prevention.

OIT is for kids who already have a diagnosed peanut allergy. It involves giving tiny, carefully increasing doses of peanut under medical supervision to build tolerance. It’s not a cure. It’s a way to reduce the risk of a severe reaction if they accidentally eat peanut. OIT can cause side effects like stomach pain, vomiting, or even anaphylaxis during treatment. It’s not something parents should try at home.

The American College of Allergy, Asthma, and Immunology (ACAAI) is clear: OIT is not a substitute for early introduction. It’s a treatment for those who already have the allergy. Prevention is still the best strategy.

Barriers to Adoption-Why So Few Parents Follow the Guidelines

Despite strong evidence, most high-risk babies still aren’t getting peanut early. A 2022 study in Pediatrics found only 38.7% of high-risk infants were introduced to peanut by age 12 months. Why?

• Parental fear: 62% of parents in one survey said they were too scared to try.
• Confusion: Many don’t know how much peanut protein to give or what form to use.
• Doctor gaps: A 2023 survey found only 54% of pediatricians correctly recalled the current guidelines.
• Disparities: Black and Hispanic infants are 22% less likely to get early peanut exposure than White infants, contributing to ongoing allergy rate gaps.

The solution? Better education. Pediatricians need to talk about peanut introduction at the 4-month checkup-not wait until the 6-month visit. Pediatricians should offer to write down instructions: “Give 2 tsp smooth peanut butter, mixed with water, 3 times a week.” Simple. Clear. Actionable.

What About Other Allergens?

Peanut isn’t the only food that can trigger allergies. Egg, milk, soy, and tree nuts are common too. The EAT study showed that introducing multiple allergens early-peanut, egg, milk, fish, sesame, and wheat-also reduced the risk of multiple food allergies. It’s not just about peanut. It’s about building tolerance early across the board.

But peanut remains the strongest case. It’s the most common cause of fatal food reactions. And the data for early introduction is the most consistent. Other strategies-like taking probiotics or vitamin D during pregnancy-have been studied and shown no real benefit. The only proven method? Feeding peanut early.

What’s Next? The Future of Prevention

Researchers are already looking ahead. The PRESTO trial, funded by NIAID and running until 2026, is testing whether even earlier exposure-starting at 3 months-works better for the highest-risk babies. Another study is exploring whether heated peanut powder (which changes the protein structure) might be even safer and more effective.

Long-term follow-up from the LEAP study shows the protection lasts. Kids who ate peanut early and then stopped for a year still didn’t develop allergies. That suggests real immune tolerance-not just temporary desensitization.

Industry is catching up too. Peanut baby foods have grown 27% a year since 2018. More products are designed specifically for safe, early introduction. And with the FDA now requiring clearer allergen labeling, parents have better tools to make smart choices.

Bottom Line: Don’t Wait. Start Early.

If your baby has severe eczema or egg allergy, talk to your doctor by 4 months. Get tested if needed. Then start giving peanut protein three times a week.

If your baby has mild eczema, start at 6 months. No test needed.

If your baby has no risk factors, just introduce peanut like any other solid food-around 6 months.

Don’t use crunchy peanut butter. Don’t give whole peanuts. Don’t wait until they’re two. The window for prevention is narrow-and it’s open right now.

The data doesn’t lie. Early introduction works. It’s safe. It’s simple. And it’s saving lives.