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-until it wasn’t. Between 1997 and 2010, peanut allergies in U.S. children more than quadrupled, jumping from 0.4% to 2.0%. That spike didn’t stop. By 2015, nearly one in 50 kids had a peanut allergy, and it was becoming the leading cause of food-related anaphylaxis in children. Then came a breakthrough that flipped everything on its head.

Why Waiting Made Things Worse

The old advice-delay peanut exposure-was based on fear, not science. It came from a 1998 American Academy of Pediatrics recommendation that suggested avoiding peanuts in high-risk babies. But the data didn’t match the logic. As more parents avoided peanuts, more kids developed allergies. It was like trying to stop a fire by hiding the matches.

The turning point was the LEAP study, published in 2015. Researchers in London followed 640 high-risk infants-those with severe eczema or egg allergy-from 4 to 11 months old. Half were told to avoid peanuts entirely. The other half were given 2 grams of peanut protein three times a week, mixed into food or diluted peanut butter. 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 risk.

It wasn’t a fluke. The EAT study, which looked at peanut and other allergens in healthy infants, confirmed it. When peanut was introduced early-before six months-there was a 75% reduction in allergy development. Even more striking: in babies with mild or moderate eczema who stuck to the schedule, the reduction was nearly 100%.

What the Guidelines Say Now

In 2017, the National Institute of Allergy and Infectious Diseases (NIAID) released updated guidelines based on this evidence. They split infants into three risk groups, and each has a clear path:

• High-risk infants (severe eczema, egg allergy): Start peanut between 4 and 6 months, but only after seeing a doctor. They may need a skin or blood test first. If the test is negative, begin with a small amount under medical supervision, then continue with 2 grams of peanut protein three times a week.
• Moderate-risk infants (mild to moderate eczema): Introduce peanut around 6 months at home, no testing needed. Use smooth peanut butter mixed with water or breast milk.
• Low-risk infants (no eczema or food allergies): Introduce peanut anytime after starting solids, usually around 6 months. No special steps required.

The key? Don’t wait. The window for prevention is narrow. Waiting until 10 months or later cuts the protective effect in half. The earlier you start-between 4 and 6 months-the better.

How to Safely Introduce Peanut

Whole peanuts? Never. Choking hazard. Peanut butter straight from the jar? Too thick. The goal is to give 2 grams of peanut protein, three times a week, in a safe, swallowable form.

Here’s how:

1. Use smooth peanut butter-no chunks, no crunchy.
2. Mix 2 teaspoons (about 10 grams) of peanut butter with 2-3 tablespoons of warm water, breast milk, or formula until it’s thin and runny.
3. Or, stir it into infant cereal, pureed applesauce, or mashed banana.
4. Start with a tiny amount-a quarter of a teaspoon-and wait 10 minutes. Watch for swelling, hives, vomiting, or trouble breathing.
5. If no reaction, give the rest. Then continue three times a week.

Some parents use products like Bamba (a puffed corn snack with peanut) or pre-made peanut powder designed for infants. These are fine too. Just make sure you’re getting the right amount of peanut protein-about 2 grams per serving. Check the label or use a trusted calculator from a pediatric allergy center.

What About Oral Immunotherapy (OIT)?

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

Early introduction is for preventing allergy in babies who don’t yet have it. OIT is for treating kids who already have a confirmed peanut allergy.

OIT involves giving tiny, gradually increasing doses of peanut protein under strict medical supervision. It doesn’t cure the allergy-it builds tolerance. Kids on OIT must keep eating peanut daily for life, or the protection fades. Side effects like stomach pain, itching, or even anaphylaxis are common during treatment. It’s not for everyone. The FDA has approved one OIT product, Palforzia, for kids 4 to 17, but it’s expensive, requires frequent clinic visits, and isn’t a first-line recommendation for prevention.

For parents of babies without allergy, OIT isn’t needed. Early introduction is safer, simpler, and far more effective at stopping the allergy before it starts.

Why So Many Parents Still Wait

Even with clear guidelines, only about 39% of high-risk infants are getting peanut introduced early. Why?

Parents are scared. One 2022 survey found 62% of parents worried about anaphylaxis during the first taste. Doctors are unsure too. A 2023 study showed only 54% of pediatricians could correctly state the current NIAID guidelines.

There’s also confusion over what “safe” peanut looks like. Some parents give peanut flour, others use peanut oil (which doesn’t contain the protein that triggers allergy), and some think a smear on the lip is enough. It’s not. You need to feed it orally, regularly, and consistently.

And then there’s inequality. Black and Hispanic infants are 22% less likely to get early peanut exposure than white infants. That’s not just a gap-it’s a risk gap. Allergy rates remain higher in these communities, partly because prevention isn’t reaching them.

What Works-and What Doesn’t

Let’s clear up the noise. Not every parenting tip helps.

• Works: Early peanut introduction (4-6 months), consistent feeding (3x/week), smooth texture, medical guidance for high-risk babies.
• Doesn’t work: Avoiding peanuts during pregnancy or breastfeeding. No evidence. The Cochrane Review found no benefit.
• Doesn’t work: Probiotics or vitamin D supplements. Multiple studies show no effect on peanut allergy prevention.
• Doesn’t work: Waiting until toddlerhood. That’s the old advice-and it failed.

The science is clear: exposure, not avoidance, builds tolerance. The immune system learns to recognize peanut as safe when it’s introduced early and often.

Long-Term Results

One of the most powerful findings? The protection lasts. The LEAP study followed kids after they stopped eating peanut for a full year. Even after 12 months of avoidance, 80% of the kids who ate peanut early still didn’t have an allergy. That’s not just desensitization-it’s true tolerance. Their immune systems remembered peanut as harmless.

And the numbers are improving. In 2015, 2.2% of U.S. children had peanut allergies. By 2023, that number dropped to 1.6%. That’s about 300,000 fewer children with a life-altering allergy. The CDC says the biggest drop is in high-risk groups, especially those with eczema. In babies with mild eczema, peanut allergy dropped by 85%. In moderate eczema, by 87%.

What’s Next?

Researchers are now looking at combining early peanut introduction with other allergens. The EAT study extension showed that introducing peanut, egg, milk, and fish together before six months didn’t just lower peanut allergy-it lowered the risk of multiple food allergies at once.

The PRESTO trial, funded by the NIAID with $35 million, is testing whether even earlier exposure-starting at 3 months-works better for the highest-risk babies. Results are expected in 2026.

Industry is catching up too. Peanut powder blends, spoonable pouches, and infant-specific peanut products are booming. Sales grew 27% a year from 2018 to 2023. More parents are buying them. More doctors are recommending them.

But the biggest challenge isn’t the science. It’s the rollout. We have the tools. We have the data. What we need now is consistent messaging, better provider training, and equitable access.

What Parents Should Do Today

If your baby is 4 to 6 months old and has severe eczema or egg allergy: Talk to your pediatrician. Ask about allergy testing. If it’s negative, start peanut at home or under supervision.

If your baby has mild eczema: Start peanut at 6 months. No test needed. Mix smooth peanut butter with water or formula. Give it three times a week.

If your baby has no eczema or food allergies: Just introduce peanut like any other solid food. No special rules.

Don’t wait. Don’t overthink it. The evidence is strong, simple, and life-changing.