Why introducing peanut early lowers allergy risk (the LEAP study)
The old 'delay peanuts' advice was reversed. The LEAP study found early peanut introduction cut peanut allergy by about 80% in high-risk infants.
This is one of the biggest reversals in modern infant-feeding guidance. For years parents were told to delay peanuts. The LEAP study (2015) tested that logic directly and found that introducing peanut early cut peanut allergy risk by roughly 80% in high-risk infants. The immune system appears to learn tolerance through early, regular exposure; avoidance was training it to treat peanut as a threat.
Current guidance is to introduce peanut-containing foods around 4–6 months in an age-appropriate form — thinned smooth peanut butter stirred into purée, or peanut puffs softened. Never whole peanuts or thick spoonfuls of butter; there the risk is choking, not allergy.
Two important caveats. If your baby has severe eczema or an existing egg allergy, talk to your pediatrician before the first exposure. And introduce one new allergen at a time, then watch for a couple of hours — hives, swelling, vomiting or any breathing change means seek help immediately.
See also the peanut butter food guide and the allergen introduction guide.
Based on NIAID/AAP guidelines and the LEAP study (NEJM, 2015).
Frequently asked questions
When should I introduce peanut to my baby?
Around 4–6 months, once your baby is developmentally ready for solids, in an age-appropriate form such as thinned smooth peanut butter — not whole peanuts or thick spoonfuls, which are choking hazards.
What did the LEAP study show?
The 2015 LEAP study tested early introduction against avoidance in high-risk infants and found early, regular peanut introduction reduced peanut allergy risk by roughly 80%. Early exposure appears to help the immune system learn tolerance.
Are there babies who should see a doctor first?
Yes. Babies with severe eczema or an existing egg allergy are higher-risk and should be assessed by a pediatrician or allergist before their first peanut exposure; some warrant supervised introduction.
Guidance, not medical advice — always supervise feeding and consult your pediatrician.