Babies should be given peanut early - some at four months old - in order to reduce the risk of allergy.
Studies have shown the risk of peanut allergy can be cut by more than 80% by early exposure.
However, young children should not eat whole peanuts, because of the risk of choking.
Children with other allergies or severe eczema should start on peanut-containing foods at between four and six months old, with medical supervision
Babies with mild eczema should have peanut-containing food at about six months old
Those with no eczema or allergies can have peanut-containing food freely introduced
The National Institute of Allergy and Infectious Diseases said the new guidance was "an important step forward".