A few years ago the prevailing wisdom was that babies at risk of allergies should avoid peanuts or peanut products until age 3 or older. The idea behind this restriction - which was based on American Academy of Pediatrics (AAP) guidelines released in 2000 - was that feeding peanuts too early to little ones might risk severe, possibly life-threatening allergic reactions.
Over the years that thinking has done a 180. Now, scientists believe the exact opposite: Giving your baby peanuts earlier rather than later might prevent them from developing an allergy.
On Thursday, the National Institute of Allergy and Infectious Diseases released formal, detailed guidelines for pediatricians and allergists.
Those at highest risk are defined as babies with severe eczema - a skin condition where patches of skin become inflamed, itchy, red and cracked - or egg allergy or both. Those in the middle group have mild-to-moderate eczema. And those in the lowest-risk group have no eczema or food allergies.
The number of American children with nut allergies has quadrupled in the past 13 years, and peanut allergies are now estimated to affect 2 percent of them.
The new thinking on peanut exposure grew out of observations of Israeli children in Israel versus Israeli children in Britain. In Israel parents often give various types of peanut preparations such as paste or nuggets in the very earliest days of a child's life. Scientists noted that the incidence of peanut allergies in Israeli children in Israel is lower than in Israeli children in Britain and wondered whether the two things could be related.
That theory was put to a test in the much-praised Learning Early About Peanut Allergy (LEAP) study, a randomized trial led by Gideon Lack of King's College London involving 640 infants considered at high risk of developing peanut allergies. The results, published in 2015 in the New England Journal of Medicine, showed that children at high risk who regularly consumed peanuts as infants had an 81 percent lower chance of developing a peanut allergy by age 5.
Similar studies are being conducted on early exposure to tree nuts and eggs, but results probably won't be available for a few more years.
Those children at highest risk should be exposed to peanuts earliest - at 4 to 6 months - and be referred to a specialist who might perform a blood or skin test before deciding how to handle their first exposure to peanuts.
Those in the middle group should be fed peanuts when they are about 6 months old. Those at lowest risk can have them at any time, also at home, but can typically start when they are about 6 months old, as well.
These guidelines are simply recommendations and that "your child dictates when they are ready for some foods. The same could be said of exposing kids to broccoli or fish.
Here's how to feed your infant, from the guidelines:
1. Prepare a full portion of a peanut-containing food such as peanut butter dissolved or thinned with water, peanut butter, peanut flour or powder mixed with a fruit or vegetable puree, a puffed maize snack with peanuts, which can be softened with water or not depending on the child's age or preferences.
2. Offer your infant a small part of the peanut serving on the tip of a spoon.
3. Wait 10 minutes.
4. If there is no allergic reaction after this small taste, then slowly give the remainder.
Introduce peanut-containing foods at an appropriate age and in accordance with family preferences and cultural practices.