Can feeding babies peanuts prevent allergies?
A study published in the New England Journal of Medicine strengthened evidence that feeding children peanuts early helps them avoid peanut allergies. If children at increased risk of developing an allergy were introduced to peanuts in the first year of life and continued eating them, their risk of becoming allergic decreased. If they ate peanuts until age 5 and then stopped eating them for a year, the break didn't increase their chance of becoming allergic, the study showed. Dr. Todd Green, an associate professor of pediatrics in Children's Hospital of Pittsburgh of UPMC's Division of Pulmonary Medicine, Allergy & Immunology, takes our questions.
How can I safely find out whether my baby is allergic to peanuts?
The best test to see whether someone is allergic to a food is to eat the food. We don't generally recommend allergy testing (with skin or blood testing) if there is nothing to suggest that a person is allergic, since allergy tests, while very helpful, are not perfect, and it is not uncommon for young children in particular to test “positive” to a food even when they are not allergic. There are exceptions to this rule, and if parents are concerned about a possible peanut allergy in their baby they should discuss with their allergist, but it is important to understand that we do not recommend widespread “screening” of babies for peanut or other allergies with any type of testing.
Can I really prevent my baby from becoming allergic to peanuts?
We are still learning about this. A study released in 2015 demonstrated convincingly that among babies at risk for peanut allergy (based on a history of egg allergy or severe eczema), those with skin testing results that suggested they were not allergic were significantly less likely to become allergic if they introduced peanut before age 1 than if they waited until age 5. It should be emphasized that this study did not apply to all children, only those with the peanut allergy risk factors mentioned, and that these infants were first tested and then only introduced peanut if the test result was encouraging. In this population of children, however, early introduction of peanut seemed to be remarkably effective.
Can other allergies be avoided by early exposure?
The answer to this is not clear. As mentioned above, in certain “high risk” babies not already allergic, early exposure to peanut does seem to decrease the risk of developing peanut allergy. The results among infants in general and regarding other types of food allergies are not as clear. What does seem to be apparent, however, is that delayed introduction as a widespread rule (as was recommended at the beginning of this century) does not seem to prevent allergy.