"Allergens" Excerpt from Cribsheet by Emily Oster

Health economist and author Emily Oster shares an excerpt on allergens from her best-selling book Cribsheet: A Data-Driven Guide to Better, More Relaxed Parenting from Birth to Preschool.


“The story at the start of this chapter gives a sense of how the recommendations for peanuts have changed: introduce early, not later. What the story doesn’t convey is whether this translates more generally to allergenic foods, and exactly how you are supposed to introduce them.

On the first question, the answer is probably yes. The vast majority of allergies result from eight food types: milk, peanuts, eggs, soy, wheat, tree nuts, fish, and shellfish. The incidence of these allergies has grown over time, perhaps as a result of better hygiene (so less allergen exposure early on), and clearly due in part to a lack of early introduction.

Milk, eggs, and peanuts make up a large share even of these. We covered the peanut evidence earlier. Other research suggests a similar mechanism is at work for eggs and milk. The evidence on milk isn’t as convincing as the other two, but perhaps only because large studies have not yet been released.

All this points to the possible importance of introducing all these allergens early--probably as early as four months. (Milk can be introduced in the form of yogurt or cheese.)

Importantly, although the language here is about “introduction,” these studies include regular exposure as well. It is not enough to have your kid try peanut butter or eggs. You need to actually keep giving it to them regularly.

Which leads to the question: How?

This is a setting in which going slowly is a good idea. Try a little bit at first--only one allergenic food in a given day--and see how they react. If nothing, give them a little bit more. And so on until you get up to a normal amount.

And then keep these foods in the rotation.

This is a lot, especially since most babies don’t really eat much food anyway. To consistently expose them to peanuts and yogurt and eggs on top of everything else (what about the peas?) requires some logistical work. If you are daunted, and especially if you’re very concerned about these issues, there are some (new) products that contain powdered forms of these foods and are meant to be mixed with breast milk, formula, or cereals.”

Introduce Allergens Safely and Easily with Ready. Set. Food!

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These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure or prevent any disease.  If your infant has severe eczema, check with your infant’s healthcare provider before feeding foods containing ground peanuts.