The first year as a parent comes with a lot of questions about timing. When will baby start rolling over? How about sleeping through the night? Which immunizations do babies need and when? And when it comes to the topic of food, the question of introducing potential food allergens is a big one.

Below, we explain when to begin introducing common food allergens to your child, key factors to be aware of and when to get a doctor if you suspect food allergies are involved.

Babies should be introduced to food allergens early

In the past, it’s been recommended that parents wait as long as a year or two before introducing food allergens to their babies. However, recent studies have shown that this doesn’t actually have any protective effects. In fact, these newer studies suggest that early, regular exposure to an allergenic food (such as milk, eggs, peanuts, tree nuts, soy, wheat or seafood) may actually prevent the development of the associated allergy, even in babies with a heightened allergy risk.

That said, introducing allergens always carries the risk of an allergic reaction. The safest approach is to consult with your child’s pediatrician to make sure you have all the information you need before you begin. If your baby is at a higher risk for food allergies, a pediatrician might recommend an allergy evaluation or specific methods for introducing certain allergens.

Which babies are at the highest risk of allergies

Allergies can run in families. So if you, your baby’s other parent or a sibling of your baby has an allergy, your baby would be considered to have a slightly increased risk for developing a food allergy.

The strongest risk factor for food allergies is if your baby has or has had eczema or an immediate allergic reaction to any food, including reactions to breast milk as a result of your breastfeeding diet. 40-50% of children in the United States with a food allergy have allergies to multiple foods.

When you can introduce food allergens to your baby

With a pediatrician’s go-ahead, you can start introducing allergens into your baby’s diet once they’ve tolerated a few different foods (such as infant cereal and mashed or pureed fruits and vegetables). A baby is generally ready to start trying foods other than breast milk or baby formula between 4-6 months old, when they:

  • Can sit up, with or without support
  • Have good control of their head and neck
  • Grab for objects and bring them toward their mouth
  • Move food to the back of their tongue to swallow

How to introduce allergens into a baby’s diet

There are well-established strategies for introducing allergens. But again, make sure to talk to your child’s pediatrician before you start. They’ll give you recommendations specifically for your baby.

1. Start small

When introducing allergenic foods to a baby, use small amounts and choose one to introduce at a time. This minimizes the risk to your baby and can make it easier to tell if that food is the cause of a reaction. For example, you could start by mixing 1/4 teaspoon (tsp) of smooth peanut butter or a well-cooked egg into your baby’s regular food.

2. Give it time

It can be helpful to give your baby allergen-containing food for their first meal of the day, because allergic reactions can take up to around two hours to show up. If your baby doesn’t react to the initial dose, increase the amount gradually (such as by another 1/4 tsp) in each following serving. If there’s still no reaction after 3-5 days, you can start testing a different food allergen. However, it’s important to keep giving your baby any food allergens they don’t react to 2-3 times per week to maintain their tolerance.

If your baby appears to react to a new food, stop giving them that food immediately. If the reaction is mild, call your baby’s pediatrician to find out next steps. If the reaction appears severe or is affecting your baby’s breathing, call 911.

Symptoms of a mild allergic reaction in a baby can include:

  • Hives
  • Welts
  • Rashes

A moderate allergic reaction in a baby can include those symptoms above, along with:

  • Swelling of the lips, eyes or face
  • Diarrhea or vomiting
  • Changes in behavior (such as suddenly becoming very fussy)

Symptoms of a severe allergic reaction in a baby include:

  • Swelling of the throat or tongue (which may cause drooling)
  • Difficult or wheezy breathing
  • Coughing
  • A change or difficulty with vocalizing or crying
  • Pale skin
  • Limpness

Need more guidance around baby allergies? Talk to an expert

Knowing whether your child has food allergies – and if they do, which ones – is a necessary part of being a parent. It’s information that helps you keep your child safe and comfortable as they grow up and explore the world around them.

So, if you have any questions or concerns about your baby’s risk for allergies or how to test for them, talk to a kids’ health expert like your pediatrician. They can look at your child’s family and medical histories, make initial recommendations and refer you to an allergist if necessary.