Introducing Allergens to Babies

After a groundbreaking study demonstrated that the early introduction of peanuts to babies at risk of developing allergies could prevent peanut allergy from developing by as much as 81%, modern allergists and medical institutions now recommend that allergens be introduced before a baby’s first birthday.1 In other words, delaying the introduction of common allergens may actually increase the likelihood of allergies developing.2

Is my baby at risk of food allergies?

Before you introduce the major food allergens, it’s important to know if your baby is at risk of developing food allergies. A food allergy can develop at any point in a person’s life, but there are certain risk factors that you may be able to spot early on.

First, if your baby has eczema, which tends to present as dry patches on the skin, your baby is at an increased risk of developing food allergies.3 Second, if your baby has had asthma or allergic rhinitis (hay fever), they are more likely to develop food allergies.4 Lastly if your baby has a family history of allergies or already has a sensitivity or allergy to other foods (such as dairy or eggs), the risk for developing food allergies is higher.5

If your baby has any of the above risk factors, it would be wise to work with a pediatric allergist early on in your solid food journey. Otherwise, aim to introduce the common food allergens between 6 and 12 month of age.

How to introduce allergenic foods to babies

Introducing food allergens doesn’t have to be terrifying. First, you can start with a scant amount of the allergen to minimize any reaction that may occur and slowly work your way up to larger servings over time. If you are truly terrified to introduce allergens to your baby, make an appointment with a pediatric allergist and request a prick test. These results are usually immediate and might help to put your mind at ease.

In general, there are 8 common food allergens (milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat) and one emerging (sesame). Note that many allergens on this list are also choking hazards (nuts, nut butters, shellfish, etc.), so be sure to read up on how to modify these foods to make them safe for your baby. Some tips for introducing common food allergens to babies:

  • Start small: The smaller the quantity served, the less severe an allergic reaction may be. Start with scant amounts, such as 1/8 teaspoon of a finely ground nut added to your baby’s bowl of oatmeal. If there is no reaction, try gradually increasing the amount over the next few days until you work your way up to larger amounts. Once you’ve ruled out an allergy to that food, aim to offer it to your baby as frequently as you can, but weekly at minimum.
  • Introduce allergens at breakfast: Most allergic reactions occur within two hours of consuming it (and often just minutes).6 Introducing the allergen in the morning logistically enables you to observe your child during the day ahead, and, should an allergic reaction occur, makes it easier to contact your doctor for guidance. The best time to introduce an allergen, in our opinion, is shortly after waking in the morning or right after a morning nap. For similar reasons, it is best to introduce allergens at home (and not a daycare facility or restaurant) and at a time when at least one adult can focus their full attention on the baby (without distraction from other children or household activities) for at least two hours after.
  • One at a time. When introducing food allergens to your baby for the first time, it would be wise to offer them one at a time. This way if there is a reaction, you’ll know which food was responsible. Just a few days of daily ingestion is usually enough to establish that a food is well tolerated, so you shouldn’t be afraid to offer multiple new foods each week. Pick a pace that feels comfortable and enables you to introduce a wide variety of new foods well before your baby’s first birthday.
  • Regular exposure: Once you’ve safely introduced a food allergen to your child, keep that food in regular rotation—ideally offering it to your baby on a weekly basis, at minimum. Note that not all babies with allergies will react on the first exposure so it’s important to keep serving sizes small in the beginning until you are confident there is no allergic reaction.

If I have allergies or Oral Allergy Syndrome, will I pass them on to baby in my breast milk?

Fortunately, allergies and OAS are not passed along to baby through mom’s breast milk. In general, concerns about potential food allergies should not discourage parents from offering breast milk, especially since breast milk offers a variety of nutritional and immune-supporting benefits for baby.7 Also, avoiding common food allergens in an effort to prevent food allergies either during pregnancy or when lactating hasn’t been shown to prevent food allergies and is not recommended.8

Reviewed by:

S. Bajowala, MD, FAAAAI. Board-Certified Allergist & Immunologist (allergy section)

If baby was diagnosed with CMPA, can they consume other dairy products like yogurt and cheese?

Unfortunately, no. If baby has CMPA, they can’t have milk or other dairy products, such as yogurt and cheese.9 Goat and sheep milk products are also not recommended.10 Lastly, soy milk and soy-based formulas are generally not recommended either, as CMPA can also entail sensitivities to soy and soy-based products. Remember that research shows the majority of children with cow’s milk allergy will outgrow it by age 6, and many babies with milder symptoms of milk protein allergy (which can show up as painless blood in the stool) are able to successfully reintroduce cow’s milk as early as their first birthday, with the guidance of their doctors.11

If a recipe requires milk, what is the best milk substitute for a baby with CMPA?

If a baby has CMPA, then they also need to avoid milk from other animals, soy milk, and soy-based formulas, since babies with CMPA can also be sensitive to these.12 13 Depending on the recipe, the best options for a baby with CMPA include: breast milk (from a parent who is avoiding dairy and soy in their diet), a CMPA-appropriate formula, or fortified pea protein or oat milk. When compared to cow’s milk, pea protein milk tends to be lower in calories and oat milk is usually lower in protein. For a full comparison of plant-based milks, see our Milk FAQs. Be sure to connect with your pediatric healthcare provider, such as a dietitian/nutritionist, to help identify the best substitute for your child’s individual needs.

Note: Lactose-free formula or milk are not appropriate for a child with CMPA. In CMPA, the natural proteins in milk trigger the allergic reaction, and lactose-free milk still contains these natural proteins (but is free of a natural sugar called lactose).14

Reviewed by:

V. Kalami, MNSP, RD, CSP

R. Ruiz, MD, FAAP. Board-Certified General Pediatrician & Pediatric Gastroenterologist


For more guidance, watch our video on Introducing Allergens.

Or check out our video on Introducing Peanuts, one of the most common food allergies in children.

Want to keep reading? Learn about the symptoms of an allergic reaction.

  1. FARE, Learning Early About Peanut Allergy (LEAP). [website]. (Retrieved March 3, 2020)
  2. The Journal of Allergy and Clinical Immunology, Primary Prevention of Allergic Disease Through Nutritional Interventions [website] (retrieved November 1, 2019).
  3. National Institutes of Health, Scientists identify unique subtype of eczema linked to food allergy [website] (retrieved October 31, 2019)
  4. Mayo Clinic, Food Allergy [website]. (retrieved October 31, 2019)
  5. FARE, What Is A Food Allergy? [website]. (Retrieved March 3, 2020)
  6. FARE, Common Questions. [website]. (Retrieved March 29, 2020)
  7. https://www.jaci-inpractice.org/article/S2213-2198(20)31211-3/fulltext
  8. https://www.jaci-inpractice.org/article/S2213-2198(20)31211-3/fulltext
  9. https://gikids.org/digestive-topics/cows-milk-protein-allergy/
  10. https://www.kidswithfoodallergies.org/food-allergies-and-cross-reactivity.aspx
  11. https://gikids.org/digestive-topics/cows-milk-protein-allergy/
  12. https://gikids.org/digestive-topics/cows-milk-protein-allergy/
  13. https://www.kidswithfoodallergies.org/food-allergies-and-cross-reactivity.aspx
  14. https://www.healthychildren.org/English/healthy-living/nutrition/Pages/Lactose-Intolerance-in-Children.aspx