Allergies, Food Sensitivities and Breastfeeding

It can be helpful to know that most breastfeeding mothers can eat any and all foods while breastfeeding. Nursing parents from different cultures eat a variety of foods and children thrive on their mother’s milk.

Only about 5% of breastfeeding babies under one year of age react to a food that their mother eats. The most common food for babies to react to is cow’s milk.

Food Sensitivities and Intolerances
People sometimes confuse ‘allergies’ with ‘intolerances’ or ‘sensitivities’. Food ‘intolerances’ and ‘sensitivities’ do not cause an immune response. Although they may cause discomfort, they do not cause severe or dangerous symptoms. Fussiness and irritability during feedings may be uncomfortable, but this is not dangerous to your child.

Allergic Reactions
An allergic reaction to a food involves a sudden immune response to what the body sees as an invader. The body tries to protect itself by releasing histamine. This compound causes symptoms that can range from unpleasant to dangerous. It often affects many parts of the body. Your baby usually has to eat a food more than once before they show signs of an allergy. If they have a severe allergy, their second and future exposures can cause a more serious reaction.

Symptoms of an allergic reaction may include one or more of the following:

  • skin reactions such as eczema, rashes, hives
  • itchy mouth or throat
  • swelling of the face and tongue
  • gastrointestinal issues such as vomiting, diarrhea, bloody stools and pain
  • respiratory issues such as wheezing, coughing, and trouble breathing

The most common food allergens are peanuts, cow’s milk, shellfish, tree nuts, egg, fish, soy and wheat.

Reducing the Risk of Allergies
Exclusive breastfeeding right from birth reduces your baby’s chances of developing an allergy. This is especially important if you or your partner have a personal or family history of allergies.

The introduction of cow’s milk-based infant formula increases a baby’s risk of developing an allergy. The younger a baby is when cow’s milk protein is introduced, the more likely the baby is to develop an allergy. One 2019 study revealed that babies who are given cow’s milk-based infant formula in the first 24 hours of life are 16 times more likely to develop a cow’s milk protein allergy.

Exclusive breastfeeding and the timing of the introduction of solid foods can help prevent allergies in babies. The World Health Organization and Health Canada both recommend that:

  • babies are exclusively breastfed for the first six months.
  • family foods (solids) are introduced after six months of age.
  • breastfeeding is continued for up to two years and beyond.

Reactions to Foods You Are Eating
If your breastfed baby develops an allergy to a particular food, it is possible that your baby will react to this food in your milk. If you eat the food (allergen) and then nurse your baby, reactions usually occur within one to two hours after the feeding.

If you suspect that your baby has a reaction to a food you have eaten, you can eliminate this food from your diet. Symptoms may improve within a few days. With cow’s milk protein, it may take a few weeks to see any difference. If you eat this food again, note if your baby has the same reaction. Consider contacting a food allergy specialist for guidance.

You may want to contact a La Leche League Leader or International Board Certified Lactation Consultant (IBCLC) to rule out other breastfeeding related causes for your baby’s discomfort.

Peanut Allergy
In 2017, an expert panel produced three guidelines for introducing peanuts to babies based on different symptoms:

  • Babies with severe eczema, egg allergy, or both
    If your baby has severe eczema or egg allergy, or both, your baby may be at risk of peanut allergy. He should be tested for a peanut allergy by a healthcare provider.
    If the allergy test determines that your baby is not allergic to peanuts, the recommendation is for your baby to be introduced to peanuts between 4 and 6 months, in order to prevent a peanut allergy from developing.
  • Babies with mild to moderate eczema
    Babies who have only mild to moderate eczema should be introduced to peanuts at six months of age.
  • Babies with no eczema or any food allergy
    Babies who have no allergic symptoms or history of food allergy can be introduced to peanuts anytime after six months of age, in accordance with family preferences and cultural practices.

If you suspect that your baby may have a severe allergy to peanuts, or any other severe allergy, consult your healthcare provider.

If you have any questions about allergies and breastfeeding, contact a local La Leche League Leader for more information.

Allergies and Breastfeeding

Canadian Pediatric Society. (March 2021) Food allergy vs. food intolerance: What is the difference and can I prevent them?

Kelly, E. DunnGalvin, G., Murphy, B.P., et al. (2019). Formula supplementation remains a risk for cow’s milk allergy in breast-fed infants. Pediatric Allergy and Immunology.

Togias, A., Cooper, S.F., Acebal, M.L, et al. (2017). Addendum guidelines for the prevention of peanut allergy in the United States. Report of the National Institute of Allergy and Infectious Diseases-sponsored expert panel. Pediatric Dermatology, 34(1), e1-e21.

Health Canada. (2023, Nov 3). Breastfeeding your baby.