Breastfeeding and Food Allergies

By Krista Gray, IBCLC. Last updated September 13, 2013.



What is a Food Allergy?

Food allergies occur when there is an adverse reaction to a food/substance that accompanies an immunological change in the body. The initial exposure usually does not cause an allergic reaction.  But, after the body is sensitized during the first exposure, subsequent exposures can bring a reaction.  Food allergies occur in 4-6% of children. 1 A sensitivity to cow’s milk protein is the most common allergen, ranging from 0.5-7.5%. 2

How is Breastfeeding Protective?

There has never been a documented case of a baby being allergic to his own mother’s milk. 3  In fact, the SigA in breast milk prevents most babies from developing an allergic reaction while his immature gut is still so permeable. Though babies are born with all of their organs and structures in place, many are immature and need time to grow and develop before being coated with anything other than breast milk.  Breastfeeding is protective because it allows a baby’s body to develop and mature before being exposed to nonhuman proteins and antigens as well as by slowing (in some cases preventing) the absorption of antigens in his gut that a baby does come in contact with. 4

What are the Symptoms?

There are many symptoms of a food allergy, and your baby does not need to have all of them to have an allergy.

  • Hives
  • Colic
  • Chronic Eczema
  • Gastrointestinal issues – vomiting, diarrhea, bloody stools, etc.
  • Respiratory issues
  • Fussiness
  • Poor sleep patterns 5

Top 8 Most Allergenic Foods

  • Cow’s milk protein
  • Eggs
  • Soy
  • Fish
  • Shell Fish
  • Peanuts
  • Tree nuts
  • Wheat

What if I Suspect My Baby is having an Allergic Reaction?

If your baby is displaying symptoms that suggest he has a food sensitivity or allergy it is important to look at what he is eating.  Since most babies do not have an allergic reaction to foods their mothers eat the first place to check is his intake.  Is your baby getting an occasional supplement of formula? Has he started solids?  Is there anything else he is eating/putting in his body that could be causing this reaction?  If he is exclusively breastfed, then the next step in breastfeeding and food allergies is to consider an elimination diet (see next section).

What is an Elimination Diet?

If you are breastfeeding and suspect that your baby is having an allergic response to something you have eaten you should eliminate the foods(s) you suspect as offenders.  Cow’s milk protein is the most common allergen (0.5-7.5% of babies) as beta-lactoglobulin does transfer to human milk.6  So, for example, if you suspect dairy as an offender you would want to eliminate cow’s milk in all forms – milk, butter, cheese, yogurt, ice cream, powdered milks, cream soups, etc. as well as all foods that have casein or whey as additives.  You should notice an improvement in symptoms within 2-3 days, though 2-3 weeks is necessary to remove all cow’s milk protein from your breastmilk. 7

Some mothers choose to eliminate all of the major food offenders for several weeks, then slowly add them back into their diet one by one.  Other mothers begin by eliminating the most common allergen or the one they suspect is causing the allergic response and see if that helps resolve symptoms in her baby.

If baby does improve with the Elimination Diet, how long should I continue it?

Many allergic responses that babies have to certain foods will be outgrown by childhood. Ferreira & Seidman noted in their research that most babies will outgrow an allergy to cow’s milk protein by the time they are one. 8  Whatever food(s) are problematic for your baby should never be introduced directly to your child before the age of one.  However, it is usually possible for mothers to reintroduce the offending food(s) into their diet when their babies reach 6 months.  If a reaction occurs, continue to eliminate that food.  If there is no adverse reaction a mother can begin to eat those foods again.

If you have isolated cow’s milk protein as the offender for your baby and later begin to reintroduce it to your diet, begin by introducing hard cheese, then soft cheeses and cultured dairy such as buttermilk and yogurt.  If your baby is able to tolerate these you can then try adding back butter, milk, etc.  Many moms find that after eliminating dairy entirely for a period of time they are able to reintroduce cultured dairy without any problems.  Lactose intolerance can improve as baby’s gastrointestinal tract matures.

How Should I Introduce Foods if Allergies Run in Our Family?

If food allergies run in your family, it is especially important to breastfeed your baby, and exclusively breastfeed him for the first six months.  Allergies can be hereditary: 47% of babies will have an allergy if both parents do; 29% incidence if one parent does; 13% incidence if neither parent has a family history of allergies. 9 The most effective treatment is to decrease the potential allergens and delay their introduction.  In addition to this, these guidelines can help you in deciding when and how to introduce allergenic foods to your baby.

  1. Exclusively breastfeed for at least the first six months of life.
  2. Continue breastfeeding alongside the introduction of potentially allergenic foods.
  3. Introduce foods one at a time waiting 3-5 days before introducing another.
  4. Delay the introduction of allergenic foods until after 1 year old. (Avoid hen’s eggs until 24 months and peanuts, tree nuts, fish, and seafood until 36 months.)
  5. If a supplement is required, use hydrolyzed or partially hydrolyzed formula.  Never use soy formula.

Show 9 footnotes

  1. Zieger, RS. (2000) Dietary aspects of food allergy prevention in infants and children. Journal of Pediatric Gastroenterology and Nutrition 30:S77-S86.
  2. Lawrence, RA. & Lawrence, RM. (2011). Breastfeeding: A guide for the medical profession 7th ed. Philadelphia, PA:Elsevier/Mosby.
  3. Mannel, R. et al. (2013) Core Curriculum for Lactation Consultant Practice, 3rd ed. Burlington, MA: Jones & Bartlett Learning, p.400.
  4. Mannel, R. et al. (2013) Core Curriculum for Lactation Consultant Practice, 3rd ed. Burlington, MA: Jones & Bartlett Learning, p.400.
  5. Riordan, J. & Wambach, K. (2010) Breastfeeding and Human Lactation. Sudbury, MA: Jones and Bartlett Publishers, p.655.
  6. Mannel, R. et al. (2013) Core Curriculum for Lactation Consultant Practice, 3rd ed. Burlington, MA: Jones & Bartlett Learning, p.403.
  7. Mohrbacher, N. (2010) Breastfeeding Answers Made Simple. Amarillo, TX: Hale Publishing, p.519.
  8. Ferreira, CT & Seidman, E. (2007) Food allergy: a practical update from the gastroenterological viewpoint. Journal of Pediatrics 83(1), 7-20.
  9. Mannel, R. et al. (2013) Core Curriculum for Lactation Consultant Practice, 3rd ed. Burlington, MA: Jones & Bartlett Learning, p.400.