Finding out that your baby is allergic to something in your breast milk is incredibly stressful and difficult. Having to eliminate yummy foods from your diet to try to figure out which food is the culprit and thinking something you are ingesting could be causing your little one discomfort is just awful. Its especially frustrating when you know you are doing the very BEST thing for your baby by breastfeeding, yet, you see your LO squirming in pain.


We as mamas want to do everything we can to make our babies thrive and feel comfortable. The good news is that once you’ve figured out that it’s food that’s causing all these issues, it can be an enormous relief, you can make changes to fix it, and it can help you feel empowered as a mama again.

Please keep in mind that this topic is deep and complex, with allergies often being misdiagnosed because symptoms are varied. A fussy baby can be mistaken for having a food allergy because everyone needs an answer to why the baby wont stop crying. The truth is, its super unlikely that something you are eating is the culprit. “In fact, only two or three out of every one hundred babies who are exclusively breastfed demonstrate an allergic reaction—and that’s most often to the cow’s milk in their mother’s diet.”

However, if your child IS diagnosed, here’s what you need to know about allergies and breastfeeding:

1. Allergies occur when your body perceives a potentially harmless substance as an invader. A newborn who has never had anything but his mother’s breast milk can still show signs of allergy because of the foods you are eating.

2. Common signs and symptoms of an allergy include:

  • Eczema (or other skin reactions like a rash or cradle cap or hives)
  • Stools that are loose, watery, green*, more frequent, or contain blood.
  • Cramping, constipation, bloating, gas, heartburn, reflux, vomiting.
  • Nasal congestion
  • Persistent ear infections
  • Dark circles under the eyes
  • Slow or stalled weight gain (from malabsorption of nutrients)
  • Excessive crying
  • Frequent interruption of sleep
  • Fussy, “colic-y”, and miserable little babe

*Please note: green-mucousy poops can also been seen from over-supply, from too much lactose from foremilk. The signs/symptoms listed above will be consistent, dramatic, and in combination.

3. There has never been a documented case of a baby being allergic to his own mother’s milk. What the baby is actually allergic to is a protein that passes through her milk from the food she ingests.

4. Allergies typically show up at around 6 weeks of the baby’s life

5. Magical antibodies are found in your breastmilk: Secretory IgA is produced in very large amounts in your colostrum. This antibody binds with and prevents transport of dietary allergens until the infant gut is less permeable and they start producing SigA on their own.

6. If you are concerned about a possible allergy being the culprit of your fussy kiddo, start by reaching out to your pediatrician, an International Board Certified Lactation Consultant and an allergist. These professionals can help guide you. You should also check in with an a nutritionist if you have to remove a major food/food group from your diet for replacement of the nutrients.

7. Top food allergens:

  • Dairy (cows milk protein)
  • Egg
  • Soy
  • Wheat
  • Peanuts
  • Tree nuts
  • Fish and shellfish

Although these are the top foods to watch out for, with a child with food sensitivities, the list can seem like it’s endless. And I hate to say it but coffee and chocolate in large amounts can cause irritability and wakefulness in your little one. (eek!)

Processed and genetically modified foods can also cause reactions so avoiding these will make you feel better and help your little one.

Any food may cause an allergic reaction (which is why this is so tricky) but 90% of them in children are caused by the food groups listed above (minus the fish and shellfish, which is more common for adults).

8. Some infants are so vulnerable to an allergy, you may see symptoms when they just come in contact with the food, and/or immediately after you ingest the food. However, a reaction usually occurs within 4-24 hours, and the food you ingest is in your babe’s system within 4-6 hours.

9. Dairy is the most common allergen. Melinda Wenner Moyer writes that “Somewhere between 2-8% are allergic to cows’ milk, but among babies who have only ever been fed breast milk, the risk is only about 0.5%.”

Even if you are not allergic to dairy yourself, your baby may be. If you eliminate dairy from your diet, you should see improvement within days and up to 2 weeks. However, it can take up to 6 weeks for dairy to be completely out of your system. Make sure you look at all labels—watch for casein and whey.

Breastfed babies who are sensitive to dairy in your diet are reacting to the cows’ milk antibodies in the form of proteins, NOT to lactose. (So what this means is your baby is not lactose intolerant. Trying lactose-free dairy products will not help your babe.)

10. What you may think is an allergy may actually only be a reaction, intolerance, or sensitivity to a food. A true allergy will most likely hang around for life, but a reaction or sensitivity can be outgrown as the digestive system matures—typically by 3 years old.

11. Allergic disease has a strong hereditary basis. If you are in a high-risk allergic family, or have a strong family history of allergies, you may want to avoid potent allergens (like peanuts or dairy products) during pregnancy and breastfeeding.

12. Unfortunately, allergy testing in young infants is not considered reliable and can give false negative results so the best way to figure out what is causing your baby problems is through an elimination diet. If you eliminate one allergen at a time, you should wait a minimum of two weeks and up to four weeks.

Elimination diets: 3 ways to do them (with the guidance of your doctor)

  1. You can try eliminating one allergen/food group at a time
  2. Try a low allergen diet
  3. Try a total elimination diet from the beginning

When you do an elimination diet, make sure you:

  • Keep a journal of all the foods you eat and your baby’s reaction/symptoms
  • Space the re-introduction of any food out by 4-5 days

You should see improvement within 2-7 days and up to three or even four weeks as the newborn’s intestines and stomach lining become less inflamed and irritated.

Total elimination diet

  • Step 1: When you begin, you need to cut back all the way to the bare bones: fruits and veggies (and nothing too acidic, so no citrus!). You should see improvement in a few days in your babes poop: No more diarrhea? No more blood? Green poop no longer green? Eczema will take more time to clear up but does it look less inflamed?
  • Step 2: Introduce beans, one kind at a time.
  • Step 3: Introduce grain. Try rice first.
  • Step 4: Once you have eliminated all possible allergens, you can try your food challenge by introducing one of these types of foods at a time. Go slowly, wait sufficient time, and know that some babies are fine with small amounts of the allergen but will not tolerate it anymore when it reaches a certain level.

You may opt-out of doing a food challenge altogether if by eliminating possible allergens, you now have a happy and comfortable baby. The re-introduction can seem really scary and daunting. You may want to try waiting a year (when many food sensitivities are outgrown) before reintroducing the foods back in your diet.

13. Rotation diet

This will allow you to eat troublesome foods in a rotating schedule, so each food is out of your system for 5-7 days before you reintroduce it. This can prevent allergic symptoms to develop. This kind of diet can help identify the culprit without disrupting your own diet too much, although some believe the foods are not eliminated for a long enough time.

Most importantly: Please try not to blame yourself for this, mama. Talk to your doctor, IBCLC, allergist and nutritionist about what would be best for you and your babe. It is normal for our babies to cry and you may just be the ‘lucky’ one who has an intense, needy and sensitive baby who cries a lot. However, if there is a true allergy or sensitivity, you do not need to wean your baby from the breast. If you change your diet, you and your baby can continue to enjoy breastfeeding for as long as mutually desired.

Be patient, be gentle on yourself, and take it one day at a time.