Can a Baby be Allergic to Breast Milk?

The first thing to understand is that breast milk is a mixture of water, fats, sugar, nutrients, bacteria, amino acids, and pre-processed protein a baby’s growing body needs.

The second thing to understand is that breast milk is water and nutrients pulled from a mother’s circulatory system (blood stream), not her stomach. And a mother’s blood stream only has nutrients / vitamins / proteins that have already been broken down by the mother’s body. 

Babies cannot be allergic to breast milk, but they can be allergic to unprocessed proteins that make it into the breast milk. 

However, is it not that common for this to happen, and here’s why. 

For a baby to react to unprocessed protein in breast milk:

1. Mom has to have poorly processed proteins in her bloodstream
2. Mom has to pass those unprocessed proteins into her milk
3. Baby has to have a gut barrier that reacts to those unprocessed proteins

Again, while not super common, it is totally possible. 

Allergies to proteins in breast milk will look different than food allergies you may see in older children. The most common symptoms are mucus or bloody stools, stomach pain, eczema or rashes, or colic. Of course, lots of other things can cause those issues. 

How to Fix Allergies to Breast milk

If your baby seems to be reacting to something in your breast milk, a guided elimination diet of top culprits (dairy, nuts, eggs, soy, corn, oats, wheat), followed by a slow re-introduction can help find the cause. Once you know the cause, avoiding that food for about 6 months is recommended. 

Another option is to strengthen the baby's gut barrier with probiotic supplements that include allergy-preventing strains, and supplements that improve mom’s gut barrier to reduce proteins in her breast milk.