3 Signs Your Baby is Sensitive To Your Milk... Or Not!

3 Signs Your Baby is Sensitive To Your Milk... Or Not!

Written by Robyn Price, Prenatal and Pediatric RD and Lactation Consultant

Your baby is born with an immature gut - it is still developing and is not functioning at 100% yet. That means baby's gut is more likely to react to certain proteins if the environment is a little “off”; or a reaction can happen if your baby is programmed to respond to the environment differently (this is genetics at play!). When your baby’s gut reacts to a protein or a piece of a protein, this is commonly called a “sensitivity” or a non-IgE mediated allergic reaction.

While sensitivities can play a role in your baby’s gut function, it’s possible and in some cases even more likely, to be a feeding issue.

3 common signs that make parents THINK their baby is sensitive to something in the milk, and what might actually be going on:


With suboptimal gut function, you can get milk coming back up your baby’s gastrointestinal system rather than moving along. This can lead to pain and discomfort, which may affect your baby’s sleep and temperament. While something in the milk may contribute to suboptimal gut function, there is another possibility to rule out.

Swallowing air (aerophagia) is often caused by feeding issues, such as lip/tongue tie or poor latch. With excess air being swallowed, gas builds up causing pain and discomfort for your baby. Also the air can take up valuable stomach space leading to hiccups or burps that bring back up the milk. This is where your baby is most likely called a “happy spitter!” Combine all this with the fact that your baby’s gut is still developing and they’re on an all liquid diet, it can be tough for them to keep milk down.


Think of when you ate something that just didn’t sit well with your tummy. You may have felt uncomfortable, ill, or nauseous and you were able to communicate that to others. If something doesn’t sit well with your baby’s tummy, the only way they know how to express that is by crying. And perhaps you settle them with more milk, but that leads to more discomfort. Your baby is smart, so they refuse to eat now because that did not feel nice. You change their diaper, bathe them, cuddle them, and DO EVERYTHING, but they’re still crying. Inconsolable crying is colic and it’s not a diagnosis, but rather, a sign. A sign of something, which may very well be a sensitivity to something in your milk. But it could also be related to swallowed air (similar to what I discussed with reflux). The air can lead to a gassy baby who is very uncomfortable.


There’s nothing like the mystery of what’s in your baby’s diaper. What comes out is a reflection of what goes in, but gut function tells us what happens in between. So when you see something out of the ordinary like mucous, blood, constipation, diarrhea, green colours, or a smell that could clear a room... it makes you wonder if something is off. Since what goes in can affect gut function, it’s reasonable to think, when you see abnormal poop patterns, that it’s because of a food sensitivity. However, feeding issues may also be contributing to the problem. For example, body tension can affect your baby’s gut stimulation and contribute to infrequent poops. Or, an improper latch can cause cracked nipples and contribute to blood in your baby’s poop. The list can go on and on, and there are many possible feeding issues to be ruled out before jumping to food issues.

Although these signs all have basis for thinking your baby is sensitive to something in your milk, they also have basis for being a feeding issue. Combine that with the fact that the “something” in your milk could literally be “anything,” I often see parents embark on elimination diets for WEEKS without relief. This can lead to maternal undernutrition, mental burnout, and wasted time.

As a dietitian who specializes in breastfeeding and infant feeding, I’m able to conduct a thorough assessment, help rule out possible feeding issues, and identify whether or not an elimination diet is needed. I can then help to identify trigger foods, and create a nutrition plan without the confusion, or nutritional and mental deprivation. If you have any questions, touch base with me here! Or book online with me here. I look forward to connecting and getting you the support you need!

breastfeeding troubles gassy baby