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How to Know if Your Baby Is Lactose Intolerant


Is My Baby Lactose Intolerant?

If you have a concern that your baby may be lactose intolerant, it is probably because you have observed something about your baby or their toileting issues that has you concerned. You may suspect that your baby is lactose intolerant, but are trying to determine if they actually are.

Below, we have some more information that can help you determine if your baby truly has intolerance towards lactose.

What is Lactose?

Lactose is the sugar that is found in milk. It is present in cow’s milk as well as breastmilk. Additionally, most formulas are dairy-based and also contain lactose.

What Does it Mean to Be Lactose Intolerant?

If a person is lactose intolerant, it means that their body is unable to break the lactose down enough so that it is easy to digest. Our bodies produce lactase, a digestive enzyme, which works in our gut to break down the lactose.

If a person or baby is lactose intolerant, it means that their body isn’t able to produce enough lactase to sufficiently digest the lactose. This can lead to the person or baby experiencing uncomfortable side effects.

If your baby is lactose intolerant, it does not mean they have a milk allergy. If you suspect your baby has undiagnosed allergies, please take your baby to an allergist.

With lactose intolerance, the person’s body isn’t able to properly break down the lactose; with a milk allergy, they are allergic and react to the proteins in the milk. A milk allergy is typically more severe than a lactose intolerant.

There are three types of lactose intolerances:


This form of lactose intolerant typically doesn’t develop until later in one’s life. This type of intolerance can occur due to the body ingesting less lactose than it is typically used to. This can also occur in people or cultures that don’t eat many products containing lactose.


This is typically a temporary form of lactose intolerance. It can sometimes be caused by an infection, illness, or antibiotics that are taken for an extended period of time.


If your baby is lactose intolerant, it is likely the congenital form of intolerance. In this genetic form of the intolerance, babies are not born with sufficient amounts of lactase to break up the lactose in milk.

Some premature babies are also born with lactose intolerance due to the fact that their small intestine is not developed enough. In most of these cases, the babies outgrow their lactose intolerance with some time.

Signs That Your Baby May Be Lactose Intolerant

If you suspect that your baby may be lactose intolerant, there are various signs and symptoms you can look for to help you decide. A pediatrician can always be a great resource if you are trying to determine if your baby is lactose intolerant.

Crying Frequently

When a baby is lactose intolerant, they are often uncomfortable. Their bodies can’t break down the lactose and it is hard on their little bodies. This will often cause your baby to cry more frequently as they express their discomfort.


When the body can’t properly breakdown the lactose found in milk, it can often lead to diarrhea. If you notice a lot of diarrhea, it may be a sign that your baby is lactose intolerant.


Again, the inability for the body to properly breakdown and digest the lactose can lead to vomiting. When the body can’t properly digest something, it sometimes comes back up in the form of vomit.

Gas or Loud Bowel Sounds

If your baby is lactose intolerant, you might notice that they have a lot of gas of make loud sounds as they are pooping.

Green or Yellow Stools

In babies, lactose intolerance can frequently change the way their stools look. If you notice watery green or yellow stools, it can often mean that your baby is lactose intolerant.

Poor Weight Gain

Sometimes when a baby has a lactose intolerance they don’t gain enough weight. Since the lactose intolerance can cause vomiting and diarrhea, this can sometimes contribute to poor weight gain in a baby.

Skin Rashes or Recurring Colds

Lactose intolerance can also sometimes lead to rashes on the skin or frequent colds. So, if you have noticed either of these symptoms in your baby, it may be a sign that they are lactose intolerant.

Will My Baby Be Lactose Intolerant Forever?

It is possible that your baby may not be lactose intolerant later in their life. If your baby being born prematurely was the cause for his or her lactose intolerance, then it is possible that they may outgrow the intolerance later in life as their small intestine continues to develop.

When you talk with your pediatrician, they can share their thoughts about whether your baby may outgrow their lactose intolerance.

What Should I Do If I Suspect That My Baby is Lactose Intolerant?

If you believe that your baby has lactose intolerance, there are a few different steps you will want to immediately take to help alleviate their symptoms:

Talk to Your Pediatrician

Your first call should be to your baby’s pediatrician. They will be able to help you determine if your child does indeed have lactose intolerance.

When you go through the signs that have led to you suspect the intolerance, the pediatrician can help you determine if they point to your baby being lactose intolerant or if they may be caused by another issue that needs attention.

Change Their Diet

If your baby is lactose intolerant, you are going to need to change their diet. If they are formula-fed, there are lactose-free formulas you can switch to.

Your pediatrician can also help you select the best type or brand of formula for your baby.

If you are breastfeeding, your pediatrician may recommend using lactase drops. These drops will help your baby breakdown the lactose in your breastmilk.

Avoid Solid Foods that Contain Lactose

If your baby is already eating solid foods, or once they become old enough to begin eating solids, you’ll want to be sure to avoid feeding them foods that contain lactose. Also, be sure to check the labels on any prepackaged foods, as many foods contain ingredients with lactose.

It can be worrisome if you think your baby is lactose intolerant. But, once you use the signs and symptoms to identify the lactose intolerance, with just a few modifications, your baby can continue to grow and thrive!

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