Dairy Intolerance in Breastfed Babies (What You Can Do About It)

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Do you suspect your breastfed baby is sensitive to dairy in your diet? Here is what you need to know about dairy intolerance in breastfed babies, and what you should do about it.

Dairy intolerance is a commonly recognized problem in the first year of life for a lot of babies. Researchers have concluded that upwards of 15% of infants experience symptoms that suggest dairy sensitivity (source)! But for something that happens so often, you don’t actually hear it talked about much.

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Unsure of how to start a dairy-free breastfeeding diet? Our FREE guide will give you 5 tips to help you get started. You don’t always have to switch to formula!

Dairy issues—much like tongue ties—fall on a spectrum. For some babies, it’s super obvious that dairy doesn’t agree with baby. These babies might have trouble breathing, break out in bad rashes, and cry inconsolably. On the other end of the spectrum are babies like mine:

By all accounts, my oldest baby was a pretty happy baby. She wasn’t a chronically fussy kid. She slept okay. Like most infants, she had a little bit of reflux, but it really didn’t seem to bother her and no one was worried about it. She stooled frequently, and her poop was pretty mucousy, but it had always been like that. She had these tiny patches of dry skin that didn’t respond to lotion, but they didn’t itch or bother her. On occasion, she would break out in what appeared to be hives. Most of the time her skin was normal though, so her pediatrician didn’t think anything of it. 

But one day, when she was 6 months old, I noticed a tiny—but bright red—streak of blood in her diaper. 

Dairy Intolerance in breastfed babies and what you should do about it

We turned to a new pediatrician, who tested my daughter’s allegedly “normal” mucuosy stool for invisible, microscopic blood, and it came back positive. 

My baby was most likely reacting to diary, the new doctor said, but I didn’t get a clear answer about what that actually meant going forward. Was she allergic to my milk? Should I eliminate dairy from my diet to keep breastfeeding? Is that hard? Could it be risky? Is it worth it? And how quickly would I see results if I tried?

If you’re a breastfeeding parent who is in a similar place right now, I have some answers for you. But first, let’s start from the beginning:

Medical Disclaimer: The content of this blog post is not medical advice nor is it a substitute for medical advice, diagnosis, treatment, or professional lactation care. This post is for educational and informational purposes only. It is the reader’s responsibility to review all information regarding any medical condition or treatment with a healthcare provider.


Technically “dairy sensitivity” (a.k.a. “dairy intolerance”) is not quite the same as a true dairy allergy, and it’s also different from lactose intolerance (source, source). But to make things really confusing, the internet—and even doctors—often throw the terms around interchangeably. But they’re not all the same thing!

True dairy allergies (IgE mediated dairy allergies) cause an immune system response that is usually pretty immediate, can affect multiple body organs, and can be anywhere from mild to life-threatening. For example, a baby with a dairy allergy might break out in hives (usually on the face, chest or belly), have difficulty breathing, or experience swelling (often in the throat or tongue) when coming in contact with dairy. Babies with true dairy allergies might also have digestive symptoms such as reflux or vomiting, painful gas, and diarrhea. Upwards of 7.5% of infants are allergic to dairy (source).

Baby with dairy rash on his cheeks
Some babies sensitive to dairy will have visible rashes or eczema.

A dairy protein sensitivity/intolerance (non-IgE mediated reactions to dairy), on the other hand, usually causes reactions that are primarily (but not exclusively) digestive in nature. For example, a baby that is sensitive to dairy proteins might have gas, reflux, and green, mucousy stool that may or may not be visibly bloody. Stool might be loose or baby may be constipated. Eczema and congestion are also common. Symptoms of dairy sensitivity/intolerance can crop up hours or days after exposure and can sometimes be mild enough that a person doesn’t realize what they are experiencing is a reaction to dairy proteins. 

To complicate things further, dairy intolerance/sensitivity is different from lactose intolerance (source, source). A lactose intolerant child does not produce lactase, the enzyme needed to break down lactose, a sugar in milk (all mammalian milk—human and cow). On the other hand, a child with a dairy sensitivity/intolerance can produce lactase but has difficulty digesting the proteins in cow’s milk (and all products made from cow’s milk, like butter, cheese, cream, etc.) like whey and casein. 

Mucous in the stool of a dairy-intolerant baby
This dairy-sensitive baby’s stool tested positive for invisible (microscopic) blood. Sometimes babies will have mucous in the stool for reasons other than dairy intolerance.

Lactose intolerance is super extremely rare in infants. When a baby truly can’t have lactose, they usually have a very rare hereditary carbohydrate metabolism disorder called galactosemia. This condition is screened for via blood test at birth (I don’t recommend skipping those blood tests!). Otherwise, lactose intolerance doesn’t typically develop until childhood or even adulthood. 


Since true IgE mediated dairy allergies typically produce strong and immediate reactions, they can be easier to diagnose in babies. But when it comes to dairy protein sensitivity/intolerance, blood tests and scratch tests are unreliable and notorious for producing false positives (indicating an allergy or sensitivity when there is none) in babies. If a dairy protein sensitivity/intolerance (non-IgE mediated) is suspected, blood and scratch tests aren’t necessary (sourcesource

To complicate matters even more, the body can develop sensitivities over time, and some children experience both IgE- and non-IgE mediated reactions to dairy (source). 

This baby spent the first several months of her life consuming dairy proteins through breastmilk before her reactions to dairy started to become more noticeable.
This baby spent the first several months of her life consuming dairy proteins through breastmilk before her reactions to dairy started to become more noticeable. Left: How her skin normally looked, Right: Her skin during a reaction.

An allergist can help rule out a true dairy allergy, perhaps with a skin prick test or a blood test. But the most reliable way to test for dairy protein sensitivity/intolerance in infants is to eliminate the offending food and see if symptoms improve. 


As a breastfeeding parent, here’s what you should be sure to do if you suspect your baby is reacting to dairy:

1) Speak with your pediatrician

It’s important to keep your child’s doctor appraised of all symptoms. 

But it’s also important to keep in mind that many pediatricians aren’t allergy specialists or experts in the diagnosis and management of dairy issues in breastfeeding infants (source). Parents who wish to continue breastfeeding their dairy-sensitive babies are often told they must temporarily switch to hypoallergenic formula while they eliminate dairy from their diets. However, according to the Academy of Breastfeeding Medicine (a panel of MDs who are also breastfeeding experts), temporarily switching to formula while you eliminate dairy is usually not necessary (source). 

Most breastfeeding parents can continue to breastfeed while eliminating dairy from their diets. 

Bring questions and concerns about cows milk allergy or intolerance to your baby's healthcare provider
It is important to meet with your baby’s healthcare provider if you suspect your baby has a dairy issue.

2) Consider meeting with an IBCLC to rule out other issues.

Dairy sensitivity/intolerance symptoms—such as frequent spitting up, painful gas, and colic—often overlap with symptoms of tongue ties, oversupply, and reflux. So it is important to rule these things out. An IBCLC (international board certified lactation consultant) is uniquely qualified to help you determine if other breastfeeding issues (e.g. poor latch, fast letdown, oversupply, tongue/lip ties etc.) are contributing to your baby’s symptoms and can help you get these breastfeeding issues under control. 

Many IBCLCs (lactation consultants) offer telehealth appointments
Although an in-person appointment is ideal, many lactation consultants (IBCLCs) offer telehealth appointments if needed.

3) Consider eliminating dairy from your diet.

While it is tempting to jump into an elimination diet, I don’t usually recommend it right away. This is because elimination diets tend to require a bit of time and dedication, and it’s good to be pretty confident you’re dealing with a dairy issue before making such a commitment. It is easy to mistake normal infant reflux or other normal (but frustrating) baby behaviors as signs of a dairy issue.

The truth is, eliminating dairy isn’t as simple as avoiding cow’s milk! Remember that dairy proteins are in cow’s milk and everything derived from cow’s milk. So cheese, yogurt, butter, many protein powders, ice cream, etc. Cow’s milk proteins go by a lot of strange names (e.g. sodium caseinate, ghee, lactate solids, etc.) that can be hidden deep in ingredients lists. If your baby is quite sensitive, you’ll need to look for these things and avoid foods containing them. Unfortunately, dairy is in a lot of processed food, packaged food, fast food, and restaurant dishes.

Can you spot the hidden dairy in this photo of a hamburger and fries?
Can you spot the hidden dairy in this photo? There may be dairy on/in the toasted bun, in the condiments, or in the french fries.

Furthermore, some babies experience what is known as “cross-reactivity.” In other words, sometimes the body reacts to proteins that aren’t cow’s milk proteins but look a lot like them. This is why many dairy-sensitive babies cannot have goat’s milk or goat’s milk products, and why a surprisingly large percentage of dairy-sensitive babies are also sensitive to soy. 

It can take about 4-6 weeks for dairy to totally leave your and your baby’s systems. However, many people with dairy-sensitive babies usually notice an improvement in symptoms in as little as a few days. But if you don’t notice a big difference right away, don’t despair! It can take longer than this to see results, so consider giving your elimination diet more time: at least a couple of weeks if not the full 4-6. 

Mother cooking at home following a dairy-free breastfeeding diet
Eating dairy-free helped me personally get better at meal planning which helped me lose 68 pounds after having my baby!

While I know this sounds daunting, don’t be afraid! Starting a dairy-free breastfeeding diet IS DOABLE and many breastfeeding parents do it very successfully. Many babies wind up eventually outgrowing dairy sensitivities, so depending on how long you choose to breastfeed, you won’t necessarily need to eat dairy-free the entire time.

how to breastfeed dairy-free when you should do it and tips to get started
Nurturing Milk’s sister blog, Mom Makes Joy, has this helpful post, which includes more info on how to start a dairy-free breastfeeding diet!

4) Get tips and support.

I strongly encourage you to join a support group for breastfeeding parents where you can ask questions and meet people who might have experience with this issue! I co-run this (inclusive) lactation support group with two other experienced and knowledgable ladies, and we’d love to have you.

And don’t forget to grab this free printable cheat sheet for starting a dairy-free breastfeeding diet:

Start Breastfeeding Dairy Free Today!

Unsure of how to start a dairy-free breastfeeding diet? Our FREE guide will give you 5 tips to help you get started. You don’t always have to switch to formula!

And of course, if going dairy-free isn’t going to work for you, remember that hypoallergenic infant formulas are also an option!

Before selecting a formula, speak with your pediatrician. Some recommended hypoallergenic formulas are still fundamentally dairy-based, so very sensitive babies may still react to them. Amino-acid based formulas, although very expensive, may or may not be recommended by your child’s doctor. Keep in mind that very sensitive babies may still react to soy formula, and and goat’s milk formulas are not recommended for babies with dairy issues.

Whatever you choose, make sure your decision is made in consult with your child’s pediatrician. And if your child’s doctor is not supportive of you continuing to breastfeed, it may be worth it to seek a second opinion.


If you enjoyed this post–and if you’re feeling a bit overwhelmed by the prospect of starting a dairy-free breastfeeding diet–be sure to check out my complete digital mini-library of helpful dairy-free breastfeeding resources:

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