Is milk allergy and lactose intolerance the same

Difficulty digesting dairy can be attributed to two common culprits: lactose intolerance and milk protein allergy. But is there a difference?… Yes! Individuals suffering from lactose intolerance do not manufacture an enzyme called lactase, whereas a milk protein allergy is an abnormal immune system response to cow’s milk. The differences in dietary guidance for each of these groups comes down to safety. Let’s dig a little deeper.

Lactose intolerance effects quite a large portion of the global population, prevalent in 70 to 100% of east Asian populations, as well as those of West African, Jewish, Greek, and Italian descent.1 However it effects some more than others, as lactose intolerance only effects ~5% of people from Northern European descent.1

What does this mean? It means that in the diverse world in which we live, it’s likely you know someone that cannot process lactose, it may even be yourself. 

Unlike milk protein allergy, in which the allergen is the protein component, lactose is a sugar (or the carbohydrate component) found in milk and other dairy products. When our bodies do not manufacture an enzyme called lactase, we cannot digest lactose and this causes symptoms such as abdominal pain, bloating, gas, nausea, and diarrhea.1 Think of lactase as a key that unlocks lactose, so we can break it down and use it for energy. This is how typical digestion should work, but for individuals suffering from lactose intolerance, this enzyme is missing.

There are varying degrees of lactose intolerance, and some people can tolerate small amounts of lactose in their diet. There is naturally less lactose in yogurt and cheese due to fermentation and processing, so these foods can potentially fit into a diet notwithstanding lactose intolerance (however this can be individualized), and management can be achieved by diet alterations or over-the-counter lactase supplementation.2

On the label, if a product has dry milk solids, lactose, or lactose monohydrate as an ingredient, it may cause trouble.3 Products labeled as lactose-free are generally safe.3 However, milk proteins may still be left behind. 

A milk protein allergy is an abnormal immune system response to cow’s milk. While affecting 2-6% of children4, unlike lactose intolerance which differs by ethnicity, milk protein allergy is less common in adults. The main proteins in cow’s milk are called casein and whey, and symptoms can include blood-streaked stool, wheezing, coughing, and vomiting to name a few.4,5 It is imperative with this diagnosis to avoid milk proteins to prevent immediate, sometimes severe illness, and possible long-term effects (such as failure to thrive in infants and kids). Foods that contain milk proteins are6:

• Milk/buttermilk 
• Cream 
• Butter/margarine
• Whey
• Casein
• Cheese
• Yogurt
• Sour cream 

Check the ingredients list on your favorite items for these milk protein allergens. 

*Pro-tip: A plant-based or vegan label does not automatically mean it is safe! The ingredients list still must be checked for casein and/or whey as milk proteins can be engineered and added*  

By Mollie Johnson, RDN 

If you have more questions about the difference between lactose intolerance versus milk allergy, it’s always a great idea to speak with a registered dietitian. Registered dietitians are the only credentialed experts qualified to address your unique health questions. Email us at [email protected] to request a direct consultation with a dietitian today!

Both a lactose sensitivity and a cow's milk allergy can cause tummy troubles in infants, but how do you tell them apart? Read on.

Q: What Is The Difference Between Cow's Milk Allergy And Lactose Intolerance?

JK: Lactose intolerance and cow's milk allergy may have similar symptoms — you might see nausea, vomiting, stomach cramps or diarrhea. It can be tricky to distinguish between the two but they're actually completely different conditions.

• A food allergy, such as cow's milk allergy, is an immune reaction to the protein in milk.
• A lactose intolerance is caused by the inability to break down lactose, which is the sugar in milk.

Lactose sensitivity can be uncomfortable for your baby, but it's otherwise harmless.

A food allergy, on the other hand, can be very dangerous and might also cause additional symptoms. There could be some mild reactions like flushing, rash, hives or a runny nose. Others can be much more serious, like trouble breathing, wheezing, swelling of the tongue and throat and even loss of consciousness. To stay safe, milk-allergic infants need to completely avoid all foods with milk-containing ingredients.

Q: What Should Parents Do If They Suspect Their Baby Is Milk Allergic Or Lactose Intolerant?

JK: When a baby has trouble tolerating formula, many parents automatically assume that it's because of a milk allergy. Don't try to diagnose the symptoms. The very best thing you can do is speak to your child's doctor. They'll be able to do a thorough exam, take a full history of any symptoms and order additional tests or refer you to a pediatric allergist.

Related: Download My Child's Symptom Diary Log

Q: Do Babies Who Have Lactose Intolerance Or Cow's Milk Allergy Need To Have A Dairy-Free Diet?

JK: If your baby is diagnosed with a cow's milk allergy, they will need to avoid all milk products completely, but lactose intolerance is a little different.

Infants are rarely diagnosed with lactose intolerance. However, it's not uncommon for babies to experience lactose sensitivity due to diarrhea from a virus or antibiotic use. The good news is this type of secondary lactose intolerance usually goes away on its own shortly after the illness resolves. Because it's almost always short term, there's typically no need to change your baby's diet, but while your little one is experiencing symptoms they might be more comfortable with a reduced lactose formula such as Similac Pro Sensitive or Similac Total Comfort.

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