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How to Understand the Difference Between Baby Food “Allergies” and “Intolerances”

Alright parents, get ready for some science! We believe knowledge is power. When you truly understand what’s causing your baby’s symptoms, it helps your family’s journey.


Having a baby with food allergies is not easy.


Parents hear time and time again that their baby has a “food intolerance” to dairy, soy, or any of the other top 12 allergies.

  • But is it really an intolerance?

  • What does “intolerance” even mean?

  • Could it be an allergy?

  • Why do medical professionals call them “food intolerances” if it’s really allergies?

Take a deep breath because we’re diving deep into this topic today — so you can feel more informed. When you know more, you can better understand what’s going on and make the best choices for your baby.


Spoiler alert: it’s very possible your baby’s “food intolerance” is truly a food allergy.


At Free to Feed, our hearts beat with the desire to support parents, just like you. Everything we do is to help you successfully care for your baby with food allergies.


Let’s get to the facts so we can help clear up this confusing topic for you!



What Do “Food Intolerance” and “Food Allergy” Actually Mean?


The easiest way to explain the difference between the two is to put it into body systems.


“Intolerance” lines up with the digestive system while “allergy” relates to the immune system.


According to the American Academy of Allergies, Asthma, and Immunology (AAAAI), infant food intolerances occur when the digestive system cannot break down certain foods from sensitivities to additives and chemicals found in food or enzyme deficiencies. [1] The food sensitivities are not due to the food proteins like in food allergies.


Key points here: digestive system and enzyme deficiency. Food intolerances occur when the digestive system is unable to break down foods. Food intolerances have nothing to do with the immune system and everything to do with the digestive system.


Infant food allergies have everything to do with the immune system.


Food allergies are defined as an immune reaction to proteins in the food (either immunoglobulin (Ig)E-mediated or non-IgE-mediated).[2] Don’t get stuck on that — the important part is the immune response. An immune response for babies with food allergies can cause symptoms in many areas of the body, particularly the GI tract.


Enzymes do a whole lot for our bodies, specifically digestive enzymes. Lacking certain enzymes can lead to improper digestion and cause issues such as lactose intolerance. [3]


When most people think of food intolerances, that’s the one that comes to mind. Using “lactose intolerance” as an example, we’ll highlight the difference between infant food “allergies” and infant food “intolerances.”


The digestive enzyme that breaks down lactose is called lactase. (We know. Did they have to make the names so similar?) So when a person or baby doesn’t have lactase, they’re unable to break down lactose, or the sugar in milk.


Lactose intolerance — the enzyme deficiency of lactase — does not cause an immune response. Because the body lacks the enzyme lactase, it can’t break down the milk sugar.


This leads to symptoms that are similar to infant food allergies like vomiting, diarrhea, bloody stools, and more.


Think of intolerances as copycats to allergies in the physical reaction. They mimic allergy symptoms. Read more on how rare lactose intolerance is in infants and what causes this condition most from our site.


Are you still with us? Hang on because this is important.


If we think about treating infant food allergies for a second, we think of removing foods from our diet to cut the allergens out, right? But — if your baby’s lacking a digestive enzyme, cutting out food allergens wouldn’t help.


If your baby has an intolerance and doesn’t produce digestive enzymes, removing food proteins doesn’t help. The root cause of the baby’s reaction goes back to the insufficient digestive enzyme — and that enzyme still isn’t there regardless! And without the proper digestive enzymes, the body can’t break down anything.


Don’t worry, we know it’s a lot to take in — but Dr. Trill is a scientist after all. Let’s carry on...


How Do Proteases, the All-Important Digestive Enzymes, Factor In?