Many people get confused about the difference between having an intolerance to casein or an allergy to milk. Sometimes, this is due to the fact that “casein” is a largely unknown term to the general public. I’ve been guilty of telling someone we simply can’t have dairy items, because it’s faster to get the point across than to educate them on the differences. However, it’s important that if you do follow a casein-free diet, that you do understand what that means and what ingredients could cause you some problems.

Let’s start with some definitions –

Casein – the proteins found in mammalian milk, the majority of it is in cow’s milk. It is a major part of cheese and can be used as a food additive.

Lactose Intolerant – the inability to digest milk and other dairy products because of the lactose (or milk sugar). Symptoms include bloating, diarrhea, and abdominal pain.

Casein Intolerant – the inability to digest casein as an ingredient in different foods; mostly dairy items. Not life-threatening, but does cause gastrointestinal distress and other symptoms like chronic runny nose, eczema, frequent ear infections, and trouble breathing.

Milk Allergy – a potentially life-threatening allergy to casein. Severity of symptoms will vary by the type of allergy: type 1 tends to manifest as skin issues like eczema, hives, or a rash; type 2 will manifest as gastrointestinal discomfort; and type 3 will usually manifest as diarrhea.

So, how do you know which one you have?

The best way to find out is by allergy testing. A milk allergy will show up on a food allergy test; the kind where they put many pokes of different substances all over your back to see what you react to the most. But, casein intolerance and lactose intolerance you will most likely discover through trial and error. If you eliminate casein from your diet, but accidentally ingest it, you may see some of the symptoms listed above and that may clarify it for you. Personally, I thought I was lactose intolerant for a long time because I didn’t know the difference between that or casein intolerance. After eliminating casein, I know now that I’m actually casein intolerant because if I even have a little non-dairy creamer in my coffee or tea, I start having a big increase in eczema and even gastrointestinal issues.

What other ingredient names actually mean “casein”?

It’s important to educate yourself on the different names that casein may use so that you can effectively avoid it. Here’s a link to a handy shopping list with all the different ingredient names that mean a product has casein in it. Remember to ask questions, particularly in restaurants, about whether an item has any dairy products in it. I was just in a brand-name coffee shop and asked about flavorings to add in for my son’s soy milk steamer and was told that all their flavorings were powdered and contained milk and whey. (Thankfully, it happened to be vanilla-flavored soy milk, so he was happy with it as is!)