There is actually a lot of confusion between the terms “lactose intolerance” and a “milk allergy” or “dairy allergy.” So in this post we’re going to try to clear it all up for you. First, a couple of definitions.
An intolerance to a food or group of foods is a physical reaction that does not involve the immune system. Many food intolerances stem from something missing in the digestive tract to help a person break down that particular food. Or there might be a reaction that occurs when that food is being digested that is unpleasant to the eater.
So: In order to digest lactose, the carbohydrate in cow’s milk, the body uses an enzyme called lactase. If a person does not have enough lactase to break down the lactose, they will have a reaction (like diarrhea, abdominal pain, or gas). That is lactose intolerance.
An allergy, on the other hand, is something that involves an immune system response and/or the body releasing histamines (chemicals in the body that cause allergy symptoms like runny noses, sneezing, or a rash). When a person has an allergy to something, their body has an immune response and releases chemicals to “fight” that thing.
So: People who are allergic to milk are most likely allergic to one or more of the proteins found in milk. When their bodies try to digest these proteins their immune systems respond to the protein by trying to fight it off. Symptoms can range from the abdominal issues that might be felt with lactose intolerance to much more severe reactions like hives, a rash, vomiting, wheezing, and even anaphylactic shock.
Milk allergies are most common in early childhood (2 to 3% of infants) but for most kids the milk allergy goes away by age 3. It’s a pretty rare condition among adults.
The good news is that if you’re over age 3 and having gastrointestinal symptoms, you’re probably dealing with an intolerance and not an allergy. What’s even better is that a lot of people with lactose intolerance are able to drink Hansen’s milk because it’s less processed than most milk and non-homogenized.