Milk Allergy vs Lactose Intolerance
Updated: Oct 13
What’s the difference? They are both allergies to dairy, right?
Well, not exactly. One is an allergy. The other is an intolerance. What does that mean?
An allergy is an immune-mediated reaction, meaning that our immune system (our body’s defense system) is involved. In milk allergy, the person’s body has an abnormal response to one (or both) of the proteins found in dairy - casein and whey.
When the immune system is involved, this can lead to a severe allergic reaction which can include life-threatening symptoms. This is referred to as anaphylaxis.
Some symptoms of anaphylaxis may include trouble breathing, a drop in blood pressure and hives. This can lead to shock - a situation where your organs do not receive enough oxygen to function. A dairy allergy is very dangerous, and can develop at any age. All types of dairy that contain either protein, casein or whey (butter, milk, yogurt, cheese, etc.) must be avoided completely.
On the other hand, an intolerance is not mediated by the immune system like an allergy is. Lactose intolerance is specifically an enzymatic intolerance.
A person with lactose intolerance is not able to break down the sugar known as lactose. This is a key difference - in allergy, the person has a reaction to the proteins found in dairy, while in lactose intolerance, the person has a reaction to the sugar found in dairy.
Lactose (the sugar) is broken down in our small intestine by an enzyme called lactase (this is why lactose intolerance is specifically an enzymatic intolerance). When the enzyme lactase is not properly produced, the body cannot break down lactose, and this causes gastrointestinal symptoms.
Although these symptoms may be every uncomfortable, they are not life-threatening.
So next time someone says they're allergic to dairy, be sure to ask if they mean a true allergy or an intolerance!
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