Whey is one of the two main proteins found in cow’s milk. The other is casein. When milk is separated during the cheese making process, the liquid portion that remains is whey. It is commonly used in protein powders, baked goods, snack foods, and many processed products.
For someone with a milk allergy, whey can trigger an immune reaction. This is very different from lactose intolerance. Whey is a milk protein, which means it can cause symptoms like hives, swelling, vomiting, coughing, wheezing, or even anaphylaxis in someone who is allergic.
Whey can appear on ingredient labels under names like whey protein concentrate, whey protein isolate, or simply whey. If a product contains whey, it contains milk.
Because whey is often added to foods for extra protein or texture, it can show up in places you might not expect. That is why careful label reading is so important for families managing a milk allergy.
If you are unsure whether someone is reacting to whey, casein, or both, you can visit with a board certified allergist.
