Milk is made of two proteins, casein and whey. Whey protein can be separated from the casein in milk or formed as a by-product of cheese making.
There are three primary types of whey protein : whey protein concentrate (WPC), whey protein isolate (WPI), and whey protein hydrolysate (WPH):
Whey protein concentrate – WPC contains low levels of fat and low levels of carbohydrates (lactose). The percentage of protein in WPC depends on how concentrated it is. Lower end concentrates tend to have 30% protein and higher end up to 90%
Whey protein isolate – WPIs are further processed to remove all the fat and lactose. WPI is usually at least 90% protein
Whey protein hydrolysate – WPH is considered to be the “predigested” form of whey protein as it has already undergone partial hydrolysis – a process necessary for the body to absorb protein. WPH doesn’t require as much digestion as the other two forms of whey protein. In addition, it is commonly used in medical protein supplements and infant formulas because of it’s improved digestibility and reduced allergen potential.
Being allergic to whey means that your body doesn’t recognize the protein and your immune system thinks it is a harmful invader. Your immune system goes into attack mode, fighting off what it thinks could be harmful. While uncommon, it is possible to be allergic to milk and foods made with milk. Because whey is a byproduct of milk, it can come into contact with some of those proteins that set off your immune system.