Whey protein comes from cow's milk and can be separated from milk during the process of making cheese. Whey protein isolate is a more purified version of whey protein, which contains more protein by weight, with almost no carbohydrates or fats. Whey protein isolates are commonly used in whey protein blends.
Whey protein is made by drying the material left behind after the liquid portion of milk is filtered. This product is commonly referred to as whey protein concentrate. Whey protein concentrate can contain between 30 and 80 percent protein by weight. Whey protein concentrate contains all of whey protein's biologic components.
Whey protein isolate is formed by further processing whey protein concentrate, using techniques known as ion exchange or crossflow microfiltration. The level of fats and carbohydrates in pure whey protein isolate is virtually nonexistent. In addition, whey protein isolate usually contains no lactose, or milk sugar. Being such a pure form of protein makes whey protein attractive to some individuals who are interested in weight loss or muscle building. However, Dr. Charlie Seltzer notes on the Built Lean website that whey protein isolate is so purified that it causes the loss of certain peptides, which means it may theoretically be at a disadvantage, health-wise, compared to whey concentrate, which contains these components.
Advantages and Disadvatages
Whey protein isolates are absorbed by the body more quickly than concentrates, which may make them a superior choice for post workout supplementation. However, Seltzer also notes that because whey protein isolate may also affect insulin levels more, those who want to watch their insulin rises may want to avoid whey isolate. Whey protein isolate also costs more than whey concentrate, because of the extra processing it must undergo.
Whey Blends & Comparisons
A blended version of whey protein contains both whey concentrate and whey isolate. This is one of the most common versions of whey protein powder because of its cost advantage over whey isolate and its purity advantage over whey concentrate. One popular brand of a whey protein blend contains 24 grams of protein per 31.5 gram scoop, making it 76 percent protein, by weight. One popular brand of whey protein concentrate contains 20 grams of protein per 40 grams scoop, making it 50 percent protein, by weight. One brand of pure whey protein isolate powders contains almost 90 percent protein by weight.