Whey

Whey or milk plasma is the liquid remaining after milk has been curdled and strained; it is a by-product of the manufacture of cheese or casein and has several commercial uses. Whey is used to produce ricotta and gjetost cheeses and many other products for human consumption. It is used as an additive in many processed foods, including breads, crackers and commercial pastry. In addition, whey is used as an animal feed. Whey proteins mainly consist of α-lactalbumin and β-lactoglobulin. Depending on the method of manufacture, it may also contain glycomacropeptides (GMP).

The whey protein separated from this mixture is often sold as a nutritional supplement. In addition, liquid whey contains lactose, vitamins, and minerals along with traces of fat. Researchers at Lund University in Sweden discovered that whey appears to stimulate insulin release. Writing in the American Journal of Clinical Nutrition they also discovered that whey supplements can help regulate and reduce spikes in blood sugar levels among people with type 2 diabetes by increasing Insulin secretion.

Dietary concerns
The most commonly used milk curdling agent is the animal-derived rennet. Vegetarians may use vegetable-source rennet or lemon juice, citric acid or sulfuric acid to separate milk into curds and whey.

People who are allergic to dairy proteins should avoid consuming whey. Individuals who are severely intolerant to lactose may need to select a bioactive 90% whey protein (lactose-free), such as AIS MAX, Immunocal or Imuplus. Additionally, whey protein isolates are low in lactose and may be appropriate for mildly lactose intolerant persons.

As a supplement, whey concentrate served the purpose of providing a high source of protein for post workout recuperation. However, individuals suffering from lactose intolerance were unable to ingest whey concentrate. As a result, whey isolate was marketed as a lactose free alternative providing a higher concentration of protein per mass unit and lowering the carbohydrate content of the supplement.