Whey is a component of dairy products and is found in the highest concentration in non-fat dairy. It is used in the production of some cheeses, including ricotta. Dried whey is an additive in a number of processed foods, including crackers, pastries and breads. It is also used as a dietary supplement.
Whey can trigger allergies, but it is less problematic than casein protein, which is also harder to digest. Cow's milk contains about four times as much protein overall than human breast milk, with 80 percent being casein rather than whey. Whey constitutes about 60 percent of the protein in human breast milk, with casein making up only 40 percent. Baby cows naturally have an enzyme, rennet, designed to digest large amounts of casein.
Whey contains lactose and should be avoided by lactose-intolerant individuals. Dried whey contains almost 77 percent lactose. Liquid whey, as it naturally occurs in dairy products, contains protein, vitamins and minerals, and traces of fat, along with lactose. Some people are intolerant to whey itself and can sometimes consume dairy products that have had excess whey filtered out. A 2005 study found that whey may help type 2 diabetics by stimulating the release of insulin, which can help regulate blood sugar.