Whey protein is commonly marketed and ingested as a dietary supplement, and various health claims have been attributed to it in the alternative medicine community. Although whey proteins are responsible for some milk allergies, the major allergens in milk are the caseins.
ProductionWhey is left over when milk coagulates and contains everything that is soluble from milk. Processing can be by simple drying, or the protein content can be increased by removing lipids and other non-protein materials. For example, spray drying after membrane filtration separates the proteins from whey.
CompositionWhey protein is the collection of globular proteins isolated from whey, a by-product of cheese manufactured from cow's milk. Cow's milk is 20% whey protein and 80% casein protein, whereas human milk is 60% whey and 40% casein. Whey protein is typically a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), and serum albumin (~8%), which are soluble in their native forms, independent of pH. The protein fraction in whey (approximately 10% of the total dry solids within whey) comprises four major protein fractions and six minor protein fractions. The major protein fractions in whey are beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin and immunoglobulins.
Major Market FormsWhey protein typically comes in three major forms:
- Concentrates contain a low level of fat and cholesterol but, in general, have higher levels of bioactive compounds, and carbohydrates in the form of lactose — they are 29%–89% protein by weight.
- Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Both of these types are mild to slightly milky in taste.
- Hydrolysates are predigested, partially hydrolyzed whey proteins that, as a consequence, are more easily absorbed, but their cost is generally higher.Highly-hydrolysed whey may be less allergenic than other forms of whey. They are very bitter in taste.
Whey protein contains the amino acid cysteine which can be used to make glutathione. However, this amino acid is not essential for the synthesis of glutathione and some studies have suggested that the amount of cysteine in the diet may have little effect on glutathione synthesis. However, another study suggested that large amounts of whey protein can increase cellular glutathione levels. Glutathione is an antioxidant that defends the body against free radical damage and some toxins, and studies in animals have suggested that milk proteins might reduce the risk of cancer.
Commercial whey protein products are extremely refined (generally not a good thing) and expensive foods! Though a growing body of legitimate clinical research is show measurable HEALTH benefits little if any research shows sports specific benefits in athletes already consuming 1.5g/kg or more of dietary protein.
As a strength athlete I would focus more on whole food sources of protein and save whey for the children and geriatric patients who could gain some immunological benefit.