US Pharm. 2009;34(9):HS-14-HS-18.
Protein is an important macronutrient needed by everyone on a daily basis. It repairs body cells, builds and repairs muscles and bones, controls many of the important processes in the body related to metabolism, and provides a source of energy.1
Whey protein is a high-quality protein from cow's milk, containing all of the essential amino acids. Milk is composed of two forms of protein: casein protein (80%) and whey protein (20%). Whey protein is more soluble than casein protein and is of a higher quality. It is often referred to as the most nutritious protein available. Whey contains less than 0.5 g of fat and only 5 mg of cholesterol per serving. Pure whey protein does not contain any gluten.2
Whey protein is also the best source of branched chain amino acids (BCAAs [leucine, isoleucine, and valine]). The body requires higher amounts of BCAAs during and following exercise. Unlike other amino acids that must first be metabolized through the liver, BCAAs are taken up directly by the skeletal muscle. Low levels of BCAA contribute to fatigue, and they should be replaced quickly following exercise or a competitive event. Whey protein is compatible with low-carbohydrate diets and is an ideal choice for athletes.2
Individuals who combine leucine-rich diets with exercise have more lean muscle tissue and lose more body fat. As they lose fat, their metabolic rate increases and they naturally burn more calories each day. Whey protein also helps manage weight by promoting satiety, or a feeling of fullness. Whey protein is superior to casein protein in promoting satiety. Whey protein provides high-quality protein without carbohydrates and fat, but is often limited in low-carbohydrate diets. In this review, we briefly discuss the production, different forms, health benefits, and other advantages of whey protein.
During the process of making cheese, when milk coagulates the soluble left over is whey. It contains about 5% lactose in water, with certain minerals, lactalbumin, and some fat. A technique of spray drying and membrane filtration separates the whey protein from the fat (TABLE 1). Whey protein can then be used in several different ways in cooking and is very digestible. The price of whey is 25% to 40% less than that of other dairy products.
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 (65%), alpha-lactalbumin (25%), bovine serum albumin (8%), and immunoglobulins (2%). Each of these components has important disease-fighting effects.3,4
Whey protein typically comes in three major forms: concentrate, isolate, and hydrolysate.4
Concentrates contain a low level of fat and cholesterol. Whey protein concentrate has anywhere between 29% and 89% protein depending upon the product. As the protein level in whey protein concentrate decreases, the amounts of fat and/or lactose usually increase. Individuals with lactose intolerance should avoid whey protein concentrates as they usually contain lactose and the amount can vary greatly from product to product.
Isolates are processed to remove the fat and lactose, but are usually lower in bioactive compounds as well--they are 90% or more protein by weight. Whey protein isolate is the purest and most concentrated form of whey protein available. It contains 90% or more protein and very little (if any) fat and lactose. Compared to other proteins, on a gram-to-gram basis whey protein isolate delivers more essential amino acids to the body but without the fat or cholesterol.
Hydrolysates are predigested, partially hydrolyzed whey proteins that, as a consequence, are more easily absorbed, but their cost is generally higher. Whey protein hydrolysate also tends to taste quite different from other forms of whey protein, usually in a way that many find undesirable, but the taste can be masked when hydrolysates are used in beverages.
Denatured and Undenatured Whey Protein: High heat (160˚F) associated with pasteurization denatures whey proteins. This process destroys some bioactive compounds, such as the amino acid cysteine. While native whey protein does not aggregate upon acidification of milk, denaturing the whey protein triggers hydrophobic interactions with other proteins. This causes the formation of disulfide bonds between whey proteins and casein micelles, leading to aggregation with other milk proteins at low pH. Undenatured whey protein is the unmodified form with highly ordered structure.5
Whey protein is rich in amino acids that provide many health benefits. The BCAAs that are provided in whey protein are metabolized directly into muscle tissues and start repairing and rebuilding lean muscle tissue. Whey is easy to digest for effective absorption by the body.6
Cancer: Patients with cancer often experience nausea and lack of appetite due to their treatment. This can cause multiple health issues including malnutrition. Weakened immune systems are also common in patients with cancer, and this makes them susceptible to infections and illness. Adding whey protein, which is rich in the amino acid cysteine, can provide a needed boost to the immune system by raising glutathione levels. Some individuals with suppressed immune systems or degenerative diseases use undenatured bioactive whey proteins to increase their antioxidant levels. In studies conducted on rats, whey protein has been shown to "inhibit the growth of several types of cancer tumors." It was shown to prevent tumors as well as slow the development of tumors.7
Diabetes and Weight Management: Maintaining a healthy weight is important for patients with diabetes. People who suffer from diabetes cannot consume high levels of carbohydrates. Due to the thermogenic effect, the body will burn more calories after a high-protein meal, leading to weight loss. Thus, since whey protein is both rich in protein and low in carbohydrates, it is a smart choice for patients with diabetes. Whey protein is also good for managing strong, lean muscles, which are essential for burning fat and losing weight. For people who are attempting to lose weight or build muscle, it is recommended that they increase the amount of protein in their diet. The protein from whey also helps to decrease the rate at which glucose is absorbed into the bloodstream; this aids in the maintenance of insulin levels.
Pediatric Use: Breast milk provides nutrients that are vital for newborn babies, but when breast-feeding is not an option, formulas that are whey protein-based are a great alternative. Whey contains many of the same elements as mother's milk. Amino acids offered by whey protein aid in the growth of beneficial organisms that can reduce the risk of gastrointestinal diseases in infants. Whey protein formulas have also been shown to reduce crying in infants who suffer from colicky pain. Whey protein is also beneficial for expectant mothers because the body's demand for protein increases by 33% during pregnancy. Whey protein is easy to take, has no flavor, and is easy to digest, making it a suitable candidate for the mother. Hydrolyzed whey protein is still a high-quality protein, and it is less likely to cause an allergic reaction in comparison to nonhydrolyzed whey protein. It is most commonly used in infant formulas and specialty protein supplements for medical use.8
Geriatric Use: As people age, they can lose their ability to effectively uphold strong bones and muscles. One way to achieve healthy bones and muscles is through a protein-rich diet. It is seen that elderly individuals who consumed low levels of protein had a significant loss of bone density, particularly in the hip and spine areas.
Wound Healing: In order to heal an open wound, the body demands extra amounts of proteins and amino acids. Without adequate or proper types of protein, the healing process may take longer. Whey protein is often recommended by physicians for burn victims or surgery patients to reduce healing time. Recently, companies have introduced oral health care products containing whey protein because of its antimicrobial properties. Whey protein amino acids can help reduce plaque buildup on teeth by trapping the bacteria that cause it.
Whey Protein and Surgery: Protein plays an essential role in the diet after surgery, as it is the primary food source. After bariatric surgery, it is important to follow a special diet designed by a physician and/or nutrition professional. Inadequate amounts of protein may contribute to hair loss, muscle loss, and poor skin tone. Whey protein isolate is an excellent protein choice after surgery as it is very easy to digest and is efficiently absorbed into the body. It does not sit in the stomach for long periods of time like meat and other protein foods that may upset the system.
Whey Protein and Pregnancy: Whey protein is a complete high-quality protein and should be an acceptable protein source for healthy pregnant women and children, provided they are not allergic to dairy proteins. The second most abundant component in whey protein is alpha-lactalbumin, which is one of the main whey proteins in human breast milk. Infant formulas often contain whey protein, including special formulas for premature infants. Prior to taking whey protein, both pregnant women and parents of young children should consult a physician to be sure whey protein is right for them.
Whey Protein and Bodybuilders: Whey protein is a common bodybuilding supplement. More than other protein supplements, whey protein powder is commonly used by bodybuilders and other athletes to accelerate muscle development and aid in recovery. The amino acids that are offered through whey protein aid in the building of muscle tissue. Supplements have been said to increase both hormonal and cellular responses as well. When exercise is paired with protein intake, the body will consistently build muscles. Athletes and body- builders who exercise often are likely to have depleted protein levels; when they take whey protein supplements, their protein levels will be replenished and their muscles will grow faster.
People often mistakenly think that high-protein diets cause kidney damage; however, there have not been any studies to support this claim. The abundant studies that have been conducted to test the benefits of whey protein have shown that no kidney damage has occurred from the use of whey. If kidney problems already exist, increased intake of protein can cause further damage, and it is suggested that protein be taken in moderation and with the consent of a doctor. Whey protein does have high vitamin content, so too much whey protein can create some problems with vitamin toxicity. There are no other documented side effects of taking whey protein supplements unless the person is allergic to dairy products.9 Individuals with lactose intolerance should select a pure whey protein isolate, which has less than 0.1 g of lactose per tablespoon (15 g).
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