Related Terms

• Casein protein powders, colostrum protein powders, egg protein powders, fish protein powders, protein shakes, rice protein powders, soy protein isolate, soy protein powders, U-Turn bars, whey protein powders.

Background

• Protein powder is a powdered and refined protein intensive dietary supplement used by fitness enthusiasts and muscle builders trying to increase muscle bulk and strength. It can be mixed into a liquid form for consumption as a protein shake, or sprinkled on top of cereal, mixed with soups or cooked into baked goods.

• Protein is necessary in the diet because of its role in muscle and tissue structure and function. Some examples of protein rich foods are meats, fish, dairy products, dried beans and peas, and tofu.

• Protein powders are usually made from one of four basic sources: whey (from milk), egg, soy or rice. Protein powders may be made from just one of these sources or may be a combination.

• The consumption of protein powder on a daily basis is thought by some to provide a number of nutritional and health benefits such as helping to boost the immune system and help with the healing process after an injury or after surgery.

Types of Protein Powders

• Egg, whey, and soy contain the full spectrum of essential amino acids. These compounds are termed "essential" because they cannot be produced through metabolic processes within the body but must be consumed daily from the foods. All three protein types also score equally highly on the PDCAAS (Protein Digestibility-Corrected Amino Acid Score), with a top ranking score of 1.0.

• Egg protein powder: Historically, egg protein powders were regarded as the gold standard of proteins, particularly among body builders. They should be avoided in those allergic to eggs or chicken.

• Rice protein powder: Rice protein powder is derived from the endosperm of grains by the process of separating proteins and carbohydrates. It is though to be the most hypoallergenic protein source, meaning that it produces the least allergic reactions. It has an excellent amino acid profile, very close to that found in mother's milk. Rice protein is also highly digestible and low in ash. It may be used to fortify bars, or it may be added to extruded (process by which feed has been pressed, pushed, or protruded through orifices under pressure) products, baked goods, meal replacement systems and nutritional supplements. It has also been used in cat and dog food, aquatic feeds, calf milk replacement and piglet food.

• Soy protein powder: Soy protein has been used for centuries in Asia as a nutritional source of protein and also as a medicine. The first use of soy formula in the United States was in 1909 when the soy protein based formulas used soy flour, which often caused gastrointestinal problems. In mid 1960, a soy protein isolate was used, reducing gastrointestinal problems. In October 1999, products containing soy became very popular when the U.S. Federal Food and Drug Administration (FDA) approved manufacturers to label soy protein products as helping to reduce the risk of heart disease. The structure of soy protein most closely resembles that of meat protein and therefore can provide an important meat substitute for vegetarians and those individuals wishing to regulate meat consumption.

• Whey protein powder: Whey is the watery part of milk that separates from the curds, as in the process of making cheese. Whey protein powder is a concentrated source of non-essential and essential amino acids provided in powder form. As a supplement, whey protein powder may be effective in increasing muscle tissue repair for body builders and athletes in general. High concentrations of branched chain amino acids are proposed to allow for direct uptake by muscle during exercise. Those allergic to milk products should not take whey protein powders. Whey is often the protein supplement of choice for athletes reliant on speed and stamina. It is also rich in tryptophan, a precursor of serotonin, which is commonly referred to as the "feel-good" neurotransmitter, and has been shown to lower stress levels and improve memory in experimental subjects.

• Other protein powders: Casein, fish, colostrums, and hemp protein powders are also available.

Theory/Evidence

• Protein powders have been found effective for helping HIV positive patients to maintain their weight.

• Scientists have found that soy protein may help reduce the risk of heart disease by lowering blood cholesterol and increasing the flexibility of blood vessels. The U.S. Food and Drug Administration (FDA) has approved a health claim stating that "25 grams of soy protein in a daily diet low in saturated fat and cholesterol can help reduce total and LDL cholesterol that is moderately high to high." Much of the human and animal research on the health benefits of soy has been conducted using isolated soy protein and supports the potential for short-term safety and efficacy. More research is necessary.

• Soy protein may benefit bone health by inhibiting fracture, preventing osteoporosis, or increasing bone mineral density, according to numerous animal and human studies. One such study, from the Vanderbilt University School of Medicine, Nashville, found an inverse relationship between consumption of soy foods and the risk of fracture among 403 postmenopausal women who had no history of fracture or cancer. Further, an Iranian study found soy protein consumption produced beneficial effects on bone metabolism indicators, leading the researchers to propose soy protein may have a preventive role in bone resorption, thereby preventing osteoporosis. A study at the University of Illinois at Urbana-Champaign was conducted on 66 postmenopausal women and found administration of high-isoflavone soy protein produced significant increases in bone mineral density at the lumbar spine.

• A study from Ohio State University, Columbus, compared the effect of consumption of soy and whey protein bars in athletes and found both the soy and whey groups showed a gain in lean body mass. However, the whey group, but not the soy group, showed a potentially deleterious post training effect on two antioxidant-related parameters, leading the researchers to conclude soy and whey protein bars both promoted exercise training-induced lean body mass gain, but the soy had the added benefit of preserving two aspects of antioxidant function.

• A study at Ball State University demonstrated that taking 0.88 grams of whey protein (used in U-Turn bars) per pound of body weight (cca 0.5 kilograms) results in increased prevention of overtraining. This may also be a good indication of the dosage that can be used to gain maximum whey protein effects.

• Recent studies on whey powder have focussed on muscle hypertrophy and resistance training in elderly males. Subjects who took whey protein powder immediately after exercise achieved positive results (less hypertrophy or muscle wasting) while those who took the formula two hours or more after exercise who had no significant change.

• Although certain types of protein powder appear beneficial for certain conditions, a more rigorous review of the scientific evidence is necessary before recommendations can be made.

Safety

• Protein powders are contraindicated in those allergic to any of the substances in the protein powder or those allergic to lactose or dairy products.

• The consumption of too much protein may be unhealthy. Protein is broken down in the body by the kidneys. If a person has kidney problems, the consumption of protein may need to be limited. The daily recommended consumption of protein is based on a patient's weight, age, and activity level.

• Dietary consumption of soy-based protein concentrate or soy isolate does not seem to be associated with any significant side effects other than mild gastrointestinal issues such as bloating and flatulence associated with any high protein diet.

• Whey protein has few documented side effects. However, whey protein may cause an allergic reaction in people suffering from lactose intolerance and should be avoided in those allergic to dairy products. Whey protein that can contain between 1% and 6% of lactose, depending on the type used. Severe or chronic whey protein over-ingestion can cause liver damage or failure.

• No safety profile has been established for children or pregnant or lactating woman. A qualified healthcare professional should be consulted before adding a protein powder or supplement to the diet.

Author Information

• This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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