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Protein Supplements


General Overview of Protein Supplements


The amino acids are the building blocks of proteins which are important macronutrients in human nutrition, providing structure for tissues, enzymes to catalyze reactions, hormones used for organ signaling, maintaining fluid balance, acid-base balance, molecular transport, immune function, and can also act as neurotransmitters (Lindshield, 2018). The importance of amino acids and proteins in the human diet is very clear based on their functions, and it is also a testament as to why there are so many companies making and selling different types of protein supplements. Most healthy people will not require supplemental protein, some adults may require an increasing amount of supplemental protein as they age past their third decade of life to help with declining physical health (Lonnie, et al., 2018). For infants and children from 1-3 years of age, the recommended daily allowance is 1.05 g/kg/d of protein, and from 4-13 years of age it is .95 g/kg/d of protein, from 14-18 years of age it is .85 g/kg/g of protein, for 19-70< years of age it is .80 g/kg/d of protein (Institute of Medicine of the National Academies, 2005). Athletes and elite athletes will have a higher protein requirement and supplementing their diet with protein will provide performance and body composition benefits (Hoffman & Falvo, 2004). The overweight population may also benefit from protein supplementation, as increasing protein intake and decreasing carbohydrate intake has been shown to increase satiety and decrease voluntary calorie intake (Hoffman & Falvo, 2004).


With regards to protein supplements, there are three main types of protein supplements which include whey protein, casein protein, and soy protein. Whey protein is derived from cow milk after it has been coagulated and the curd has been removed during the manufacturing of cheese. Whey protein is a complete protein with all essential amino acids and has high levels of essential and branched chain amino acids and is also rich in vitamins and the minerals calcium and phosphorous. Whey protein is further separated into whey powder, whey concentrate, and whey isolate depending on the level of processing involved. The least processed form of whey is whey powder which has around 10-15% protein concentrations, and once it goes through processing to remove water lactose, ash, and some minerals it becomes whey concentrate with about 25-90% protein. Whey isolates are the purest form and also have fat and more lactose removed, and has protein concentrations over 90% (Hoffman & Falvo, 2004).


Casein protein is the major protein constituent of cow milk and also a complete protein and also contain calcium and phosphorous. The unique property of casein is that it exists in a micelle form and can form a gel in the stomach, giving it the property of a slow sustained release nutrients and better nitrogen retention (Hoffman & Falvo, 2004). Soy protein is the most widely used protein, and while it is rated as a lower quality protein compared to the animal sources of protein based on anabolic growth, it has been rated as equal to animal proteins based on its digestibility (Hoffman & Falvo, 2004). Soy is the ideal vegetarian supplemental protein source or for those who are lactose intolerant, as it is also a complete protein with a high concentration of branched chain amino acids (Hoffman & Falvo, 2004). Similar to whey protein, soy protein is also differentiated into types based on the level of processing, with soy flour being the least processed and having about 50% protein concentration, soy concentrate with fats removed and containing about 70% concentration of protein, and finally soy isolate with fat and fiber removed and having a 90% protein concentration (Hoffman & Falvo, 2004).


These supplements are very helpful if used in combination with physical activity, and as demonstrated by high-protein and low-carbohydrate diets such as the Atkin’s Diet, protein can be used to help with weight loss (Hoffman & Falvo, 2004). Protein supplementation with branched chain amino acids has also be shown to improve older adults with age-related sarcopenia, or muscle loss (Lonnie, et al., 2018).

It is important to note that protein supplementation can also cause harm, and care must be taken to ensure proper utilization is practiced. By seeing a medical provider or certified nutritional specialist, complications from protein supplementation can be avoided. High protein diets can increase the risk of metabolic, cardiac, renal, bone, and liver diseases (Hoffman & Falvo, 2004). Metabolic ketosis occurs when fats are used for energy more due to insufficient carbohydrates, leading to increased ketones in the body leading to metabolic acidosis with complications of coma and death (Hoffman & Falvo, 2004). High protein diet can also cause abnormal lipid balances in the body and increasing blood pressure leading to increased risk of cardiac disease (Hoffman & Falvo, 2004). A high protein diet also increases the strain on the kidneys, and while a healthy individual without any renal problems will not experience renal dysfunction from high protein intake, someone with impaired kidney function may lead to an increase in kidney disease (Hoffman & Falvo, 2004). In general, it is again important to have some guidance from a nutrition professional to determine the safety and efficacy of protein supplementation.


Hoffman, J. R., & Falvo, M. J. (2004, May 26). Protein - Which is Best? Journal of Sports Science and Medicine, pp. 118-130.

Institute of Medicine of the National Academies. (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington D.C.: The National Academies Press.

Lindshield, B. (2018). Kansas State University Human Nutrition (FNDH 400) Flexbook. Manhattan: New Prairie Press.

Lonnie, M., Hooker, E., Brunstrom, J. M., Corfe, B. M., Green, M. A., Watson, A. W., . . . Johnstone, A. M. (2018, March 16). Protein for Life: Review of Optimal Protein Intake, Sustainable Dietary Sources and the Effect on Appetite in Ageing Adults. Nutrients, pp. 1-18.

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