Protein Use in Sports Nutrition

Sports Nutrition is one of the fastest growing segments in both the functional foods and dietary supplement markets, and probably the most recognized ingredient in sports nutrition is protein. There is no doubt that protein is important in building muscle mass and in repairing injured tissue.

Protein supplements come in various forms, though the most common are protein powders. These powders are concentrated forms of protein and can be obtained from either plant or animal sources. They are typically sold in one of three forms. Protein concentrates are the closest to whole food and contain about 60-70% protein, with fat and carbohydrates making up the rest. Protein isolates are prepared by removal of the fat and carbs. Protein isolates contain at least 90% protein. Protein hydrolysates are produced by hydrolysis (heating, acid or enzymes) that breaks the amino acid bonds. Hydrolysates consist of mixtures of oligopeptides, peptides and free amino acids. They are reportedly more easily absorbed into circulation and used by the body.[1]

Protein supplements are easy to find and there are lots of options for the source of the protein and the form in which is it sold; but, just like other supplement ingredients, not all of them are beneficial or even safe. To ensure the best benefits from consuming a protein supplement, consumers of these products should consider several important factors.

One important consideration for persons selecting protein supplements to improve sports performance is the selection of products that contain complete proteins, containing all nine essential amino acids. Probably the most popular single source for complete protein is whey. Whey is derived from milk and has the advantage of being easily digested and absorbed. It is rich in branched-chain amino acids (BCAAs), which play an important role in muscle development and exercise recovery. However, whey protein concentrate contains the milk sugar, lactose, which can be problematic for those who are lactose intolerant. Selecting an isolate can help overcome this obstacle. Another popular dairy protein is casein. Casein is absorbed more slowly than whey and may help slow down muscle breakdown during intense exercise. Both whey and casein are commodity ingredients so quality issues and adulteration are possible.

One of the best sources of complete protein that is also suitable for some vegetarians is egg protein. Eggs have the highest PDCAAS or “protein digestibility-corrected amino acid score”, which measures a protein’s quality and digestibility. Egg protein also is second only to whey in its content of leucine, the BCAA that plays the largest role in muscle health. Usually, egg protein is derived from the egg white, which contains the highest proportion of protein and minimal fat, as the fat in eggs is found almost exclusively in the yolk.

Another part of the egg that is beginning to get increased attention is the eggshell membrane. This thin, fibrous, protective, dual layer of the egg is mostly protein and is rich in nutrients, including Types I, V and X collagen and several important glycosaminoglycans, such as chondroitin sulfate and hyaluronic acid. Recent research has also indicated that unhydrolyzed eggshell membrane might function like a prebiotic source capable of beneficially increasing gut diversity.[2]

For vegans and vegetarians who don’t consume animal products, selecting a complete protein source might be more of a challenge. Soy protein contains all nine essential amino acids and is a very popular protein source, though it does have several drawbacks including its GMO status, allergenicity and digestibility, and its content of natural estrogens. Fermentation of the soy helps overcome some of these disadvantages. Pea Protein is another common vegetarian protein source. It contains all nine essential amino acids, though methionine is often very low or absent from some forms. Pea protein is rich in BCAAs. Other good plant proteins include hemp, chia and rice. To ensure a complete plant protein supplement, often there will be a mixture of proteins from different plant sources.

Shorter chain protein peptides, typically from beef or chicken, particularly collagen peptides, are also popular protein supplements for athletes and others who purchase supplements to help improve sports performance and offset fatigue. Most collagen peptides are hydrolyzed (partially or completely broken down) to make them easier to absorb through the intestinal wall. These specialized protein supplements may provide support for both joints and bones and help boost muscle mass.

One area that is often neglected when either marketing or purchasing a protein supplement is consideration of the fact that it is possible to consume too much protein for our bodies to adequately break down and absorb. Our bodies break down protein quite efficiently provided our gastric, pancreatic and intestinal digestive mechanisms are functioning as they should. But even a minor digestive disruption such as insufficient gastric acid (a real problem for those who must take acid neutralizers) can drastically impact the efficiency of protein digestion, sending too much undigested protein to the colon, where it can be fermented by certain colonic bacteria, potentially producing toxic compounds.[3] A reasonable goal for most is around 15-25% of total daily calories, but this also depends upon age, sex, and activity level.[4]

There is no doubt that protein plays a vital role in supporting the nutritive needs for athletes and others desiring to maintain a healthy, active lifestyle, particularly after middle age. With proper care and consideration, selecting the right protein supplement can be a critical tool in achieving these goals.


[2] Jia H et al. (2017) Eggshell membrane powder ameliorates intestinal inflammation by facilitating the restitution of epithelial injury and alleviating microbial dysbiosis.

[3] Diether NE and Willing BP (2019). Microbial fermentation of dietary protein: an important factor in diet-microbe-host interaction. Microorganisms 7, 19.