The Power of Protein - What Every Athlete Should Know
Protein is perhaps the most important of the three macronutrients we reference in How Managing Macronutrients Can Help You Control Body Weight, Composition. Derived from the ancient Greek word “Proteos” meaning “primitive” or “first,” protein plays a powerful role in our bodies.1
What Are Proteins?
Proteins are molecules made up of amino acids. Amino acids, compounds that contain carbon, oxygen, hydrogen and sometimes sulfur, are linked together in specific combinations to form each protein of our bodies and our foods.
Proteins are vital components of tissues, enzymes and immune cells. Making up approximately 20 percent of our body weight, proteins are the most abundant substances in our bodies next to water which comprises an astonishing 42-68% of body weight. 2
There are 20 known amino acids (the building blocks of protein) but the human body can only synthesize 11 on its own. These 11 are referred to as “nonessential” amino acids. Eight “essential” amino acids must be obtained from the diet. Histidine is a unique amino acid, sometimes classified as essential, because during particular periods of development, the body is unable to synthesize enough to keep pace with metabolic demands.
Nonessential Amino Acids Essential Amino Acids Alanine Isoleucine (Branched-chain amino acid) Arginine* Leucine (Branched-chain amino acid) Aspartate Lysine Cysteine Methionine Glutamate Phenylalanine Glutamine Threonine Glycine Tryptophan Proline Valine (Branched-chain amino acid) Serine Histidine* Taurine Tyrosine
*Sometimes classified as semi-essential amino acids because of their rate of synthesis in the body.
Why Do We Need Protein?
Proteins contribute to the following functions in the body:
- Maintenance of muscle, tendon, ligament, hair, skin and nail strength
- Synthesis of enzymes, biological molecules that catalyze various chemical reactions3
- Synthesis of hormones, chemical substances that act as messengers throughout various body tissues4
- Transportation of oxygen, minerals and vitamins to various body tissues
- Synthesis of lipoproteins which help transport fat and cholesterol
- Synthesis of antibodies, proteins vital to the immune system
- Maintenance of proper fluid and acid-base balance
Dietary Protein Is a Must
It is essential to obtain protein through the diet. Once digested, protein is broken down into its component parts, amino acids, which are then re-assembled into the proteins vital for the functions listed above. Protein is also used as a source of energy when we don’t consume enough carbohydrates or fats.5
For competing athletes, consuming an adequate amount of dietary protein is especially critical. The demands of rigorous training are high and while athletes want to build muscle, not break it down, with inadequate dietary protein, the body will turn to its natural sites of protein storage to recruit amino acids. Skeletal muscle is one such site. As the body mobilizes amino acids to carry out the vital functions listed above, the skeletal muscle we rely on for performance may be degraded.
What Happens If We Don’t Consume Enough Protein?
Deficiency in dietary protein may lead to muscle wasting and weakness. Protein deficiency can also impair recovery from exercise, is associated with exercise-related injury and immune dysfunction.6
Great Sources of Protein explores the best foods we can consume to obtain the protein we need.
Edited by Dr. Yetsa Tuakli
1Wikipedia. (2014, July 18). Proteus. Retrieved July 29, 2014, from Wikipedia: http://en.wikipedia.org/w/index.php?title=Proteus&oldid=617438684
2Wikipedia. (2014, July 13). Body water. Retrieved July 29, 2014, from Wikipedia: http://en.wikipedia.org/w/index.php?title=Body_water&oldid=616820712
3MedicineNet, Inc. (2013, October 30). Enzyme definition - Medical Dictionary: Definitions of Popular Terms Defined on MedTerms. Retrieved August 20, 2014, from MedicineNet.com: http://www.medterms.com/script/main/art.asp?articlekey=3266
4MedicineNet, Inc. (2002, October 23). Hormones: All About Hormones - MedicineNet - Health and Medical Information Produced by Doctors. Retrieved August 20, 2014, from MedicineNet.com: http://www.medicinenet.com/script/main/art.asp?articlekey=184
5National Academy of Sports Medicine. (2008). NASM Essentials of personal fitness training (3rd ed.). (M. A. Clark, S. C. Lucett, & R. J. Corn, Eds.) Baltimore, MD: Lippincott Williams & Wilkins.
6Annigan, J. (n.d.). Consequences of Low Protein Daily Intake | Health Eating. Retrieved July 30, 2014, from SFGate: http://healthyeating.sfgate.com/consequences-low-protein-daily-intake-6330.html
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