Most people are aware of the role of amino acids play in our nutrition. They know that amino acids are a component of proteins and essential to muscle growth. Yet the exact mechanisms behind this amino acid/muscle connection may be less well known. We will explain it here. In the process, we’ll also show the importance of amino acids and highlight the incredible level of activity going on in our cells during exercise. We’ll focus on three particular amino acids, all of have been shown to aid muscle function during exercise: L-Ornithine, L-Arginine, and L-Carnitine.
What Are Amino Acids?
Amino acids are defined as “organic compounds that combine to form proteins.”[1] As to how they do it, here is a brief overview: the body digests protein and breaks it down into amino acids, then uses these amino acids to build new protein. The entire process is known as protein biosynthesis.
Protein controls virtually all cellular processes. As the building blocks of protein, amino acids are responsible for many vital functions. Amino acids give cells their structure, transport and store nutrients, remove waste, repair tissue, and help the body grow.
There are twenty amino acids. Of those, our bodies can produce nine. The amino acids produced by the body are called “nonessential.” Those that cannot be produced by the body are called “essential” and must be obtained from food.
The importance of getting these essential amino acids cannot be understated. The body does not store amino acids for later use, as it does with other nutrients, so we must consume adequate amounts of amino acids every day, or use supplements to reach the necessary levels. If the body is lacking even one essential amino acid, it will seek it within muscle and other tissues, leading to possible degradation of these tissues.[2],[3]
Exercise, Oxidative Stress, and Amino Acids
To understand how amino acids help muscle growth, it is necessary to discuss the effects of exercise on the body’s cells and tissues.
Acute exercise damages muscles, causing little tears. It is during the act of repairing muscle that new, bigger muscle tissue is built. As with any type of injury to the body, the damage caused by exercise causes inflammation. This inflammation is induced by excessive production of reactive oxygen and nitrogen species, called ROS and RNS respectively.[4] The overproduction of ROS and RNS results in a condition known as oxidative stress. Together, oxidative stress and inflammation can impair muscle function and lead to muscle fatigue.
Ammonia is one specific nitrogen-containing compound that has an effect on muscles. Prolonged exercise can lead to excess levels of ammonia in skeletal muscle; that is, the type of muscle that contracts and extends during exercise. Excess ammonia can affect the muscle’s ability to contract while also causing fatigue.
There are three amino acids that help regulate ammonia concentrations in the body. L-Arginine, an essential amino acid, is converted to L-Ornithine, which is then converted into L-Citrulline. This conversion process causes an increase in urea and a corresponding decrease in ammonia. Also known as the urea cycle, this conversion is considered a nitrogen detoxifying process. In the context of exercise, it “detoxifies” by eliminating the ammonia that contributes to muscle fatigue.[5]
For its part, L-Arginine plays another important role. It is used by the enzyme eNOS to create nitric oxide, a substance that has been shown to improve exercise capacity by dilating blood vessels, thereby increasing blood flow and energy levels.[6],[7]
Another amino acid that has been proven beneficial when used in conjunction with exercise is L-Carnitine. Research has shown that L-Carnitine can increase fat burning during exercise.[8] L-Carnitine also appears to reduce muscle damage during anaerobic exercise, like sprinting and heavy weight lifting. Studies have shown that this nonessential amino acid increases the oxygenation of muscle tissue, which reduces damage and speeds up recovery times.[9] As one study concludes: “There is evidence for a beneficial effect of L-carnitine supplementation in training, competition, and recovery from strenuous exercise and in regenerative athletics.”[10]
As amino acids, L-Arginine, L-Ornithine, and L-Carnitine are found in protein-rich foods like meat, fish, eggs, and dairy. Since it is critical to get adequate amounts, supplements are another option (such as BLVCK Supplements, ‘XPLODE’). A 2014 article notes that a balanced diet is essential, but “there is growing evidence that some non-synthetic supplements can assist optimal nutrition…. The use of proteins and amino acids for supplementation deserves special attention, since these molecules are critical for anti-oxidant and fuel provision, participating in the whole-body energy homeostasis, growth, development, recovery and immune responses.”[11]
If you exercise regularly, chances are you already have a very healthy diet. But, as we’ve seen here, exercise can stress the body. Amino acids, like the three we describe in this article, can help alleviate that stress. Supplements are an excellent source for ensuring you are getting enough.
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References
[1] Medline Plus. “Amino acids” Medical Encyclopedia. https://medlineplus.gov/ency/article/002222.htm Accessed Oct. 24, 2017.
[2] The Biology Project. “The Chemistry of Amino Acids.” Department of Biochemistry and Molecular Biophysics, University of Arizona. http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html Accessed Nov. 10, 2017.
[3] Medline Plus.
[4] Cruzat, V.F. et al. “Amino acid supplementation and impact on immune function in the context of exercise” Journal of the International Society of Sports Nutrition. 11, no. 61, 2014.
[5] Examine.com. “Ornithine” https://examine.com/supplements/ornithine/ Accessed Nov. 10, 2017.
[6] Yavari, Abbas et al. “Exercise-Induced Oxidative Stress and Dietary Antioxidants” Asian Journal of Sports Medicine. 6, no. 1, March 2015.
[7] Marie, Joanne. “What Does the Amino Acid L-Ornithine Do? LiveStrong. Aug. 14, 2017. https://www.livestrong.com/article/22017-amino-acid-l-ornithine/ Accessed Nov. 10, 2017.
[8] Gorostiaga, E.M. et al. “Decrease in respiratory quotient during exercise following L-carnitine supplementation.” International Journal of Sports Medicine. 10, no. 3, June 1989. p. 169-74.
[9] Examine.com. “L-Carnitine.” https://examine.com/supplements/l-carnitine/ Accessed Nov. 10, 2017.
[10] Karlic H. and A. Lohninger. “Supplementation of L-carnitine in athletes: does it make sense?” Nutrition. 20, no. 7-8. Jul-Aug, 2004. P. 709-15.
[11] Cruzat et al.