Creatine and the Athlete

What is creatine?

Creatine is an organic compound synthesized by a variety of amino acids. Our bodies naturally produce creatine and is found in various food sources. Creatine is most commonly used as an exercise performance enhancing supplement, also known as an ergogenic aid, in the form of creatine monohydrate. With adequate amounts of dietary creatine, the human body produces about 1-2g of creatine per day. (1)

Sources of creatine

Dietary sources of creatine are abundant in animal sources such as shrimp, milk, cod, tuna, beef, salmon, pork, and herring (1). Those who consume small quantities of meat products such as vegetarians and vegans are more than likely to have lower levels of creatine stores (1). Therefore, greater increases in creatine stores from creatine supplementation are found in those who consume vegetarian/vegan diets (1).

What creatine does

In our bodies, our source of energy comes from the molecules adenosine triphosphate and adenosine diphosphate (ATP and ADP) and only have limited stores within our muscles. Creatine is used in the creatine phosphagen system to create ATP very quickly when needed – for example, sprinting or performing a one rep max power lift.

There are several factors that affect the storage and utility of creatine within the body. Some main factors include the type of muscle fiber, amount of muscle mass, and gender. (2)

Creatine as an ergogenic aid

Creatine monohydrate is the form most commonly used as an ergogenic aid to support health and sports performance in athletes. When ingested, creatine monohydrate is shown to improve exercise performance and increase fat-free mass and muscle morphology (2).

In predominantly anaerobic exercise, creatine supplementation has been shown to be attributed to an increased creatine storage pool which results in faster ATP regeneration between resistance training sets (2). Thus, creatine has been shown to increase training capacity which likely leads to enhanced maximum and endurance strength and muscle growth (2).

Generally the benefits of creatine supplementation and sport performance are more commonly found in intense short-term repeated bouts of exercise (3). ·      Creatine supplementation with longer lasting exercise has been shown to have less benefits to performance. Although, faster sprint finishes at the end of endurance exercise like cycling have been observed (3).

Creatine supplementation has yet to have effects on increases in direct muscle protein synthesis or breakdown (3). Although, creatine may improve the adaptive response to training by supporting increased growth factor expression, satellite cell number, and intracellular water content (3). Therefore, supplementation of creatine monohydrate may also increase adaptation to intense training (3).

Creatine may also have benefits in injury recovery. Although creatine supplementation has yet to show direct effects on muscle protein breakdown, past studies have suggested that creatine hyper-hydrating muscle cells decrease muscle protein breakdown (4). Therefore, creatine supplementation may enhance recovery from injury by suppressing muscle protein breakdown due to inactivity (4). During mild traumatic brain injuries or concussion in sports, decreased brain creatine has been reported. It is suggested that adequate creatine stores may have beneficial effects on mild traumatic brain injury recovery (5).

Side effects

Clinical trials on the effects of creatine monohydrate supplementation have not been shown to have adverse effects on various body systems (3). According to the Gatorade Sports Science Institute, available data indicates that creatine monohydrate supplementation when used properly does not pose any threat to renal, muscular, and thermoregulatory systems (3).

Keep in mind - due to creatine supplementation’s correlation with hyper-hydration within muscle tissue, weight gain may be a potential side effect that may negate the beneficial effects on performance depending on the athlete’s sport (3).

Supplementation and dosing

It is not yet known what the exact dose of creatine supplementation is required to provide maximal benefits (3). Factors like gender, body mass, and type of muscle fibers play a factor in dose requirements. Clinical studies have shown that 3-5g per day of creatine monohydrate seem to be adequate to maintain elevated muscle creatine levels (3). Any excess creatine is excreted by the kidneys in urine.

Creatine uptake by muscle cells are insulin mediated. Therefore, consuming carbohydrates or carbohydrates in combination with proteins can increase the uptake of creatine in muscle cells (6).

Takeaways

• Creatine is a naturally occurring compound in our bodies and can be found in food sources like shrimp, milk, cod, tuna, beef, salmon, pork, and herring.

• Individuals who follow a vegetarian or vegan diet are likely to have lower stores of creatine and may benefit the most from creatine supplementation.

• Creatine is most commonly used in our bodies to create quick energy.

• Creatine is commonly used as an ergogenic aid to enhance physiological adaptability to exercise, injury recovery, and increase fat-free mass.

• Athletes who participate in quick, high-intensity, repeated bouts of exercise are more likely to benefit from creatine supplementation compared to endurance athletes.

• 3-5 grams per day of creatine monohydrate has been found to adequately replenish creatine stores within muscle tissue in most individuals.

• There are no known adverse side effects that are directly correlated with creatine monohydrate supplementation.

• Creatine supplementation has been found to cause weight gain due to its hyper-hydration effects on muscle tissue. Therefore, creatine supplementation may adversely affect performance depending on the sport.

Questions?

For more information on how creatine supplementation can benefit you, feel free to reach out and book an individual consultation with me!

References:

1.     Grande B., & Graves S. (2012). Creatine supplementation: forms, function, and effects. National Strength and Conditioning Association, 27(1), 62-68. DOI:10.1519/00126548-200502000-00012

2.     Cooper R., Naclerio F., Allgrove J., and Jimenez A. (2012). Creatine supplementation with specific view to exercise/sports performance: an udpdate. Journal of the International Society of Sports Nutrition, 9(33). https://doi.org/10.1186/1550-2783-9-33

3.     Rawson E.S. (2018). The safety and efficacy of creatine monohydrate supplementation: what we have learned from the past 25 years of research. Gatorade Sports Science Exchange, 31(186), 1-6.

4.     Snow R.J., & Murphy R.M. (2003). Factors influencing creating loading into human skeletal muscle. Exerc. Sport Sci, 31:154-158.

5.     Low S.Y., Rennie M.J., Taylor P.M.. (1996). Modulation of glycogen synthesis in rat skeletal muscle changes in cell volume. J. Physiol, 495:299-303.

6.     Vagnozzie R., Signoretti S., Floris R., Marziali S., Manara M., Amorini A.M. (2013). Decrease in N-acetylaspartate following concussion may be coupled to decrease in creatine. J Head Trauma Rehabil, 28:284-292.