Creatine: the almighty sports supplement

School Of Nutrition Posted Jan 19, 2015 Future Fit Training


Creatine is taken to increase their strength and power. It became popular during the 1992 Olympics, when British sprint athletes reported its benefits.

Creatine: the almighty sports supplement

Creatine has been recognized as the most effective nutritional supplement in enhancing exercise tolerance, muscle strength and lean body mass. But what is creatine and why is it so effective?

What is creatine?

Creatine is chemically known as a non-protein nitrogen. It is found naturally in meat, poultry and fish. These foods provide around 4-5g of creatine for every kg you consume. The body is able to manufacture any additional requirement from the amino acids arginine, glycine and methionine. Because vegetarians and vegans receive no creatine from their diets, their bodies manufacture all the creatine they need.

Approximately 95% of the body's creatine is stored in skeletal muscle. About two thirds of the creatine found in skeletal muscle is stored as phosphocreatine (PCr) while the other third is stored as free creatine. The total creatine pool (PCr + free creatine) in skeletal muscle averages 120g for a 70kg individual. The body breaks down about 1-2% of the creatine pool every day (about 1-2g/day) into creatinine in the skeletal muscle. The creatinine is then excreted in urine.

Dietary supplementation of creatine provides an inexpensive and efficient means of increasing dietary availability of creatine without excessive fat and/or protein intake from foods. Creatine can be taken as the supplement creatine monohydrate (CM), or added to other supplements or sports foods such as meal replacement drinks.

What are the benefits of creatine supplementation?

Creatine is taken by athletes who want to increase their strength and power. CM appears to be the most effective nutritional supplement currently available in terms of improving lean body mass and anaerobic capacity. [1] Long-term CM supplementation appears to enhance the overall quality of training, leading to 5 to 15% greater gains in strength and performance. [2] Basically, athletes gain muscle mass because creatine enables them to perform more sets/reps of high intensity exercise and train harder than they could manage without it.

CM has the advantage of being considered legal by the leading sports governing bodies including the International Olympic Committee (IOC), so clients can use it in preparation for sports competitions.

Why is creatine effective?

Creatine is effective because it acts on the phosphocreatine energy systems that power short bursts of high intensity activities such as sprints and weightlifting. Biochemically speaking, the energy supplied to re-phosphorylate adenosine diphosphate (ADP) to adenosine triphosphate (ATP) during and following intense exercise is largely dependent on the amount of phosphocreatine stored in the muscle. As phosphocreatine stores become depleted during intense exercise, energy availability diminishes due to the inability to resynthesize ATP at the rate required to sustained high-intensity exercise. Consequently, the ability to maintain maximal-effort exercise declines. The availability of phosphocreatine in the muscle significantly influences the amount of energy generated during brief periods of high-intensity exercise. [3]

Studies have shown that daily supplementation with high doses of creatine (20-30g) for two weeks will increase the levels of free creatine and phosphocreatine in muscle cells by 10-30%. The free creatine and phosphocreatine levels will remain high for weeks after the initial two weeks of creatine supplementation. [4]

Are there any health implications of long term creatine supplementation?

Studies to date show no adverse effects of creatine supplementation in healthy adults. However, care should be taken if working with athletes with known risk or pre-existing kidney dysfunction. Much of the concern about CM supplementation and renal function has centered on concerns over increased creatinine levels. While creatinine must be excreted by the kidneys, there is no evidence to support the notion that normal creatine intakes (< 25g per day) in healthy adults cause renal dysfunction.  Furthermore, studies have shown no detrimental effects of short- (5 days), medium- (14 days), or long-term (10 months to 5 years) CM supplementation on renal function. [5,6]

Conclusion

It is the position of the International Society of Sports Nutrition that the use of creatine as a nutritional supplement within established guidelines is safe, effective, and ethical. Hundreds of studies have shown the effectiveness of CM supplementation in improving anaerobic capacity, strength, and lean body mass in conjunction with training. In addition, CM has repeatedly been reported to be safe.

You can learn more about creatine, its beneficial effects, recommended creatine loading strategies and how to maximise muscle uptake and retention of creatine in the Nutrition for Sports and Exercise course.

Written by Victoria Trowse

REFERENCES:

1. Burford TW, et al. (2007). International Society of Sports Nutrition position stand: creatine supplementation and exercise. J Int Soc Sports Nutr. 4: 6.

2. Kreider RB. (2003). Effects of creatine supplementation on performance and training adaptations. Mol Cell Biochem. 244: 89–94.

3. Hultman E, et al. (1990). Energy metabolism and fatigue. In: Taylor A, Gollnick PD, Green H, editor. Biochemistry of Exercise VII. Human Kinetics: Champaign, IL; pp. 73–92.

4. William D McArdle, et al. (2009). Sports and Exercise Nutriton 3rd edition.

5. Poortmans JR & Francaux M. (1999). Long-term oral creatine supplementation does not impair renal function in healthy athletes. Med Sci Sports Exerc. 31: 1108–1110.

6. Poortmans JR, et al. (1997). Effect of short-term creatine supplementation on renal responses in men. Eur J Appl Physiol. 76: 566–567.

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