Creatine as a Dietary Supplement for Athletes and Bodybuilders

Introduction to Creatine Use Among Athletes

Creatine is a dietary supplement that has been popular for more than thirty years among athletes and bodybuilders (Feldman 1999: 45). Its alleged benefits include enhancing muscle-building and recovery. The use of dietary supplements, particularly among adolescents and young adult athletes, has increased in popularity and may even be endorsed by coaches and parents. Creatine is not recommended for young athletes because of questions about the long-term safety of its use, but pressures to "be the best" have increased as the margin between first-class and second-class athletes grows ever more razor-thin (Dunn et al. 2001). One study found that "62% of adolescent athletes believed supplements improve performance, with 50% consuming dietary supplements" (Dunn et al. 2001). In another study of the attitudes of young athletes, Dunn et al. (2001) found widespread acceptance of creatine use and belief in its benefits, even among athletes who did not use other ergogenic aids.

Use of creatine is even more common in the elite ranks of athletes. Among NCAA athletes, according to LaBotz & Smith (1999), "forty-eight percent of men reported having used creatine as compared with 4% of women. With two exceptions, all men's teams had at least 30% of athletes who reported a history of creatine use." Creatine is also popular among recreational bodybuilders, who often ingest it through over-the-counter supplements.

The greater popularity of creatine use among males is likely because creatine is mainly effective in anaerobic sports that require muscle-building — such as football and rugby — versus endurance activities. In fact, "creatine biosynthesis rates are highest under anabolic conditions in young vertebrates with a good food supply and optimal levels of blood insulin, somatotropin, thyroxin, and testosterone" (Feldman 1999: 46). Research indicates that creatine provides no benefit for endurance sports such as long-distance running. For sports in which aesthetics are a concern — such as gymnastics and figure skating — female athletes may be deterred by the weight gain that is one of the side effects of creatine (Feldman 1999: 46).

Biochemistry and Natural Production of Creatine

Creatine is produced naturally in the body. It is "an amino acid that in its phosphorylated form transfers phosphate to adenosine diphosphate (ADP) to maintain high levels of adenosine triphosphate (ATP) in muscle and thus provides energy for muscle activity" (Feldman 1999: 45). Creatine is transported to muscle and nerve tissue and crosses the cell membrane via a specific creatine transporter. Approximately half a pound of meat contains roughly 1 g of creatine. It has been shown that during consumption of a creatine-free diet, the body can synthesize the necessary amount. Creatinine does not remain in muscle but is distributed throughout body water and is rapidly excreted in the urine. There is no renal threshold for urinary excretion of creatinine (Feldman 1999: 46). Creatine can be obtained through eating meat and fish, but "dietary supplementation of creatine provides an inexpensive and efficient means of increasing dietary availability of creatine without excessive fat and/or protein intake" (Buford et al. 2007).

The International Society of Sports Nutrition takes the position that "creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training," and states that the supplement is not only safe but is recommended to prevent injury and manage medical conditions that affect exercise capacity (Buford et al. 2007).

Research Study Reviews

The findings of research studies on the benefits of creatine are mixed. One small study by Tarnopolsky & MacLennan (2000) found that benefits exist for both males and females. Twelve males and twelve females were given creatine monohydrate "using a randomized, double-blind crossover design (7-week washout)… significant main effects of creatine treatment included: increased peak and relative peak anaerobic cycling power (3.7%; p < .05), dorsiflexion MVC torque (6.6%; p < .05), and increased lactate (20.8%; p < .05) with no gender-specific responses."

Once again, it should be noted that these gains were anaerobic in nature. A report by Buford et al. (2007), published by the International Society of Sports Nutrition, found that "weight gain associated with creatine monohydrate supplementation could be detrimental in sports such as running or swimming," although for other sports "the average gain in performance from these studies typically ranges between 10 to 15% depending on the variable of interest." On average, the Society reported that athletes supplementing with creatine gain twice as much lean muscle mass as those taking a placebo (Buford et al. 2007).

Not all studies have confirmed these findings. In another small study by Beck (2007), fifty-one men were assigned a creatine drink while others received a placebo. Neither group showed marked improvement on two 30-second Wingate Anaerobic Tests measuring peak power (PP) and mean power (MP), percent body fat, and fat-free mass, nor on tests of external resistance strength and muscular endurance over a ten-week period. However, none of these men were trained athletes, which may indicate that some natural capacity to build body mass must be present for the supplement to be effective.

Conclusion

The findings on how best to use creatine — in what doses, and in combination with what nutrients — remain mixed. Creatine should be used with caution, particularly by those with preexisting medical conditions. People with a history of kidney problems should avoid creatine, as there are reports that it can cause kidney damage (Mayo Clinic 2012). Used under careful supervision, creatine can apparently provide benefits, but the extent to which the risks outweigh the improvements in athletic performance remains a topic of intense debate and will depend on the individual. Although the only universally consistent detriment found in studies of healthy athletes has been weight gain, "many anecdotal claims of side effects including dehydration, cramping, kidney and liver damage, musculoskeletal injury, gastrointestinal distress, and anterior (leg) compartment syndrome still exist in the media and popular literature" (Buford et al. 2007). Simply because a supplement is "natural" does not mean it is risk-free or universally effective.

References

Beck, T. W., Housh, T. J., Johnson, G. O., Coburn, D. W., Malek, M. H., & Cramer, J. T. (2007). Effects of a drink containing creatine, amino acids, and protein, combined with ten weeks of resistance training on body composition, strength, and anaerobic performance. Journal of Strength and Conditioning Research, 21, 100–104.

Buford, T. W., et al. (2007). International Society of Sports Nutrition position stand: creatine supplementation and exercise. Retrieved from http://www.jissn.com/content/4/1/6

Creatine. (2012). Mayo Clinic. Retrieved from http://www.mayoclinic.com/health/creatine/NS_patient-creatine

Dunn, M. S., Eddy, J. M., Wang, M. Q., & Nagy, S. (2001). The influence of significant others on attitudes, subjective norms and intentions regarding dietary supplement use among adolescent athletes. Adolescence, 36(143), 583–591.

Feldman, E. (1999). Creatine: a dietary supplement and ergogenic aid. Nutrition Reviews, 57(2), 45–50.

LaBotz, M., & Smith, B. (1999). Creatine supplement use in an NCAA Division I athletic program. Clinical Journal of Sport Medicine, 9(3), 167–169.

Tarnopolsky, M. A., & MacLennan, D. P. (2000). Creatine monohydrate supplementation enhances high-intensity exercise performance in males and females. International Journal of Sport Nutrition and Exercise Metabolism, 10, 452–463.

Theodorou, A. S., Havenetidis, K., Zanker, C. L., O'Hara, J. P., King, R. F., Hood, C., Paradisis, G., & Cooke, C. B. (2005). Effects of acute creatine loading with or without carbohydrate on repeated bouts of maximal swimming in high-performance swimmers. Journal of Strength and Conditioning Research, 19, 265–269.