taken from
http://www.thefactsaboutfitness.com/research/creatinesafety.htm Creatine has established itself as one of the most effective and popular supplements available for people wanting to build muscle and improve performance. However, there are concerns that creatine is unsafe. Are the stories about creatine side effects that often appear in the popular press based on fact or fiction?
Creatine is a very popular supplement. That's mainly because it accelerates gains in muscle size and strength compared to exercise alone. In a 12-week trial by Jeff Volek and a research team from Pennsylvania State University, creatine users ended up stronger in both the squat and bench press compared with subjects using a "dummy" supplement [9]. They also gained twice as much muscle.
Creatine side effects
There are claims that creatine users are more susceptible to cramps, muscle spasms, and even pulled muscles. However, in a three-year study designed to find out whether these creatine side effects really do exist, creatine had no effect on the incidence of injury or cramping in a group of American footballers [2].
Research published in the journal
Medicine and Science in Sports and Exercise shows similar results [3]. In a group of 26 athletes using creatine for up to four years, there was no difference in the reported incidence of muscle cramp or injury compared with athletes not using creatine.
A more recent study, published in the September 2004 issue of the
International Journal of Sports Medicine, also shows that creatine side effects are rare [11].
A group of 175 subjects received either 10 grams of creatine or placebo daily for an average period of 310 days. Diarrhea and nausea did cause three subjects to stop using creatine. But there were no other significant differences between the groups.
Researchers from Truman State University also report that long-term creatine use appears to be safe [7].
Twenty-three members of an NCAA Division II American football team were divided into a creatine group and a control group who took no supplements.
Subjects in the creatine group averaged 14 grams of creatine a day for three years. However, the researchers could find no detrimental effects on either kidney or liver function.
Most people aren't aware that creatine has protective effects in heart, muscle and neurological diseases. In fact, several months of creatine supplementation in men and women with borderline high cholesterol levels reduces very-low-density lipoprotein levels (the so-called "bad" cholesterol) by almost one-third [1].
Similar findings are reported in the journal
Metabolism. Twenty-eight days of creatine supplementation and resistance exercise lowered total cholesterol levels to a greater extent than resistance exercise alone [10].
The bottom line
Carefully controlled studies over the short- (five days), medium- (nine weeks) and long-term (up to five years) have yet to demonstrate that creatine supplementation has any adverse effects on blood pressure, kidney or liver function in healthy individuals [3, 5, 6, 7, 8].
References
1. Earnest, C., Almada, A., & Mitchell, T. (1996). High-performance capillary electrophoresis-pure creatine monohydrate reduces blood lipids in men and women.
Clinical Science,
91, 113-118
2. Greenwood, M., Kreider, R.B., Melton, C., Rasmussen, C., Lancaster, S., Cantler, E., Milnor, P., & Almada, A. (2003). Creatine supplementation during college football training does not increase the incidence of cramping or injury.
Molecular and Cellular Biochemistry,
244, 83-88
3. Schilling, B.K., Stone, M.H., Utter, A., Kearney, J.T., Johnson, M., Coglianese, R., Smith, L., O'Bryant, H.S., Fry, A.C., Starks, M., Keith, R., & Stone, M.E. (2001). Creatine supplementation and health variables: a retrospective study.
Medicine and Science in Sports and Exercise,
33, 183-188
4. Pritchard, N.R., & Kalra, P.A. (1998). Renal dysfunction accompanying oral creatine supplements.
Lancet,
351, 1252-1253
5. Poortmans, J.R., & Francaux, M. (2000). Adverse effects of creatine supplementation: fact or fiction?
Sports Medicine,
30, 155-170
6. Kreider, R.B., Melton, C., Rasmussen, C.J., Greenwood, M., Lancaster, S., Cantler, E.C., Milnor, P., & Almada, A.L. (2003). Long-term creatine supplementation does not significantly affect clinical markers of health in athletes.
Molecular and Cellular Biochemistry,
244, 95-104
7. Mayhew, D.L., Mayhew, J.L., & Ware, J.S. (2002). Effects of long-term creatine supplementation on liver and kidney functions in American college football players.
International Journal of Sport Nutrition and Exercise Metabolism,
12, 453-460
8. Vannas-Sulonen, K., Sipila, I., Vannas, A., Simell, O., & Rapola, J. (1985). Gyrate atrophy of the chloroid and retina: a five year follow-up of creatine supplementation.
Opthalmology,
91, 1719-1727
9. Volek, J.S., Duncan, N.D., Mazzetti, S.A., Staron, R.S., Putukian, M., Gomez, A.L, Pearson, D.R, Fink, W.J., & Kraemer WJ. (1999). Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training.
Medicine and Science in Sports and Exercise,
31, 1147-1156
10. Arciero, P.J., Hannibal, N.S. 3rd, Nindl, B.C., Gentile, C.L., Hamed, J., & Vukovich, M.D. (2001). Comparison of creatine ingestion and resistance training on energy expenditure and limb blood flow.
Metabolism,
50, 1429-1434
11. Groeneveld, G.J., Beijer, C., Veldink, J.H., Kalmijn, S., Wokke, J.H.J., & van den Berg, L.H. (2004). Few adverse effects of long-term creatine supplementation in a placebo-controlled trial.
International Journal of Sports Medicine, 25