Creatine is a molecule found naturally in the body, produced by the liver and kidneys. It travels in the blood stream and is found in highest concentrations in muscle and nerve cells. Creatine is a popular supplement, used for athletic performance enhancement. It is more effective for certain types of exercise, however. If you are considering a creatine supplement, talk to your doctor first.
Mechanism
Creatine travels to the muscle cells, where a phosphate group is added to make creatine phosphate. When muscles contract, they use up ATP, adenosine triphosphate, which loses a phosphate to become ADP, adenosine diphosphate. Creatine phosphate supplies a phosphate to regenerate ATP. The more creatine phosphate in the cell, the more, and faster, ATP can be regenerated.
Sources
The body's own synthetic functions are enough to supply a necessary amount of creatine to regenerate ATP. Creatine is also found in some foods, and is highest in red meat. However, to get the benefits for athletic enhancement, it is taken as a supplement, since there is not enough made by the body or in foods to obtain these benefits.
Uses
Creatine is used by many types of athletes, but it is most effective for exercise involving short bursts of energy, called anaerobic activities. Creatine is used, for example, by weight lifters, sprinters and wrestlers. It is not effective for long distance activities such as distance running or biking, which are aerobic activities.
Effects
A 2002 review of studies published in "The Journal of Family Practice" concluded that creatine supplementation appears to be useful in young men under the age of 35. Its beneficial use in older men and women is not established. It appeared to increase weight lifted during compound weight exercises that work multiple muscle groups, such as squats and bench presses, more than isolated lifts such as biceps curls. It can also affect other short-term activities such as a sprint. However, it is important to consult with a physician prior to starting to use creatine.
References
- "Lehninger Principles of Biochemistry"; David L. Nelson, et al.; 4th Ed 2004
- "Molecular Biology of the Cell"; Bruce Alberts et al.; 4th Ed 2002
- "Physiology"; Linda S.Costanzo; 4th Ed 2008
- "The Journal of Family Practice"; Does oral creatine supplementation improve strength? A meta-analysis; Dempsey et al; 2002
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