A Bit of Biochem
For those of you who equate biochemistry with a bad dream, I will briefly refresh your memory. Our bodies manufacture creatine from the amino acids arginine, methionine, and glycine. Then a phosphate molecule is added to form creatinine phosphate. When we perform strenuous anaerobic activities such as weightlifting or sprinting, we get our energy from ATP stored in our muscles. As ATP is quickly used (the loss of phosphate for energy forms ADP) it can be immediately reformed with the phosphate from creatinine phosphate, which is stored in muscle. This process is faster than glycolysis or oxidative phosphorylation.1
Those of you who have lifted weights, think how you feel when you get to the last repetition in your set. If you had more ATP, that repetition would not be your last because you would not yet have had to turn to glycolysis for energy; thus, no lactate and pyruvate would be in your muscles causing the burn and fatigue. In other words, you could do more repetitions before your muscles fatigued. With proper diet and rest, the ability to lift more weight equates to greater gains in muscle size and strength.
Creatinine ingested orally raises the amount in tissue with muscle tissue receiving the highest amount. Even more exciting was the fact that the muscles of weightlifters had greater increases than the muscles of nonweightlifters.2
The above study dose was 5 gm taken four to six times per day (20 to 30 gm per day for two days). Thirty grams of anything is quite a bit. However, 10 gm a day for 10 days can also lead to significant increases in muscle creatinine levels.3 Although there is no evidence, I wonder what 5 or 6 gm per day (a more realistic dose for compliance purposes) would do after 30 days.
Although some stores sell ATP and some products contain it, oral ingestion does not raise tissue levels (it doesn't make it through the gut).4 Red meat is the best dietary source of creatinine (a two pound steak has approximately 5 gm).5 But who is going to recommend two to four pounds of steak per day?
After finishing this piece, it makes me want to take creatinine myself. However, I am extrapolating, because there are no studies out yet to either confirm or deny our theory that creatinine may be the supplement anaerobic athletes have been looking for. I will keep you posted.
- Martin, Mayes, Rodwell, and Granner. Harper's Review of Biochemistry. Lange Medical Publications, Los Altos, California, 1985.
- Harris, Soderlund, and Hultman. Elevation of creatinine in resting and exercise muscle of normal subjects by creatinine supplementation. Clinical Science, 83, 1992.
- Bucci. Nutrients As Ergogenic Aids for Sports and Exercise. CRC Press, Boca Raton, Florida, 1993.
- Cadena. Boosting Performance with creatine. Muscle Media 2000. Mile High Publishing, Golden, Colorado. No 32, June/July, 1993.
- Leibovitz. Creatinine, energy-storing molecule in muscle and ergogenic aid. Muscular Development. Advanced Research Press, New York. 30:(11), 1993.
G. Douglas Andersen, DC
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