Creatine short-term

The data on the long-term health effects of creatine supplementation is extremely limited. However, at least one animal study has found that creatine caused a decline in kidney function in rats with existing renal (kidney) disease. In addition, published case reports have indicated that creatine can cause further renal impairment in people with pre-existing kidney disease. However, several studies of healthy athletes have shown that both short-term and extended creatine supplementation had no effect on kidney function. 

Recent research has shown that oral creatine supplements not only increase creatine content in the muscle (the increase is greatest in exercised muscles) (ref.l), but delays fatigue (ref.2), improves recovery (by increasing the rate of phosphocreatine resynthesis in muscle) (ref.3), and increases muscle torque during repeated bouts of maximal voluntary exercise (ref.4). Other studies have shown that oral creatine supplements increases both power output and the total amount of short term work (ref.5). Creatine may also independently result in increased body mass (ref.6), although much of this increase seen in the first few weeks may be due to increased water retention. 

Exercise There is moxmting evidence that exercise might exacerbate statin-related side effects such as myopathy [50]. The randomised, controlled trial with 37 subjects (exercise plus simvastatin n= 18 exercise only n= 19) showed that simvastatin attenuates increases in cardiorespiratory fitness and skeletal muscle mitochondrial content when combined with exercise training in patients at risk of the metabolic syndrome [51]. The short-term administration of high-dose atorvastatin did not result in altered muscle function despite mild increases in creatine kinase levels [52]. 

Poortmans, J.R., H. Auquier, V. Renaut, A. Durussel, M. Saugy, and G.R. Brisson, Effect of short-term creatine supplementation on renal responses in men. Eur J Appl Physiol Occup Physiol, 76 566-567, 1997. 

Volek, J.S., S.A. Mazzetti, W.B. Farquhar, B.R. Barnes, A.L. Gomez, and W.J. Kraemer, Physiological responses to short-term exercise in the heat after creatine loading. Med Sci Sports Exerc, 33 1101-1108, 2001. 

Cardiac enzyme elevation (creatine kinase-MB, cardiac troponin) may occur on average in 20% to 30% of patients after PCI and is associated with adverse clinical outcomes in the short- and long-term (64), Magnetic resonance imaging... 

There is little information on the short- or long-term side effects on the safety of creatine supplementation. However, there have been reports of some athletes suffering side effects with the alleged overdosing of creatine (e.g, the natural production of creatine being curtailed in the athlete s body). The European Commission s Scientific Committee on Food (September 7, 2000) has concluded that high doses of creatine supplementation should be avoided (i.e., > 3 grams per day). 

Double-blind placebo-controlled studies of oral supplementation of creatine in human subjects have shown increased performance during short duration, strenuous, high-intensity exercise. Such activities require that ATP be replenished rapidly from phosphocreatine stores during anaerobic metabolism. These studies usually consisted of ingestion of 20 g of creatine per day for 5 days followed by a maintenance dose of 5-10 g/day. Studies on creatine as an ergogenic aid have not been uniformly positive some have shown no beneficial effect and still others have been equivocal and indicated that creatine supplementation did not enhance athletic activities. The safety issues of long-term creatine supplementation on kidney, liver, nerve, muscle, and other tissues are not known. 

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