Creatine

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Latest Edit: Hector 2014-03-17 (EDT)

See Also Food Supplements

Creatine is a non-protein amino acid made up of L-arginine, glycine, and L-methionine. It is synthesized in the liver, kidney, and pancreas and then transported to the skeletal muscles, heart, brain, and other tissues. Creatine is metabolized into phosphocreatine or creatine phosphate and acts as a major energy store in the body. When supplemented, creatine generates energy during anaerobic exercise and may also be neuroprotective and cardioprotective. [1]

Food Sources

Creatine is naturally occurring in meat and fish, and it is also made by the human body in the liver, kidneys, and pancreas.


Uses

The following are the primary uses for creatine. [1]

Article Creatine: Clinical applications, IHP, October 2010
  • Athletic Performance Enhancement: The benefits of creatine in the realm of athletic performance enhancement is limited to high intensity, short-term activities in elite athletes, but the evidence seems to be mixed. Recall that creatine is converted to phosphocreatine which acts as a major energy store. During high-intensity activities, this store is tapped into and phosphocreatine becomes the limiting factor in skeletal muscle performance. One study author concluded that an ergogenic (increase in body mass) is achieved with creatine supplementation, at least in the laboratory setting, during repeated stationary cycling sprints. He also reported an ergogenic effect in weightlifters but not in runners or swimmers. Weight gain often accompanies creatine supplementation and it is debated whether this is truly muscle mass increase or water retention. This weight gain could account for the lack of benefit seen with runners and swimmers.
  • Muscular Dystrophy: In one preliminary study, supplementation with creatine showed increases in hand grip and ankle and knee strength. More research is needed.
  • Amyotrophic Lateral Sclerosis: A study done in mice shows promising results for the use of creatine in ALS. Creatine supplementation prolonged life, improved motor-performance tests, and contributed to histological changes consistent with neuron protection in the substantia nigra. These results have stimulated interest in the possibility of using creatine in the treatment of Parkinson's disease. More research is needed in this area.
  • Improvement of Muscle Function in Other Conditions: Supplementation with creatine has shown some improvement in terms of skeletal muscle function in both individuals with congestive heart failure and genetic gyrate atrophy. The effects were small and the research is still preliminary.

Prescribing Considerations

The typical form of creatine available is a creatine monohydrate powder. It's also available as capsules, effervescent tablets and powder, and wafers [1]

  • Adults: An example of a typical loading dose in exercise performance: Take 5g of creatine monohydrate, 4 times daily (20s total daily) for 2 to 5 days.
  • Maintenance dose in exercise performance: Take 2g daily.
  • Children: Creatine supplementation should be avoided in children and adolescents.
  • Pregnancy and Breastfeeding: Not advised
  • Creatine may be better absorbed when you take it with carbohydrate foods, such as fruits, fruit juices, and starches.

Safety

The safety precautions include:

  • Side-effects are rare, but may include: gastrointestinal concerns such as nausea, diarrhea, and indigestion; muscle cramping and strains; weight gain from water retention; elevated serum creatinine (a metabolite of creatine and a marker of kidney function); some anecdotal reports of adverse effects include rash, dyspnea, vomiting, diarrhea, nervousness, anxiety, migraine, fatigue, polymyositis, myopathy, seizures, and atrial fibrillation
  • Pregnancy Breastfeeding
  • Creatine supplementation should be avoided in this population.
  • Contraindications
  • renal failure and renal disorders such as nephrotic syndrome and in diabetics with renal dysfunction.
  • Drug Interactions
  • There are no known drug or herb interactions. [1]
  • Nutrient Interactions[1]
  • Caffeine - Caffeine appears to interfere with any beneficial effects of creatine supplementation.

References

  1. 1.0 1.1 1.2 1.3 1.4 Hendler Sheldon S, Rorvik David (Editors) (2001) PDR for Nutritional Supplements, Medical Economics Company Inc. Cite error: Invalid <ref> tag; name "hendler" defined multiple times with different content Cite error: Invalid <ref> tag; name "hendler" defined multiple times with different content Cite error: Invalid <ref> tag; name "hendler" defined multiple times with different content