The remaining amount of creatine is synthesized primarily in the liver and kidneys from arginine and glycine by the enzyme arginine:glycine amidinotransferase (AGAT) to guanidinoacetate (GAA), which is then methylated by guanidinoacetate N-methyltransferase (GAMT) using S-adenosyl methionine to form creatine (see Fig. For example, a pound of uncooked beef and salmon provides about 1–2 g of creatine. About half of the daily need for creatine is obtained from the diet. Therefore, the body needs to replenish about 1–3 g of creatine per day to maintain normal (unsupplemented) creatine stores depending on muscle mass. About 1–2% of intramuscular creatine is degraded into creatinine (metabolic byproduct) and excreted in the urine. However, the upper limit of creatine storage appears to be about 160 mmol/kg of dry muscle mass in most individuals. The total creatine pool (PCr + Cr) in the muscle averages about 120 mmol/kg of dry muscle mass for a 70 kg individual.
STAND O FOOD 3 REVIEW FREE
About two thirds of intramuscular creatine is phosphocreatine (PCr) with the remaining being free creatine. The majority of creatine is found in skeletal muscle (~95%) with small amounts also found in the brain and testes (~5%).
STAND O FOOD 3 REVIEW UPDATE
The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN) related to creatine supplementation.Ĭreatine, a member of the guanidine phosphagen family, is a naturally occurring non-protein amino acid compound found primarily in red meat and seafood. A number of clinical applications of creatine supplementation have also been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson’s, Huntington’s disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. Research has indicated that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations, can improve exercise performance, and/or improve training adaptations. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).Ĭreatine is one of the most popular nutritional ergogenic aids for athletes. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly.
Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson’s, Huntington’s disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection.
Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. Creatine is one of the most popular nutritional ergogenic aids for athletes.
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