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hc8meifmdc|20005939267D|healthm_live|health_library|health_library_details|0xfdffd5d1080000003902000001000100
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Creatine is a naturally occurring amino acid (protein building block) that's found in meat and fish, and also made by the human body in the liver, kidneys, and pancreas. It is converted into creatine phosphate or phosphocreatine and stored in the muscles, where it is used for energy. During high-intensity, short-duration exercise, such as lifting weights or sprinting, phosphocreatine is converted into ATP, a major source of energy within the human body.
Creatine supplements are popular among body builders and competitive athletes. It is estimated that Americans spend roughly $14 million per year on creatine supplements. The attraction of creatine is that it may increase lean muscle mass and enhance athletic performance, particularly during high-intensity, short-duration sports (like high jumping and weight lifting).
Every person does not seem to respond the same way to creatine supplements. For example, people who tend to have naturally high stores of creatine in their muscles don't get an energy-boosting effect from extra creatine. Preliminary clinical studies also suggest that creatine's ability to increase muscle mass and strength may help combat muscle weakness associated with illnesses such as heart failure and muscular dystrophy.
What is Creatine ?
Creatine is a naturally occurring substance and key to building powerful skeletal muscle-huge biceps, defined “diamond†triceps, big pecs and more. Creatine is one of the most widely used sports supplements on the market today. Primary use is in strength and bulk-building exercises that improve performance for high-intensity sports, maximize your workouts, and give you an edge in anaerobic athletic competitions.
Introduced to the athletic arena in 1993, creatine has enjoyed one long, smooth and nearly uninterrupted surge in use. Interest first spiked in the months following the 1992 Summer Olympics. During those games a number of athletes that blasted beyond competitors to win medals reported later that they had used creatine supplements to augment their training regimens. Since creatine is natural there are no restrictions on its use among athletes.
Creatine is a naturally occurring amino acid that is generated in the human body, as well as ingested as part of a natural meat-eating diet. Your liver and kidneys produce small amounts of creatine and if you eat meat, particularly game, and fish like tuna and herring, you gain more natural creatine that in turn becomes available to your skeletal muscles, the biceps, triceps, pecs and all other muscles that form the structure of your body. But if you're looking to pack on muscle bulk fast then these natural sources are not enough.
In your skeletal muscles, where you build bulk and generate the energy for movement, creatine participates in the complex muscle contraction process to maximize muscle energy. Adenosine Triphosphate, abbreviated to ATP, is a key fuel for muscle contraction, the repetition exercises you perform when bodybuilding. The more ATP you make available to your muscles the more energy created to power bodybuilding and boost performance in bursty sports, like sprinting, rowing, bodybuilding. Normal levels of ATP allow you only a few seconds of high-intensity energy.
Creatine fuels ATP development, which means:
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Sustained high intensity and power workouts |
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More energy for muscle contraction |
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Vastly improved power and muscle size |
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You workout longer, stronger and get to see the results in the mirror. | |
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Where it is found
About half of the creatine in our bodies is made from other amino acids in the liver, kidney and pancreas, while the other half comes from foods we eat. Wild game is considered to be the richest source of creatine, but lean red meat and fish (particularly herring, salmon, and tuna) are also good sources.
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Benefits / uses
Athletic performance
Creatine supplements improve strength and lean muscle mass during high-intensity, short-duration exercises (such as weight lifting). In these studies, the positive results were seen mainly in young people (roughly 20 years of age). Creatine does not seem to improve performance in exercises that requires endurance (like running) or in exercise that isn't repeated.
Although creatine is not banned by the National Collegiate Athletic Association (NCAA) or the International Olympic Committee, using it for athletic performance is controversial. The NCAA prohibits member schools from giving creatine and other muscle building supplements to their athletes, although it doesn't ban athletes from using it. The French Agency of Medical Security for Food (AFSSA) asserts that the use of creatine supplements is "against the spirit of sportsmanship and fair competition."
Creatine appears to be generally safe, although when it is taken at high doses there is the potential for serious side effects such as kidney damage and the risk of inhibiting the body's natural formation of creatine.
Heart disease
A preliminary clinical study suggests that creatine supplements may help lower levels of triglycerides (fats in the blood) in men and women with abnormally high concentrations of triglycerides.
In a few clinical studies of people with congestive heart failure, those who took creatine (in addition to standard medical care) saw improvement in the amount of exercise they could do before becoming fatigued, compared to those who took placebo. Getting tired easily is one of the major symptoms of congestive heart failure. One clinical study of 20 people with congestive heart failure found that short-term creatine supplementation in addition to standard medication lead to an increase in body weight and an improvement of muscle strength.
Creatine has also been reported to help lower levels of homocysteine. Homocysteine is a marker of potential heart disease, including heart attack and stroke.
Chronic Obstructive Pulmonary Disease (COPD)
In one double-blind study, people with COPD who took creatine increased muscle mass, muscle strength and endurance, and improved their health status compared with those who took placebo. They did not increase their exercise capacity.
Muscular dystrophy
People who have muscular dystrophy may have less creatine in their muscle cells, which may contribute to muscle weakness. One study found that taking creatine resulted in a small improvement in muscle strength.
Parkinson's disease
People with Parkinson's disease have decreased muscular fitness including decreased muscle mass, muscle strength, and increased fatigue. A small clinical study found that giving creatine to people with Parkinson's disease improved their exercise ability and endurance. In another clinical study, creatinine supplementation improved patients' moods and led to a smaller dose increase of drug therapy.
Doses
Adult
BY MOUTH:
For improving physical performance, several dosing regimens have been tried:
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Creatine is typically loaded with 20 grams per day (or 0.3 grams per kg) for 5 days followed by a maintenance dose of 2 or more grams (0.03 grams per kg) daily, Although 5 day loading is typical, 2 days of loading has also been used. |
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A loading dose of 9 grams per day for 6 days has also been used. Some sources suggest that, instead of acutely loading, similar results can be obtained with 3 grams per day for 28 days. |
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For heart failure: 20 grams per day for 5-10 days. |
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For Parkinson's disease: |
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10 grams/day. |
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A loading dose of creatine 20 grams/day for 6 days followed by 2 grams/day for 6 months, and then 4 grams daily for 18 months has also been used. | |
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For improving resistance training in people with Parkinson's disease: a loading dose of 20 grams/day for 5 days, followed by 5 grams/day. |
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For gyrate atrophy: 1.5 grams per day. |
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For muscular dystrophies: 10 grams per day has been used by adults and 5 grams per day has been used by children. |
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For McArdle's disease: 150 mg / kg daily for 5 days and then continue with 60 mg / kg / day. | |
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Possible Side effects / Precautions / Possible Interactions:
Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable health care provider.
Side effects of creatine include weight gain, muscle cramps, muscle strains and pulls, stomach upset, diarrhea, dizziness, high blood pressure, liver dysfunction, and kidney damage. Most studies have found no significant side effects at the doses used for up to six months.
Rhabdomyolysis (breakdown of skeletal muscle tissue) and acute kidney failure was reported in one case involving an athlete taking more than 10 grams daily of creatine for 6 weeks. People with kidney disease, high blood pressure, or liver disease should avoid creatine.
Taking creatine supplements may prevent the body from making its own natural stores, although the long-term effects are not known. The Food & Drug Administration recommends talking to your doctor before starting to take creatine.
There have been reports of contaminated creatine supplements. Be sure to buy products made by established companies with good reputations.
Possible Interactions:
If you are currently being treated with any of the following medications, you should not use creatine without first talking to your health care provider.
Non-steroidal anti-inflammatory drugs (NSAIDs) -- Creatine may increase the risk of damage if taken with these pain relievers, such as ibuprofen (Motrin, Advil) or naproxen (Aleve).
Caffeine -- Caffeine may inhibit the body's ability to use creatine. Taking creatine and caffeine may increase risk of dehydration. Using creatine, caffeine, and ephedra (a substance that has been banned in the U.S. but that was used in sports supplements) may increase the risk of stroke.
Diuretics (water pills) -- Taking creatine with diuretics may increase the risk of dehydration and kidney damage.
Cimetidine (Tagamet) -- Taking creatine while taking Tagamet may increase the risk of kidney damage.
Probenicid -- Taking creatine while taking probenecid (a drug used to treat gout) may increase the risk of kidney damage.
Research studies / References
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Cannan, R. K.; Shore, A. (1928). "The Creatine-Creatinine Equilibrium. The Apparent Dissociation Constants of Creatine and Creatinine.". Biochem. J. 22 (4): 920-29. PMC 1252207. PMID 16744118. http://www.biochemj.org/bj/022/0920/0220920.pdf. Retrieved 2010-10-29. |
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"Creatine". MedLine Plus Supplements. U.S. National Library of Medicine. 2010-07-20. http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-creatine.html. Retrieved 2010-08-16. |
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"Creatine". Beth Israel Deaconess Medical Center. |
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http://www.bidmc.org/YourHealth/ConditionsAZ.aspx?ChunkID=21706. Retrieved 2010-08-23. |
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Burke DG, Chilibeck PD, Parise G, Candow DG, Mahoney D, Tarnopolsky M (2003). "Effect of creatine and weight training on muscle creatine and performance in vegetarians". Medicine and science in sports and exercise 35 (11): 1946-55. doi:10.1249/01.MSS.0000093614.17517.79. PMID 14600563. |
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"Creatine". Beth Israel Deaconess Medical Center. |
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http://www.bidmc.org/YourHealth/ConditionsAZ.aspx?ChunkID=21706. Retrieved 2010-08-23. |
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a b "ETH ETH E-Collection: Methylglyoxal, creatine and mitochondrial micro-compartments - ETH E-Collection". E-collection.ethbib.ethz.ch. 2008-04-19. doi:10.3929/ethz-a-004636659.. http://e-collection.ethbib.ethz.ch/ecol-pool/diss/fulltext/eth15180.pdf. Retrieved 2010-08-16. |
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"L-Arginine:Glycine Amidinotransferase". Ncbi.nlm.nih.gov. |
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http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=602360. Retrieved 2010-08-16. |
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"Intracellular compartmentation, structure and function of creatine kinase isoenzymes in tissues with high and fluctuating energy demands: the 'phosphocreatine circuit' for cellular energy homeostasis". |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1130636/pdf/biochemj00144-0029.pdf. Retrieved 2011-03-01. |
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"Intracellular compartmentation, structure and function of creatine kinase isoenzymes in tissues with high and fluctuating energy demands: the 'phosphocreatine circuit' for cellular energy homeostasis". |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1130636/pdf/biochemj00144-0029.pdf. Retrieved 2011-03-01. |
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"The effects of creatine ethyl ester supplementation combined with heavy resistance training on body composition, muscle performance, and serum and muscle creatine levels". http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649889/. Retrieved 2011-3-11. |
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doi:10.1007/s00726-011-0877-3. |
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"Creatine: is it really safe for long-term use?". Pponline.co.uk. http://www.pponline.co.uk/encyc/creatine.htm. Retrieved 2010-08-16. |
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a b "Creatine: Safety". MayoClinic.com. |
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http://www.mayoclinic.com/health/creatine/NS_patient-creatine/DSECTION=safety. Retrieved 2010-08-16. |
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Lopez RM, Casa DJ, McDermott BP, Ganio MS, Armstrong LE, Maresh CM (2009). "Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses". Journal of Athletic Training 44 (2): 215-23. doi:10.4085/1062-6050-44.2.215. PMC 2657025. PMID 19295968. |
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Dalbo VJ, Roberts MD, Stout JR, Kerksick CM (July 2008). "Putting to rest the myth of creatine supplementation leading to muscle cramps and dehydration". British Journal of Sports Medicine 42 (7): 567-73. doi:10.1136/bjsm.2007.042473. PMID 18184753. |
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Poortmans JR, Francaux M (September 2000). "Adverse effects of creatine supplementation: fact or fiction?". Sports Medicine 30 (3): 155-70. doi:10.2165/00007256-200030030-00002. PMID 10999421. |
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Francaux M, Poortmans JR (December 2006). "Side effects of creatine supplementation in athletes". International Journal of Sports Physiology and Performance 1 (4): 311-23. PMID 19124889. |
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Bizzarini E, De Angelis L (December 2004). "Is the use of oral creatine supplementation safe?". The Journal of Sports Medicine and Physical Fitness 44 (4): 411-6. PMID 15758854. |
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Bemben MG, Lamont HS (2005). "Creatine supplementation and exercise performance: recent findings". Sports Medicine 35 (2): 107-25. PMID 15707376. |
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Kreider RB (February 2003). "Effects of creatine supplementation on performance and training adaptations". Molecular and Cellular Biochemistry 244 (1-2): 89-94. doi:10.1023/A:1022465203458. PMID 12701815. |
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http://www.kluweronline.com/art.pdf?issn=0300-8177&volume=244&page=89. |
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Kamber M, Koster M, Kreis R, Walker G, Boesch C, Hoppeler H. Creatine supplementation--part I: performance, clinical chemistry, and muscle volume. Med. Sci. Sports Exer. 31: 1763-1769, 1999. |
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Deldicque L, Décombaz J, Zbinden Foncea H, Vuichoud J, Poortmans JR, Francaux M. Kinetics of creatine ingested as a food ingredient. Eur. J. Appl. Physiol. 102: 133-143, 2008. |
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R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 366-368. |
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Hülsemann J, Manz F, Wember T, Schoch G (1987). "[Administration of creatine and creatinine with breast milk and infant milk preparations]" (in German). Klinische Pädiatrie 199 (4): 292-5. doi:10.1055/s-2008-1026805. PMID 3657037. |
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Wallimann, Theo; Tokarska-Schlattner, Malgorzata; Schlattner, Uwe (2011-05-01). "The creatine kinase system and pleiotropic effects of creatine" (in English). Amino Acids (Springer Wien) 40 (5): 1271-1296. doi:10.1007/s00726-011-0877-3. ISSN 0939-4451. http://dx.doi.org/10.1007/s00726-011-0877-3. Retrieved May 8 2011. |
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Tarnopolsky M, Martin J (March 1999). "Creatine monohydrate increases strength in patients with neuromuscular disease". Neurology 52 (4): 854-7. PMID 10078740. http://www.neurology.org/cgi/pmidlookup?view=long&pmid=10078740. |
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Klivenyi P, Ferrante RJ, Matthews RT, et al. (March 1999). "Neuroprotective effects of creatine in a transgenic animal model of amyotrophic lateral sclerosis". Nature Medicine 5 (3): 347-50. doi:10.1038/6568. PMID 10086395. |
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Andreassen OA, Dedeoglu A, Ferrante RJ, et al. (June 2001). "Creatine increase survival and delays motor symptoms in a transgenic animal model of Huntington's disease". Neurobiology of Disease 8 (3): 479-91. doi:10.1006/nbdi.2001.0406. PMID 11447996. |
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Rae C, Digney AL, McEwan SR, Bates TC (October 2003). "Oral creatine monohydrate supplementation improves brain performance: a double-blind, placebo-controlled, cross-over trial". Proceedings. Biological Sciences / the Royal Society 270 (1529): 2147-50. doi:10.1098/rspb.2003.2492. PMC 1691485. PMID 14561278. |
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McMorris T, Mielcarz G, Harris RC, Swain JP, Howard A (September 2007). "Creatine supplementation and cognitive performance in elderly individuals". Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition 14 (5): 517-28. doi:10.1080/13825580600788100. PMID 17828627. |
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Rawson ES, Lieberman HR, Walsh TM, Zuber SM, Harhart JM, Matthews TC (September 2008). "Creatine supplementation does not improve cognitive function in young adults". Physiology & Behavior 95 (1-2): 130-4. doi:10.1016/j.physbeh.2008.05.009. PMID 18579168 | |
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