Creatine is a nitrogenous amine. Normal daily dietary intake of creatine from an omnivorous diet is about 1 gram. Dietary sources of creatine include meat, fish, and other animal products, but it may also be formed endogenously in the liver, kidney, and pancreas from the amino acids glycine, arginine, and methionine. One-half kg of fresh, uncooked steak contains about 2 grams of creatine. Creatine has become an extremely popular nutritional ergogenic among athletes. In 1998, about $200 million was spent on creatine monohydrate (the most studied form of creatine). Of the approximately 300 studies that have evaluated the potential performance-enhancing (ergogenic) value of creatine monohydrate supplementation, about 70% of these studies report statistically significant results while remaining studies generally report non-significant gains in performance.1 However, studies that have reported no significant benefit of creatine supplementation often have low statistical power, have evaluated performance tests with large test-to-test variability, and/or have not incorporated appropriate experimental controls.1 Thus, the predominance of research indicates that creatine monohydrate supplementation represents an effective nutritional method to enhance athletic performance, especially muscle size and strength responses to resistance training.16 Creatine supplementation is not banned by the International Olympic Committee and, with the exception of a small increase in body mass (~1 kg) over the initial 3-6 days, does not appear to have any adverse side effects.2 Limited scientific data are available for more prolonged use but considering the huge numbers of athletes using creatine over the past 10+ years and the absence of reported problems, it is very likely that the purported long-term adverse outcomes are being overestimated.2 In fact, creatine supplementation has been, and continues to be, investigated as a possible therapeutic approach for the treatment of muscular, neurological and neuromuscular diseases (arthritis, congestive heart failure, disuse atrophy, gyrate atrophy, McArdles disease, Huntington`s disease, miscellaneous neuromuscular diseases, mitochondrial diseases, muscular dystrophy, neuroprotection, etc.). Creatine Storage in the Body About 120 grams of creatine is found in a 70 kilogram male, 95% in the skeletal muscle.3 Total creatine exists in the muscle as both free creatine and phosphocreatine. About 60% of the total creatine is phosphocreatine, and the remainder is free creatine.3 For creatine supplementation to be effective, it must increase the amount of total creatine or phosphocreatine within the muscle, and these increased stores must help rapidly replenish phosphocreatine and adenosine triphopshate (ATP) during exercise. The most popular way to use supplemental creatine is to load creatine by taking 5 grams of creatine monohydrate four times per day for 5 to 7 days. This protocol rapidly increases muscle creatine levels. Once muscle creatine stores are saturated, you only need to take about 5 grams of creatine monohydrate per day in order to maintain elevated creatine stores. Creatine, Carbs and Protein Dr. Green and colleagues reported that creatine ingested in combination with high-glycemic carbs substantially increased muscle creatine accumulation compared with the ingestion of creatine alone.5 In addition, this approach reduced the interindividual variability in the magnitude of muscle creatine accumulation, such that all subjects demonstrated significant increase in muscle total creatine. In other worlds, there were no creatine "non-responders" when creatine was ingested with high-glycemic carbs. It is likely that the stimulatory effect of high-glycemic carbs on muscle creatine accumulation was due to insulin-enhancing muscle uptake. However, creatine supplements would need to be ingested with very large quantities of high-glycemic carbs to achieve an insulin-mediated stimulation of muscle creatine transport. This is a very bad idea, unless you want to look like the Michelin Man. Fortunately, the ingestion of proteins in combination with carbs can result in a greater increase in blood insulin concentrations than would be expected from the sum of their individual responses.7 So, the aim of the study by Dr. Steenge and co-workers was to examine whether the ingestion of creatine in combination with a solution containing about 50 grams of protein and about 50 grams of high-glycemic carbs could increase blood insulin concentration to a level similar to that observed after the ingestion of about 100 grams of high-glycemic carbs.8 The second aim was to determine whether this would facilitate creatine retention toward that reported with large quantities of simple carbohydrates. The results of this study indicate that the ingestion of creatine, in conjunction with about 50 g protein and about 50 g of carbohydrates, is as effective in stimulating insulin release and whole body creatine retention as ingesting creatine in combination with almost 100 grams of carbohydrates. In summary, there is absolutely no reason to use those sugar-loaded creatine transport formulations. The suggestion that one should take in some 75 grams of sugar with each creatine dose is simply ridiculous. Rather, I suggest that you mix your daily (maintenance) creatine dose in a post-exercise protein-carbohydrate drink. If you feel you need another dose (e.g., 5 grams), take it with carbohydrate-containing breakfast. By the way, a protein hydrolysate has much stronger insulin boosting effect than intact proteins19, so a protein hydrolysate-carbs-creatine mixture may be the best way to maximize creatine transport into skeletal muscle. Creatine and D-Pinitol D-pinitol is a plant extract that has been reported to possess insulin-like properties. Thus, the purpose of a recent study by Dr. Greenwood and co-workers was to examine whether co-ingestion of D-pinitol with creatine affects whole body creatine retention.9 Results suggested that ingesting creatine with low doses of D-pinitol (2 x 0.5 grams per day) may augment whole body creatine retention in a similar manner as has been reported with co-ingestion of high levels of carbs or carbs plus protein. However, ingestion of a higher dose of D-pinitol (4 x 0.5 grams per day) did not enhance retention. Clearly, more research is needed before conclusions can be drawn. Effervescent Creatine Effervescent creatine products have been marketed as a more optimal means of ingesting creatine because they theoretically enhance the suspension and solubility of the creatine in liquid, optimize pH levels to prevent degradation of creatine to creatinine, and reduce purported gastrointestinal problems that may interfere with creatine transport in the gut. Dr. Greenwood and colleagues reported that effervescent creatine supplementation (creatine citrate + dextrose + sodium + potassium) is not more effective than ingesting creatine monohydrate alone.10 Thus, there is no reason to waste money on effervescent creatine. Creatine Serum The peddlers of creatine serum have claimed that roughly 90% of ingested creatine monohydrate will be hydrolyzed to creatinine by stomach acid, leaving about 10% to enter the blood stream and be taken up by muscle cells. True, the rate of formation of the degradation product, creatinine, is increased in the presence of acid and therefore accelerated degradation is possible in the lower pH of the stomach. However,creatine degradation to creatine occurs at its maximal rate at pH 3-4.15 The degradation half-lives for the conversion of creatine to creatinine at pH values 1.4, 3.7 and 6.8 are 55, 7.5 and 40.5 days, respectively.15 At these rates, less than 0.1 g of a 5 g dose would be lost in 1 hour. So, conversion to creatinine in the gastrointestinal tract is minimal regardless of transit time. Dr. Kreider and colleagues examined whether creatine serum supplementation has any effect on muscle adenosine triphosphate (ATP) or creatine levels.13 Results revealed that creatine monohydrate significantly increased muscle creatine content while no significant differences were observed among liquid placebo or creatine serum in pre- and post-ATP or creatine levels. These findings indicated that creatine serum has zero effect on muscle ATP or creatine stores even when taken at eight times the recommended dosage for 5 days. More recently, Dr. Gill and co-workers reported that creatine serum did not affect sprint cycling performance.17 In summary, don't waste your money on creatine serum. Creatine and Caffeine Caffeine is the most popular performance-enhancing substance known to mankind. It improves performance during prolonged, exhaustive exercise. To a lesser degree it also enhances short-term, high-intensity athletic performance.11 It is relatively safe and has no known negative performance effects, nor does it cause significant dehydration or electrolyte imbalance during exercise.11 Dr. Vandenberghe and coworkers compared the effects of creatine supplementation with creatine supplementation in combination with caffeine on muscle phosphocreatine level and performance in healthy male volunteers.12 Creatine and creatine + caffeine increased muscle phosphocreatine concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% by creatine but was not changed by creatine + caffeine. The authors concluded that creatine supplementation elevates muscle phosphocreatine concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, was completely eliminated by caffeine intake. Additional research is needed to confirm these preliminary findings. Creatine + Beta-Alanine = Dynamic Duo? The latest addition to our ergogenic arsenal is B-alanine (beta-alanine), a nonessential amino acid that's found in many foods we eat. Preliminary reports have suggest that beta-alanine supplementation can increase muscle carnosine levels and exercise performance. A recent study by Jeff Hoffman and colleagues examined the effects of creatine and creatine plus beta-alanine supplementation on strength, power, body composition, and hormonal changes during a 10-week resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (10.5 grams of dextrose per day), creatine monohydrate (10.5 grams per day), or creatine monohydrate plus B-alanine (10.5 and 3.2 grams per day, respectively) group. The results indicated that the addition of beta-alanine enhances training volume more so than creatine alone and that B-alanine supplementation has the greatest effect on lean tissue accruement and body fat composition. However, it is unclear whether this study was really placebo controlled. According to the authors, "The supplement and placebo were in powdered form and mixed with 8 to 10 ounces of water". Dextrose is very sweet, where as creatine and beta-alanine are not. Thus, it is possible that the subjects who took placebo were aware of it. Whatever the case, beta-alanine supplementation certainly holds some promise. Creatine Ethyl Ester (CEE) CEE is creatine with an ester attached. It has been suggested that CEE more efficiently permeates the cell wall, compared to regular creatine. However, there is no scientific evidence supporting this notion. In fact, there are absolutely no studies examining the effects of CEE supplementation on exercise performance, body composition or general health. Thus, efficacy and safety of CEE are unknown, so its use cannot be recommended. Bottom Line Creatine monohydrate is the most studied form of creatine. Numerous studies have demonstrated that creatine monohydrate supplementation represents an effective and safe nutritional method to enhance athletic performance, especially muscle size and strength responses to resistance training. ProSource Creatine contains only 100% pure premium grade German creatine monohydrate (CreaPureTM). Independent lab tests have consistently showed that CreaPure is the most pure creatine available. Chinese creatine has contaminants and large particle size, which may result in cramping and poor absorption. Another ProSource product containing CreaPure is SynthaTrex. This advanced formula also provides a proprietary creatine transport complex as well as arginine-AKG, a vasodilator that expands blood vessels, increasing nutrient transport into muscle cells.
About Anssi Manninen Anssi Manninen holds an M.H.S. in sports medicine from the University of Kuopio Medical School. His numerous cutting-edge articles in Muscular Development firmly established his reputation as a leading authority on hard-core sports nutrition. Anssi's articles have also been published in scientific journals, including The British Journal of Sports Medicine, The Journal of International Society of Sports Nutrition, Nutrition & Metabolism, and Journal of Sports Science and Medicine. Anssi is also an Associate Editor for Nutrition & Metabolism, a leading scientific journal in the area of nutritional biochemistry.
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