Pyne-Geithman et al. This type of mutation generally results in virtually complete creatine depletion in the brain, although observed musculoskeletal and cardiac function remain as normal. A muscle biopsy was excised from the patient following surgery for scoliosis and compared to three other archived samples to serve as a control. It was concluded that muscle was not affected by the CreaT mutation since no abnormalities were seen in creatine concentration, muscle histology, and electron transport chain activity.
The authors suggested that there are different methods, as well as several factors, that allow creatine uptake in the muscle when compared to the brain. Creatine synthesis was also ruled out since synthesis has not been observed in skeletal muscle in humans nor in animal models. This research clarifies that muscle and brain respond differently to creatine transport. Since meat is the primary dietary source for creatine, the examination of vegetarians may provide a unique aspect to creatine metabolism research.
Watt et al. Results indicated that vegetarians had a lower initial total creatine concentration, and during supplementation, both groups significantly increased total creatine levels.
However, vegetarians' total creatine content increased to a greater extent. Therefore, during a creatine loading protocol, vegetarians appear to possess a greater ability to take up creatine when compared to their omnivorous counterparts. Previous research has concluded that there is no gender difference in the total creatine content in muscle, either before or after supplementation. Although this suggests that CreaT activity is unlikely to differ between genders, no research has directly investigated this.
Two groups, separated by gender, had a muscle biopsy taken, which was then analyzed for CreaT mRNA, CreaT protein, and total creatine content. The results failed to show any differences between genders in neither total creatine content nor CreaT protein quantity, with CreaT protein expression greatest in type I fibers than in type II muscle fibers.
Lastly, results concluded that there was an inverse relationship between total creatine content and CreaT protein content for females. It was noted that this relationship was also very close to being significant for males as well; after an outlier was removed, both genders proved statistically significant. Therefore, as total creatine content increases, the creatine transporter content decreases, and vice versa.
This research exhibits the same indirect relationship that has been observed in previous animal models. The authors suggest that muscle fiber type needs to be taken into account for future research measuring CreaT expression, since type I fibers tend to have a greater abundance of CreaT protein. Previous animal research has repeatedly shown a down regulation in CreaT expression following long-term creatine supplementation. It is argued that since the animal doses of creatine were much higher when equated to humans, down-regulation of the CreaT may be very slight or nonexistent when applied to a typical moderate dosing regimen in human individuals.
Additionally, no alteration in CreaT protein content was apparent with either creatine supplementation or exercise training. CreaT mRNA was not affected following acute creatine loading.
In conclusion, creatine supplementation with a simultaneous resistance training protocol effectively raised the intracellular creatine content and did not result in a decrease in CreaT protein or CreaT mRNA. Most studies have reported an increase in intramuscular creatine levels with supplementation; however, variability does exist. This poses the possible scenario of "responders" versus "nonresponders" to creatine supplementation. It is hypothesized that much of this variability lies within the regulation and activity of the creatine transporter.
Unfortunately, most of the limited creatine supplementation research conducted investigating the expression of CreaT has been through animal models, as previously noted. Recently, Syrotuik and Bell [ 25 ] conducted a descriptive profile of individuals portraying Greenhaff's classification of "responder" and "non-responder" characteristics. Results of this study concluded that the responders generally: 1 possessed a lower initial quantity of intramuscular creatine and were able to absorb and take up a greater amount through supplementation; 2 had a greater percentage of type II fibers; 3 had a greater fiber cross sectional area; and 4 possessed more fat-free mass.
This data suggests that an individual's biological profile may partially determine the efficacy of a creatine supplementation protocol. A significant amount of literature has developed in regards to the most effective means to enhance creatine uptake. Adding creatine with a carbohydrate source has been observed to enhance uptake, primarily through the effect of an insulin response [ 4 , 26 ].
Additionally, some research in cell culture has indicated that combining creatine and sodium may additionally enhance creatine uptake via the manipulation of increasing the gradient in which the CreaT functions [ 27 ]. The current literature is very preliminary in relation to examining how creatine supplementation affects CreaT expression while concomitantly following a resistance training protocol.
National Center for Biotechnology Information , U. J Int Soc Sports Nutr. Published online Jun Author information Article notes Copyright and License information Disclaimer. Corresponding author. Ryan D Schoch: ude. Received Feb 28; Accepted Jun It should be noted that the International Olympic Committee IOC has considered many arguments against its supplementation and stated that there was no need for its ban. The IOC stated that supplementation should be treated as any food because it can easily be found in meat and fish.
Further, creatine supplementation is not banned by any organization as of a review article in the Journal of the International Society of Sports Nutrition, but the National Collegiate Athletic Association NCAA does prohibit its distribution, along with other muscle-building products, to its athletes but does not ban its use independently. As a final note, there has been no research indicating any short term or long term detriment associated with creatine supplementation.
Both short and long term studies have found creatine supplementation to be safe when following recommended guidelines. Creatine has been found to be a legal and safe dietary supplement that aids in athletic performance and strength development and its effects are maximized when taken in conjunction with resistance training.
Food and Drug Administration. Stout, J. Overview of Creatine Metabolism. Essential of Creatine in Sports and Health. Humana Press: Totowa, N. Rowbottom, M. Drugs in sport: Creatine given all-clear by IOC. Independent [online], December 14, East, D. Biochemical Pathways of Creatine and Creatine Phosphate. Honors Thesis.
University of Tennessee, Knoxville, TN, Clark, J. Creatine and phosphocreatine: A review of their use in exercise and sport. J Athl Train , 32, and references therein. Halkerston IDK. Biochemistry, 2nd ed. New York: John Wiley and Sons; Oral creatine supplementation and upper extremity anaerobic response in females. Int J Sport Nutr Metab ; — Glycogen, glycolytic intermediates and high-energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest: methods and variance of values.
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Biochem Soc Trans ; S. By , All American Pharmaceutical was in full production of creatine monohydrate at our plant in Billings, Montana. The next significant shift in creatine technology took place on June 6, , when I introduced Kre-Alkalyn pH-correct creatine to the marketplace.
Search Advertise. Jeff Golini Ph. The History of Creatine. Jeff Golini.
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