There is a lot of controversy on nutritional supplements and performance/health claims that go along with them. Many claims come and go without a lot of hassle, but none has generated the commotion of the interest or debate surrounding creatine (Cr). Many people believe Cr is another weight gaining powder or steroid alternative (Plisk and Kreider, 1999). What those people do not know is Cr is also found in the human body naturally as opposed to supplementation.
Individuals know the name creatine but may not understand the science behind it. The use of Cr has become very widespread, usually in the supplement form Cr monohydrate. Every since the discovery of the ability to ...view middle of the document...
After synthesization occurs Cr is released into the bloodstream and is taken up via insulin-modulated active transport, stored and used by tissues with explosive or variable energy demands, especially the neuromuscular system and the heart which uses ~95% (Plisk and Kreider, 1999). Although Cr is commonly known to participate in the high energy system ATP-PC/Phosphagen system, this stipulation may be over simplified without being fully explained (Plisk and Kreider, 1999). .
After absorption, a portion of free Cr combines with phosphate to form phosphocreatine (PCr). This becomes a vital storage for energy since Cr and PCr allows rapid resynthesis of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) to meet energy demands (Grande and Graves, 2005). The body only has very limited storage of ATP and ADP. When these energy demands are made between the relationship of Cr, PCr, and ATP a reaction happens allowing the ATP to be resynthesized by Cr and PCr via creatine kinase (CK) reaction (Grande and Graves, 2005). Once utilization by the CK reaction occurs, Cr is most likely resynthezied into PCr within the mitochondria by the oxidative metabolism. Inside cells, CK activity is the primary regulator of PCr breakdown. As ADP concentrations increase, simultaneously an increase in CK activity occurs. Consenquencely, as ATP concentrations increase, CK activity will decrease. Hypothetically, Cr supplementation will increase Cr and PCr stores, aiding more PCr to be utilized in CK reactions (Grande and Graves, 2005).
Table 1 The Creatine Kinase Reaction |
Creatine Kinase (Grande and Graves 2005)
PCr + ADP ATP + Cr |
A standard of supplementation has been developed on Cr dosages. The ideal goal behind Cr supplementation is to increase the total creatine concentration (TCr). Supplementing 20g/daily for a period of 4-6days has shown to increase TCr by approximately 20% (Ehrlich, 2010). Thus, supplementation regimens have been reported to sustain ATP resynthesis and positively affect high intensity, short-duration maximal exercise performance (Grande and Graves, 2005). Cr supplementation is also found to enhance resynthesis of PCr during rest periods between repeated bouts of exercise, and prolonged Cr supplementation may increase myofibril protein synthesis, resulting to muscle growth (Grande and Graves, 2005).
There are currently 5 different ways to supplement Cr; pills, capsules, stabilized liquids, and 2 forms of powders (Antonio, 2004). One form of powder is Cr alone and the other powder obtains Cr and carbohydrates (CHO), either dextrose or maltodextrin (CHO-Cr). The supplement with the least amount of known literature for research is in the form of liquid, there has been no peer-reviewed studies to validate the effectiveness (Grande and Graves,...