Las diferentes sales de creatinas dsisponibles como Creatine Ethyl Ester y Kre-Alkalyn han resultado menos eficientes que la Creatina Monohidrato.
Estos resultados fueron presentados por el Dr. Mark Tallon y el Dr. Robert Child en la última conferencia de la ISSN:
Kre-alkalyn supplementation has no beneficial effect on creatine-to-creatinine conversion rates
University of Northumbria, Sport Sciences, Northumbria University, Northumberland Building, Newcastle upon Tyne, United Kingdom, 2Department of Life Sciences, Kingston University, Penrhyn Rd, Kingston-upon-Thames, United Kingdom.
All American Pharmaceutical and Natural Foods Corp. (Billings, MT, USA) claim that Kre-alkalyn (KA) a "buffered" creatine, is 100% stable in stomach acid and does not convert to creatinine. In contrast, they also claim that creatine monohydrate (CM) is highly pH labile with more than 90% of the creatine converting to the degradation product creatinine in stomach acids. To date, no independent or university laboratory has evaluated the stability of KA in stomach acids, assessed its possible conversion to creatinine, or made direct comparisons of acid stability with CM.
This study examined whether KA supplementation reduced the rate of creatine conversion to creatinine, relative to commercially available CM (Creapure). Creatine products were analyzed by an independent commercial laboratory using testing guidelines recommended by the United States Pharmacopeia (USP). Each product was incubated in 900ml of pH 1 HCL at 37± 1oC and samples where drawn at 5, 30 and 120 minutes and immediately analyzed by HPLC (UV) for creatine and creatinine.
In contrast to the claims of All American Pharmaceutical and Natural Foods Corp., the rate of creatinine formation from CM was found to be less than 1% of the initial dose, demonstrating that CM is extremely stable under acidic conditions that replicate those of the stomach. This study also showed that KA supplementation actually resulted in 35% greater conversion of creatine to creatinine than CM. In conclusion the conversion of creatine to creatinine is not a limitation in the delivery of creatine from CM and KA is less stable than CM in the acid conditions of the stomach.
Creatine ethyl ester rapidly degrades to creatinine in stomach acid
MJ21Department of Life Sciences, Kingston University, Penrhyn Rd, Kingston-upon-Thames, United Kingdom. 2University of Northumbria, Sport Sciences, Northumbria University, Northumberland Building, Newcastle upon Tyne, United Kingdom
Creatine ethyl ester (CEE) is a commercially available synthetic creatine that is now widely used in dietary supplements. It comprises of creatine with an ethyl group attached and this molecular configuration is reported to provide several advantages over creatine monohydrate (CM). The Medical Research Institute (CA, USA) claim that the CEE in their product (CE2) provides greater solubility in lipids, leading to improved absorption. Similarly San (San Corporation, CA, USA) claim that the CEE in their product (San CM2 Alpha) avoids the breakdown of creatine to creatinine in stomach acids. Ultimately it is claimed that CEE products provide greater absorption and efficacy than CM. To date, none of these claims have been evaluated by an independent, or university laboratory and no comparative data are available on CEE and CM.
This study assessed the availability of creatine from three commercial creatine products during degradation in acidic conditions similar to those that occur in the stomach. They comprised of two products containing CEE (San CM2 Alpha and CE2) and commercially available CM (Creapure). An independent laboratory, using testing guidelines recommended by the United States Pharmacopeia (USP), performed the analysis. Each product was incubated in 900ml of pH 1 HCL at 37± 1oC and samples where drawn at 5, 30 and 120 minutes. Creatine availability was assessed by immediately assaying for free creatine, CEE and the creatine breakdown product creatinine, using HPLC (UV).
After 30 minutes incubation only 73% of the initial CEE present was available from CE2, while the amount of CEE available from San CM2 Alpha was even lower at only 62%. In contrast, more than 99% of the creatine remained available from the CM product. These reductions in CEE availability were accompanied by substantial creatinine formation, without the appearance of free creatine. After 120minutes incubation 72% of the CEE was available from CE2 with only 11% available from San CM2 Alpha, while more than 99% of the creatine remained available from CM.
CEE is claimed to provide several advantages over CM because of increased solubility and stability. In practice, the addition of the ethyl group to creatine actually reduces acid stability and accelerates its breakdown to creatinine. This substantially reduces creatine availability in its esterified form and as a consequence creatines such as San CM2 and CE2 are inferior to CM as a source of free creatine.
Lo que se puede resumir en los siguientes puntos:
* La creatina monohidrato (Creapure) tenía una tasa de conversíón en creatinina del 1% mientras que con la kre-alkalyn era del 35%.
* En una incubación de 30 minutos la creatina monohidrato (Creapure) tenía una tasa de conversíón en creatinina del 1% mientras que uno de los tipos de creatina etil ester usados en las pruebas, la CE2, era del 27% y con el otro tipo de creatina etil ester, la San CM2 Alpha, fue del 38%.
* En una incubación de 120 minutos la creatina monohidrato (Creapure) mantenía una tasa de conversíón en creatinina del 1% mientras que con la CE2 era del 28% y con la San CM2 Alpha, fue del 89%.
En este caso los análisis se han realizado en un laboratorio independiente y los estudios contrastados por una universidad (pública). Las condiciones de simulación de los jugos gástricos son las recomendadas por la USP que es el organismo que crea los estándares de referencia para estas pruebas en los EEUU.
Mas estudios sobre la estabilidad de la creatina monohidrato frente a los jugos gástricos
Acute creatine ingestion in human: consequences on serum creatine and creatinine concentrations.
Schedel JM, Tanaka H, Kiyonaga A, Shindo M, Schutz Y.
Institute of Physiology, Faculty of Medicine, Lausanne University, Switzerland.
The aim of the study was to explore the effect of an acute dose of creatine (Cr) ingestion on serum Cr and serum creatinine (Crn) concentrations. Sixteen healthy subjects ingested a single dose of Cr (20 g) followed by the measurement of serum Cr and Crn concentration for 3 h up to a maximum of 6 h (n=6).
In response to Cr ingestion a large rise in serum Cr concentration was observed (by 50 folds) occurring approximately 2 1/2h after the ingestion (peak value of 2.17 +/- 0.66 mmol x l(-1)). We also found a moderate but significant rise in serum Crn concentration averaging 13 % after 3 h (peak value at 99.5 +/- 10.5 micromol x l(-1)).
A dose response curve obtained in two case studies, in whom different doses of Cr were ingested (0, 2.5, 5, 10, 15, 20 g and 0, 10, 20, 30 g), showed that serum Cr concentration as well as the peak time increased linearly with Cr ingestion. In addition, acute Crn ingestion (5 g) resulted in a substantial increase in serum Crn concentration (by 10 folds) but led to a minor rise in serum Cr concentration (by 2 folds).
These results suggest that when acute doses of Cr are ingested in humans, the degree of conversion of exogenous Cr to Crn in the stomach and the gut can be considered as negligible following the first 6 h of ingestion. However, further studies are required to explore the prolonged effect of Cr on Crn metabolism.
