Hey Steve,
You are making yourself very clear and so I would say your English is fine!
I would not say we are wholly disagreeing as much as clarifying...the research and what is known about Creatine is a growing body of knowledge in place already...so we are not really discussing personal opinions...we are discussing our interaction with this body of knowledge.
Just to be clear..my interest is in the study and application of sports physiology and performance and sports nutrition.
I have not read
all of the over 500 published studies and even what I have read seems cursory.
In answer to your question, I am not a sales person. I am a trainer and consultant.
For my information I rely on research, texts, published articles by accepted experts, peer reviewed articles, lectures and discussions with and by experts in the field of Sports and related research...such as Wayne Wescott and William Kraemer.
I admit, my understanding of the cellular "mechanics" of Creatine supplementation vs Synthesis is not absolute..my understanding is...
For instance, that Creatine is
synthesized (meaning assembled from parts) from the amino acids glycine, arginine and methionine in the kidneys, liver and pancreas. Free Creatine circulates in blood and in muscle tissue, where it can be converted to Phospho-Creatine with the transfer of a phosphate group or contribute a phosphate group to make ATP
ADP + PCr + H+ <---> ATP + Cr .
The body appears to have a target level for circulating Creatine, and ingestion or supplementation reduces synthesis by the body. There also appears to be a balance between intracellular Creatine (about 60%) and Creatine circulating in blood (about 40%.) Within a few days of supplementation, intracellular Cr levels reach a new equilibrium level. A much smaller fraction of this additional Creatine appears to be stored in the high-energy phosphocreatine form.
The supplemental Creatine is not
synthesized in the kidneys, liver and pancreas, it is
supplied. Then, Creatine is
eliminated through the kidneys...in a volume equivalent to 1-3g/day in non supplementation or roughly equal to the amount supplemented...as creatine or creatinine.
Because Creatine is eliminated through the Kidney it has been believed there may be some risk to the kidney from supplementation, however to my knowledge there has not been any research which actually showed people with normal kidney function having any indicators of adverse kidney function. Naturally higher intake of Creatine increases kidney involvement.
Studies like, "Long-term Creatine supplementation does not significantly affect clinical markers of health in athletes." Mol Cell Biochem. 2003 Feb;244(1-2):95-104. Have found no clinical markers for long term (21-month) use in athletes. According to Dr. Kreider and coworkers, when compared to the group of football players who did not take Creatine, the football players who took Creatine actually had
fewer episodes of cramping, dehydration, muscle tightness, muscle pulls and strains, non-contact joint injuries, contact injuries, illness, number of missed practices due to injury, players lost for the season, and total injuries or missed practices.
Now, You are saying Creatine is NOT a nutrient found in food?
That is like saying amino acids in protein are not found in food.
Creatine occurs naturally in fish and meat, and is found in skeletal muscle, heart, brain, retina, testes and the uterus....etc.
When you take it away, function declines, when you return it to the diet, function returns.
There is some discussion about making it an essential nutrient....you feel that is not valid?
though it seems not to work for women ( no scientifical proof of improving muscle size and muscle/fat ratio)
This is wrong. Studies show it is effective in women who do short intense training.
what do you mean by effective studies show that it is not for improving muscle size and muscle/fat ratio
To quote a meta-analysis
Effect of Creatine supplementation on body composition and performance: a meta-analysis.
Branch JD., J Sport Nutr Exerc Metab. 2003 Jun;13(2):198-226
"There were no differences from Creatine supplementation on effect size for body composition or performance between males and females or between trained and untrained subjects. There is no evidence in the literature of an effect of gender or training status on effect size following Creatine supplementation."
You know, I could probably pull out study after study that included women that show that female lifters experience similar training effects from Creatine supplementation.
There is a brief discussion of the importance of supplementation, including Creatine, for women strength athletes...
Nutritional Aspects of Women Strength Athletes.
Volek JS, Forsythe CE, Kraemer WJ.
Br J Sports Med. 2006 Jul 19;
You know that women's physiology is nearly the same and the difference in most subjects would be the amount of muscle in which to store Creatine, or the relative volume of Type IIb Glycolytic and Type IIa Oxidative/Glycolytic muscle fiber.
It is not as beneficial for these athletes but it still has benefits and their Creatine phosphate systems still supply short bursts of energy!
yeah but this effect only goes after training so it is useless while doing marathon and other endurance sport
During the sprint at the beginning and end of a bike race or other long distance race...the ATP will be called upon and the Creatine phosphate system will be critical to the performance of that sprint.
Performance enhancement is what this athlete would look for, not increase in muscle mass...
whats youre point now
I was surprised that you expressed "Creatine is not effective for those who practices endurance sports" especially due to the risks you mentioned.
I was surprised that you expressed that "it seems not to work for women (no scientifical proof of improving muscle size and muscle/fat ratio)"
Are you a researcher, student, etc..please tell me how you come to be a "student" of performance nutrition science?
I hope this conversation seems to be along the lines of a reasonable conversation/debate...I am happy we are having this as it gives me a chance to check my clarity/accuracy...you know, when you talk to most lay people they just want the sound-bite and it is hard to give in-depth and clear info in a short burst!!!
It is unfortunate that you would say "Anyway im just wandering why you post bulls*** like this OMG and youve got 3620 post" Especially as I can relate all my comments to peer reviewed, published research.
<message edited by danmirage on Wednesday, August 23, 2006 1:06 PM>