
Originally Posted by
BrokenBricks
Well, I don't know the effects of massive ingestion. However the guys post is packed with inaccuracies so I doubt he does either.
Let me change the terms here a bit since not many people use the term "glycocamine" in the research the word guanidinoacetate is used. Same thing. Abbreviated "GAA"
So here is the quick and dirty. Normal physiology, you and me. You eat proteins and liberate glycine and arginine from the food. These amino acids, upon entering the kidney encounter l-arginine:glycine amidinotransferase (AGAT) which converts glycine and arginine into ornithine and guanidinoacetate (GAA), our chemical of interest. So your body makes this stuff, it leaves the venous drainage of the kidney and works its way to the liver where it encounters guanidinoacetate methyltransferase (GAMT). A methylation takes place converting GAA into creatine. The creatine is absorbed by the muscle and there is much rejoicing.
So #1, You *need* GAA. The only question becomes, is the normal human level just right, or is there benefit to adding more? More specifically you *need* creatine. If you ingest intact creatine this would reduce the amount of GAA in your body. Maybe that is desirable. To know that we have to go a little deeper. But what should be obvious at this point is that muscle cells having the ability to convert GAA to creatine is irrelevant. The liver accomplishes this task. Not looking so great for Jerry.
Oh so, whats up with homocystine? What is up with seizures?
Homocystine. No evidence directly suggests homocystine is toxic. What is clear is that people who tend to have high homocystine levels are, over decades, more likely to have heart disease. Now what does that mean? It is easy to be lazy and say well homocysine is "bad" and anything you can do to reduce it must be desirable. That *could* be true, but let me paint another picture. Look at Creatinine. In this very thread someone called it "toxic". That is *wrong*. Why did they say that? Because people with high creatinine tend to have poor renal function. So creatnine causes renal disease? NO! Creatinine is for all intents inert. It is just one of thousands of waste products that the kidneys excrete. When you have kidney problems ALL of those products build up in the blood. We happen to use creatinine as a nice handy test of renal function becuase in general your body makes a steady amount of it, so if creation is constant the only variable is elimination and hence you can infer renal function from it. So while MOST people with an elevated creatinine have a renal problem that is just a coincidence of the fact that more people have kidney disease than there are people who do things which increase actual production of creatinine. Who are those people? You and me! People with high muscle mass break the rules. We make a ton of creatinine, our levels are higher, and it has nothing to do with the kidneys. If you are injesting creatine your level will be even still higher. What was my point? On a superficial glance it would have appeared that creatinine was toxic to kidneys. It is not. It takes knowing the physiology to understand why. Well in the case of homocystine all we know is that people with heart disease tend to have higher levels. It is not at all proven that the CAUSE of heart disease is homocystine or that keeping your level lower artificially is protective.
Anyway, the same enzyme that converts homocyctine into an excreteable form is the one which converts GAA to creatine. If you eat a lot of GAA you will shift the balance of the enzyme toward GAA and away from homocystine. the levels go up a bit. What relevance that has is anyone's guess.
Seizures. Some kids are both without the enzyme (GAMT) to convert GAA into creatine. GAA builds up to extremely high levels and the kids get seizures. Now this stuff is in all of us all the time and does not cause seizures. When it is hundreds of times normal value it does. Does letting the value double or triple matter? No.
Assholes like Jerry can skim and article in pubmed, and then write phrases like "Such and such is associated with seizures!" and scare their readers. the reality is that while yes, GAA is associated with seizures so is table salt...so is water. What the guy says is true in the sense that "association" can mean even nearly anything, but then the guy uses the phrase in a way which communicates a very specific intent which is *not at all* supported which is "If you take this you are at risk of having a seizure". This style of writing is rampant in the BB community and it is obvious why. Evidence is *hard* to come by, but innuendo and a veneer of scientific rigor can move product and sell magazines.
Would I take GAA. No I would not. It is shown that eating GAA will increase your creatine levels. But it does so in a convoluted way which intersects many other biological functions. (GAMT) catalyzes essentially every methylation in the body. Figuring out the effects of augmenting that activity is impossibly convoluted. What is not convoluted is realizing that whatever the benefit of GAA, it only comes via the increases in creatine. I could just take more creatine! The stuff is simply redundant. Don't substitute a great drug which is know to be uncomplicated with one that is at *best* no better that just taking creatine.