elars, honestly, the more I read about glutamine, the less impressed I am. Sadly, some people even equate it with creatine, even though the sports research on glutamine died years ago.
WRT buffering, I will preface the answer by saying that I’m not very concerned by acid base balance in a healthy adult. Maybe I’m missing something, but from what I’ve read, I can’t make its focus a priority.
Abundance in our body reflects versatility, meaning that it can be converted to other things. Supplement companies have done a great job convincing people that the intuitive notion of abundance= magical importance. We’ve all heard that glutamine is the most abundant amino acid in muscle, but of the 20 aa’s in muscle protein, glutamine is 4th lowest in concentration.
The buffering idea is also largely discredited by the Antonio study, where glutamine supplementation had no effect on lactic acid buffering during exercise.
As far as the gut using glutamine, its for protein synthesis. It is the studies on whole body protein synthesis that are often used by companies trying to show that glutamine will enhance muscle growth. Sad. Note that if glutamine is being used by the gut, it can’t be used by the rest of the body for buffering.
I don’t think that serious acidosis occurs in healthy people, even while on low carb. But again, glutamine would be used for processes other than buffering in this situation.
If you’re really into buffering, you could look into beta-alanine supplementation, but that’s another story altogether.
elars, thanks for your patience WRT this reply -I know I went on several tangents. I really like your thinking, but don’t believe that glutamine will help buffering.
END GLUTAMINE RANT
[quote]elars wrote: This seems to be a good reason for glutamine supplemementation. Perhaps also why it is the most abundant amino acid in our bodies:
In Influences of nutrition on acid- base balance Remer found “protein itself moderately improves the renal capacity to excrete net acid by increasing the endogenus supply of ammonia which is the major hydrogen ion accepetor.” Ammonia+ Hydrogen ion yields ammonium.
Here’s part of an encyclopedia definition of glutamine.
Its structure is identical to that of glutamic acid, except that the acidic side-chain carboxyl group of glutamine has been coupled with ammonia, yielding an amide. The glutamic acid-glutamine interconversion is of central importance to the regulation of the levels of toxic ammonia in the body. Glutamine can donate the ammonia on its side chain to the formation of urea (for eventual excretion by the kidneys) and to purines (necessary for the synthesis of genetic material). Once glutamine is incorporated into proteins, its relatively unreactive side-chain amide participates in very few reactions.
Just re-read, your glutamine articles. They’re great. Believe it or not they further my belief. You said up to 40% of glutamine can be used by the GI system. Would this have to do with the buffering of dietary protein?
You also said that it is beneficial on low carb diets. We know that it is one of the most glucogenic of amino acids, so there’s an obvious benefit. But low carb also means high protein, and for a lot of dieters hardly any fruit-and how many people do you know will actually eat their broccoli,spinach, etc. This would lead to a very high net acid load. Massive amounts of glutamine would be needed to buffer, and likely catabolized from muscle tissue or sever acidosis could ensue.[/quote]