Everyone loves glutamine, they rush with it, care for it and cherish it. No, of course, they don’t feed, but it feeds more than one generation of producers of what is called “sport nutrition”.
What is it, in fact, is it?
common amino acid. Glucogenic, that is, produced by glucose. If someone decided that it is irreplaceable, then they were mistaken: glutamine is quite successfully synthesized by our body – both in skeletal muscles and in the liver. So successful that in his blood is the most. Approximately 2/3 of the amount of free amino acids in our body falls on glutamine. Need an amino acid? Undoubtedly! Glutamine performs many functions in the body: it serves as a kind of “shuttle” that delivers nitrogen to organs, is a fuel for the immune system, and a precursor of nucleotide synthesis. And it is also able to give the cell volume – under the influence of glutamine, the cell swells. This increase in volume stimulates anabolism, that is, the synthesis of proteins and glycogen, and suppresses catabolism. Thus, according to scientists, glutamine plays a regulatory role in protein synthesis throughout our body. Well, what else could be more important for us?! True, it is worth immediately making one, but very important remark: most of the studies concerning the role of glutamine in the body took place on cell cultures or animals – as a rule, they were laboratory mice. Experiments on living people will be discussed below.
Above, I wrote that glutamine is successfully synthesized by our body, so it cannot be considered an essential amino acid. This is true, but sometimes its synthesis can be difficult. This happens at times of physical stress, and one of the sources of such stress is weight training; at this point, the body requires, as the researchers believed, more glutamine for its successful life than it produces. That is why these same researchers called glutamine a “conditionally essential” amino acid. This fact was also one of the reasons that glutamine began to be used as a sports nutritional supplement.
Experiments on people: we have something to tell you!
At first it seemed that experiments on humans only confirm all of the above. It was carried out, and as a result they began to be approved with all responsibility following:
glutamine supplements can prevent the breakdown of muscle tissue after such severe physical stress as surgery;
since glutamine is a fuel for the immune system, when taken as a supplement, it can increase the body’s resistance, in particular in case of overtraining (studies were conducted mainly on marathon runners, only one of them concerned bodybuilders);
glutamine supplementation can approximately double the capacity of muscle fibers to store glycogen – at least two studies confirm this fact.
It is these results and these claims that numerous sports nutrition manufacturers have adopted in their advertising of glutamine. But…
but on the other hand
Every medal has a reverse side – an indisputable fact. Sometimes it turns out not to be unsightly – rather, it can overshadow everything that is “embossed” on the front side. It was this kind of reverse side that turned out to be with the glycogen “medal”. It all started with the unexpected results of a study conducted in 1999.
This study compared the effects of the amino acids glutamine and alanine on protein synthesis in rats. To the surprise of the researchers, it turned out that a 60% decrease in muscle glutamine levels – and this is quite a lot – had no effect on protein synthesis. Even more surprising was the fact that restoring muscle glutamine levels to baseline also had no effect on protein synthesis in the body. Absolutely none! Another similar study was conducted, after which the scientists were forced to declare that a reduced or increased level of glutamine in the muscles, most likely, does not have any effect on protein synthesis.
The next study was conducted in 2000 in humans, but the findings remained unchanged: the addition of glutamine to the mixture of amino acids taken after training had no effect on protein synthesis. While the intake of an amino acid mixture after training increased protein synthesis by 50%. So adding glutamine to your post-workout protein shake does absolutely nothing. Here are those times!
And what about our immunity?
And here are those two. A study conducted in 2002 attempted to establish relationship between plasma glutamine levels and immune suppression resulting from heavy resistance training. It turned out that, contrary to theory, there are no special changes in the level of glutamine in the blood plasma after training. It is even more interesting that these changes have a completely different quantitative expression, but immunity always falls, and quite significantly.
A few more studies, conducted, like the above, on humans, showed that taking glutamine supplements does not in any way affect the fall or increase in immunity. How do you conclude this: “although glutamine obviously plays an important role in the course of metabolic processes in the body, its supplementation does not lead to any therapeutic effect, except for conditions characterized by an increased level of catabolism.”
What does the above mean? It’s simply that taking glutamine supplements to boost a weakened immunity during training is, by and large, as useless as bowing to the image of Arnold Schwarzenegger to gain muscle mass as soon as possible.
The last “stronghold” – glycogen
You know what’s interesting? In addition to research in favor of the “glycogen theory”, there are studies that refute the fact that glutamine supplements in any way affect the accumulation of glycogen spent during high-intensity training. What’s the matter here? It turned out that everything is simple: those studies that talked about the benefits of glutamine for the accumulation of glycogen were based on cases where “glycogen depots” turned out to be 90% depleted. But in this case – with or without glutamine – the body really accelerates the accumulation of spent glycogen. But in the case of weight training, when glycogen levels fell by an average of 36%, glutamine no longer accelerated anything.
And one more thing
Among other things, it will be very interesting to see how and where glutamine is used in the body. Firstly, oral glutamine supplements have very low bioavailability – it is at the level of 42-43%. This happens, in particular, and due to the fact that the cells of the gastrointestinal tract are happy to use glutamine as fuel. Secondly, many other cells of our body do the same, in particular, the already repeatedly mentioned immune system. systems. So very little glutamine will reach the muscles.
Glutamine seriously irritates the gastrointestinal tract, so taking it in large quantities at a time (about 20 g) can cause gastrointestinal disorders. True, at least one experiment conducted on bodybuilders who took glutamine at the rate of 0.3 g per kilogram of body weight per day did not reveal any disorders. However, no beneficial effects were found. Somewhat later, another experiment was conducted in which the daily dose of glutamine was increased three times. The result is the same – no harm (huh, relieved!), But no benefit either.
So what to do?
It has been repeatedly written that the use of androgens and anabolic steroids leads to an increase in the synthesis of glutamine by the body. So taking glutamine supplements while you’re on cycle is just a waste of money. No, if you want, then please – your will. But I think there are better uses for money.
But even “natural” athletes are unlikely to be able to extract something useful from glutamine supplements. If we are talking about accelerating protein synthesis, then it would be more appropriate to turn to ordinary protein drinks, as well as amino acid complexes without any high glutamine content there. Especially useful before and after training will be BCAAs. If we are talking about increasing immunity, then it would be much more logical to take antioxidants – vitamins E and C in high doses after training. Those who are seriously concerned about the fall of immunity can turn to the help of interferon.
Finally, if you are interested in the accelerated accumulation of glycogen, then the emphasis should be on the use of high-intensity training methods that, coupled with an appropriately organized diet, can exhaust the “glycogen depots” in the body almost “to zero”. We have written about something similar before.
So what about glutamine? I think it is worth leaving it for those cases when the body is in a deep “catabolic pit”, in particular, with massive treatment with glucocorticoids (for cancer, for example), or in the case of septic diseases. This is where it can come in really handy.