BCAAs (branch chain amino acids) are a popular nutritional supplement among elite bodybuilders. It appeared on the Russian market relatively recently. Unlike the foreign press, which, with enviable constancy, since 1988, has been publishing more and more evidence of the effectiveness of this product, our scientific, sports and bodybuilding press has not yet pleased the reader with any detailed analysis. The most fantastic and ridiculous things about BCAAs can be heard from the lips of the clever "businessmen" selling sports nutrition in shops and training halls that multiply at an alarming rate. With this publication, we will try to fill this information gap so that no one can mislead you, dear reader. We will try to decide what modern sports science knows about BCAAs, what is the theory and practice of their application for our sports purposes.
Let's start with a definition. BCAAs are three branched chain amino acids from the class of aliphatic amino acids (such is the feature of their chemical structure), which are represented by valine, leucine and isoleucine. Recall that amino acids are the smallest structural units from which protein molecules are formed. Let's leave alone all the other amino acids and focus on the object of our study.
What is each one worth?
Paying tribute to the various functions performed by these amino acids, let's turn to those of them that may interest us in the first place.
Unlike other amino acids, BCAAs are metabolized in the muscles and not in the liver. They act as nitrogen carriers and also actually assist the muscles in the synthesis of other amino acids required for anabolic processes. When you eat a protein-rich meal, the fastest absorbing amino acids are the BCAAs, which seem to be by far the dominant ones when it comes to the rate of entry into the bloodstream. In fact, up to 90% of the absorption of amino acids can occur due to BCAAs in the first three hours after eating. In other words, your muscles are particularly hungry for BCAAs.
plastic function
First of all, let's understand that muscle cells are large protein molecules, while about 35% of their mass is formed due to these three amino acids - valine, leucine and isoleucine. It has also been established that they must be present in the body in order for molecular growth and development to occur. A lack of any of these will result in muscle loss.
Intense muscular activity, such as bodybuilding, powerlifting and other strength and speed-strength sports, entails the wear and tear of part of the contractile proteins. In the process of recovery, these structures replenish (and even with an excess - a phenomenon known as supercompensation) the plastic material of which they are composed. Under these conditions, it is extremely important that those amino acids are available to the body, the need for which increases sharply during the deployment of recovery processes. This requirement does not need to be explained at length - branched chain amino acids are of particular value during periods of recovery.
Contribution to muscle energy
Experiments with athletes in various sports have found that branched chain amino acids make a certain contribution to covering the energy needs of athletes during a period of strenuous training - about 10% of all energy expended. It was found that this contribution can increase under certain conditions of the organism.
For us, it is also of particular importance to understand that almost all processes occurring in the body give certain signals to the brain, and they can act both through the nerve pathways and with the help of the so-called humoral factor - through the fluid media of the body, primarily through the blood.. In other words, those substances that appear in the blood after we have taken a portion of food irritate specific receptor organs in the brain and can have a certain effect on it, thus regulating its activity, and in a specific direction.
One does not need to be a great physiologist to imagine what the activity of the brain would turn into if all the abomination that we throw into ourselves immediately influenced it. The Creator made sure that a certain barrier stood in the way of various harmful substances or compounds - and such a barrier is implemented in us in the face of the so-called blood-brain barrier.
Fortunately, the contents of our skull are well protected by this selective filtration system, which acts as a biochemical guardian, allowing some substances to enter while keeping unwanted ones out.
First, we will make a short digression into biochemistry and start not with the branched-chain amino acids we are considering, but with another amino acid - tryptophan. It is tryptophan that is directly involved in the biochemical processes that lead to the feeling of fatigue that occurs during exercise. How does this happen?
In its natural form in foods or when administered as a dietary supplement, tryptophan plays a very important role as a precursor to 5-hydroxytryptamine, also known as serotonin - one of the "big three" neurotransmitters (chemicals involved in the communication between cells in the brain). In other words, ceteris paribus, increased levels of tryptophan in the blood cause an increase in serotonin levels in the brain. And experiments have shown that exercise can and does increase serotonin levels just like taking a tryptophan supplement.
Since serotonin exerts its influence in inducing sleep and relaxation (as well as influencing mood and sensory perception), increasing its levels can be counterproductive when you're in the gym, whether you're lifting weights to add muscle mass., or spin the exercise bike to lose fat. Is it possible to prevent this not entirely desirable phenomenon? Can! This is where our BCAAs come to the fore.
Sports physiologists claim that the depletion of muscle glycogen stores during exercise results in muscle fatigue. But as the supply of this immediate muscle fuel begins to decline, BCAAs are taken from the bloodstream by the liver and sent to the exercising muscles to support their energy needs. The more intense you work, the faster the depletion of glycogen, and the more you deplete your reserves, the more significant the role that BCAAs play as an alternative fuel source.
However, a serious biochemical rival arises here. As plasma levels of BCAAs decrease, the ratio of tryptophan to BCAAs (and other amino acids) changes, leaving relatively more tryptophan available for consumption by the brain. Remember: more a significant intake of tryptophan by the brain means higher levels of serotonin in the brain, and increased feelings of fatigue and drowsiness.
It turns out that the consumption of various substances by the brain is a competition. The ratio of each individual amino acid to the sum of the concentrations of other competing amino acids determines the rate at which each individual amino acid enters the brain. Adding BCAAs to the blood stream reduces the ratio of tryptophan to these amino acids and results in less available for consumption by the brain. Theoretically, this should help slow down mental fatigue, and recent experience suggests that this is actually happening.
Preserving glycogen stores from a good diet with sufficient quality carbohydrates also helps delay the chain of events that lead to deeper and faster fatigue. Therefore, the use of supplemental BCAAs is especially important for individuals on a low-carbohydrate diet when muscle glycogen stores and mental energy can be chronically low. How can one not recall bodybuilders with their pre-competitive diet here?
Unfortunately, it must be remembered that none of the experiments conducted with BCAAs in connection with fatigue processes have offered definitive conclusions, especially those that would be addressed to the needs of bodybuilders. Researchers just don't know by now what dosages and ratios of BCAAs can reliably stave off fatigue, so it's safe to say that the manufacturers of these supplements don't either. This explains the variation in the percentage of each of the three amino acids of interest to us in the BCAA supplements available on the market.
A few years ago, researchers from several laboratories in Sweden and England (European Journal of Applied Physiology, 63: 83, 1991) conducted experiments in which runners were given a BCAA-fortified drink containing 7.5 or 16 grams of ACRC, depending on whether they were running. they are a 30 km cross or a 42.2 km marathon. Five times during their race, the cross-country group received a drink containing 50% valine, 35% leucine, and 15% isoleucine in a 5% carbohydrate solution for a total amino acid dosage of 16 grams in this drink. marathon group received a drink containing 50% valine, 30% leucine, and 20% isoleucine in plain water four times during their races, for a total BCAA intake of 7.5 grams.
While the amounts of BCAAs these runners were receiving may seem quite high, the training sessions they easily tolerated may have been somewhat lengthened. Among cross-country runners who took the 16 gram supplement, plasma BCAA levels increased by up to 140%, and in this group, the researchers found significantly reduced levels of mental fatigue compared to before supplementation with BCAA, while in the groupplacebo, this was not found. In a group of marathon runners, the researchers found that performance improved significantly among slower runners, but not among faster runners. This may suggest that BCAA supplementation may not work better during periods of intense off-season training, but during pre-competition bodybuilding training, when training patterns begin to approach aerobic through the introduction of supersets, trisets, giant sets, and significantly reduced pauses. rest between sets. Unfortunately, this is only an assumption, because, I repeat, no studies have yet been conducted in relation to the needs of bodybuilders.
Anti-catabolic influences
The value of BCAAs, of course, is more than just preventing fatigue. It turned out that BCAAs can