Competitive Sports and Need for Amino Acids, BCAAs

During particularly prolonged stress, carbohydrate stores are depleted and protein reserves are used as a source of energy. As a result of prolonged intense athletic activities, amino acids are thus increasingly depleted. In particular, valine, leucine, isoleucine, threonine, methionine, phenylalanine, tryptophan and lysine cannot be formed by the body, which makes it urgently necessary to supply them via the diet. Furthermore, arginine, ornithine as well as glutamine are increasingly burned, since intensive competitive sports always bring catabolic processes and hormonal changes in the body.

Of particular importance are BCAAs – branched chain amino acids

BCAAs (branched chain amino acids) or branched chain amino acids, consist of three amino acids leucine, isoleucine and valine, which belong to the group of essential amino acids. Essential means that the body cannot produce them itself, but is dependent on a supply through food. The term ́branched-chain is based on the special chemical molecular structure of the three amino acids, for which an interlocking of the methyl groups is characteristic. From this property, a first important requirement for the supply can be derived: BCAAs can only develop their full effect if the three amino acids leucine, isoleucine and valine are taken in with food at the same time, if possible. To understand the importance of branched-chain amino acids in sports, it is important to understand the properties of muscle tissue. It becomes interesting to take a closer look at the amino acids found in muscle cells. The amino acids most abundant in skeletal muscle are glutamine and alanine, which are present in a 10:1 ratio of amounts. When the body is faced with intense exercise, the following situation occurs: large amounts of glutamine are metabolized to alanine, which is released from muscle cells into the blood to increase glycogen production in the liver. This is associated with an increased release of ammonia in the liver, which is excreted by the kidneys. The end result is that glutamine is lost to the muscle, and its nitrogen is ultimately excreted through the urine, negatively affecting the nitrogen balance. It is important to replenish the glutamine depots lost during training in order to prevent a catabolic, i.e. degradative, state for the muscle cell, in which muscle tissue is metabolized. Otherwise, this would have the consequence that the athlete would lose muscle mass and thus strength and power endurance. Therefore, both during and after physical exertion, the muscle cells primarily try to produce glutamine from other amino acids. The three BCAAs leucine, isoleucine and valine offer themselves as sources for the build-up of glutamine. There are three options to choose from:

• The body metabolizes its own muscle tissue and extracts from it BCAAs, which after all account for 35% of all essential amino acids contained in the muscle.
• The body uses less BCAA for a further protein build-up at first.
• The muscle cells cover their increased needs via the so-called free BCAAs in the bloodstream, which are not yet bound to body cells

The first two options come at the expense of muscle gain or muscle maintenance. They must be avoided. The only reasonable strategy shows the third way to ensure the supply of free BCAA to muscle cells through the bloodstream. Consumption of BCAA-rich supplements can ensure high plasma levels of BCAAs. BCAAs, or branched-chain amino acids, are not metabolized in the liver after consumption and their absorption into the blood – in contrast to other amino acids – but directly in muscle tissue. They can therefore be used by the muscle cells directly and without delay to form used glutamine, which is why the body does not have to resort to its own muscle tissue. This means that if BCAAs are ingested or consumed at the right time, they have the ability to protect the athlete from a breakdown of muscle substance. In this context, one also speaks of an anti-catabolic effect of the branched-chain amino acids. Therefore, BCAAs should be taken 60-90 minutes after training, since the amino acid uptake into the muscle cells is most effective at this time interval from the sporting activity.To ensure optimal absorption, i.e. enrichment of the blood level, it is recommended to combine it with a meal. This additionally leads to a stimulus of the pancreas and thus to an increased insulin secretion, which further enhances the transport of amino acids into the muscle cells. Studies on the mode of action of BCAAs in humans indicate that their administration may result in a direct anabolic effect. Leucine, isoleucine and valine have the potential to influence certain hormonal processes, with leucine in particular having some interesting properties to offer. A growing number of publications suggest that leucine increases serum levels of human growth hormone (HGH); somatotropic hormone (STH); growth hormone) and increases both insulin and liothyronine (T3 thyroid hormone) secretion. Liothyronine has an anabolic effect, as it positively influences protein biosynthesis (formation of new proteins) in the muscles and also activates the burning of carbohydrates and fats for energy. Furthermore, BCAAs, especially leucine, serve as an energy source for the muscle cells. During physical exertion, L-leucine is oxidized directly in the muscles. The rate of oxidation increases proportionally with exercise intensity, indicating that the leucine requirement of muscle cells depends on their energy demand. In situations characterized by decreasing or low glycogen stores in the muscle cells, such as a calorie-restricted and carbohydrate-restricted diet or the end of an energy-sapping training session, leucine in particular can be quickly and easily used by the muscle cells as an energy source. The body’s main energy suppliers are known to be carbohydrates and fats. When these are used up as energy suppliers and there is an energy deficit, the glucose serum level drops: the body now produces glucose “on an emergency basis” – through so-called gluconeogenesis (gluconeogenesis from glucoplastic amino acids) – from its own proteins (muscles) and thus ensures various basic energy needs: Erythrocytes, for example, are dependent on the supply of glucose, since their energy production – without mitochondria – is based solely on glycolysis. In muscle cells, gluconeogenesis plays a significant role as a component of the glucose–alanine cycle, which is responsible for the transport of alanine [after transamination of pyruvate to alanine] from the muscle to the liver, and for the return transport from there [after transamination of alanine to pyruvate] of glucose formed by gluconeogenesis into the muscle. Alanine is the central amino acid when it comes to ensuring a reasonably stable serum glucose (blood glucose) level during athletic exercise. In other words, during a heavy training session, alanine is converted in the liver to glucose, which can then be supplied to the muscles as energy. For the athlete, in this context, the adequate supply of BCAAs primarily ensures that sufficient amino groups are always available for this cycle for the transamination of pyruvate to “its” transport form alanine. It is also assumed that the availability of BCAAs in the muscle can lead to an increase in the lactate content: On the one hand, this serves the direct energy production, on the other hand, lactate is supposed to accumulate in this way, which can be supplied again to gluconeogenesis in the liver via pyruvate. In any case, it is scientifically proven that an increase in the endurance performance of athletes can be observed after the intake of BCAAs. The administration of BCAAs before training is not without risk, because with such an intake procedure the urea levels increase and strain the body. The same problem occurs, of course, when the athlete wants to take advantage of the energy-providing, endurance-enhancing effect of the branched-chain amino acids. Endurance athletes in particular, such as marathon runners, like to take BCAAs shortly before the race in order to have more energy “out the back”. To ensure that no health risks arise from the increased urea load, it should only be taken for a short time or irregularly before training. Those who eat well and regularly take branched-chain amino acids will make better progress in the long term in sports, whether endurance and/or strength loads than without BCAAs.Athletes on a calorie-restricted diet should definitely give BCAAs a try, as they can help preserve valuable muscle mass with their anti-catabolic effect. The same applies to endurance athletes, who have been shown to benefit from the energy-supplying properties of branched-chain amino acids when they are administered approximately 30 minutes before training/competition. The question of the most effective dosage of leucine, isoleucine and valine for performance enhancement is difficult to answer. The fact is, the more intense the training, the more frequent and longer the training, the better trained or conditioned you are, and the higher your body weight, the greater your need for BCAAs. The estimated daily requirement of branched-chain amino acids for hard-training athletes is:

• Leucine in the range of 5-6 grams / day.
• Isoleucine at about 2 grams/day
• Valine to be between 4-5 grams/day.

Important in this context is the word ́Daily requirement́, that is, the dosage information also includes the BCAAs supply with the daily food and must therefore not be covered exclusively with amino acid tablets. For the competitive athlete, not only the choice of amino acid, but additionally the provision of a sufficient quantity is of importance, since as a rule there is always an additional protein requirement.

A strength athlete seeking muscle gain has a daily protein requirement of 1.4-1.6 g per kg body weight. However, competitive sports do not challenge muscle metabolism alone, but all antioxidant, metabolically active, or metabolic harmonizing processes. Sports exhaustion is often associated with an increased susceptibility to infections, which indicates an exhaustion of the immune system. Competitive athletes in particular often exhibit deficiencies in the supply of general vital substances (macro- and micronutrients). Therefore, in addition to a balanced supply of high-quality protein, athletes should also supplement with vitamins, minerals and trace elements. Recommended for endurance and strength sports is the intake of a dietary food for intense muscular effort. For endurance and strength training, have your physician prepare an individual fitness plan (e.g., based on an athlete’s checkup).