What are BCAAs and how do they work

Branch-chained amino acids or BCAA’s are one of the most used nutritional supplements in the fitness world and are considered the perfect compliment for those who want to gain muscle mass and reduce their body fat. Furthermore, they can also be a very beneficial complement in the world of Endurance training as they protect our muscle mass structure and help us avoid muscle loss during intense training and recover after sports training.
What are BCAAs?
BCAA’s are referred to the group of branch-chained amino acids that form leucine, isoleucine and valine. They constitute, approximately, a third of the muscle protein within our skeletal muscle and is one of the main reasons why their use is advocated as a sports supplement. They are essential amino acids as the human body cannot naturally produce them and, therefore, need to be ingested through our diet. Moreover, they represent roughly 40% of the required daily intake essential in the male.
Of the three amino acids which constitute BCAA’s, the most important, according to scientific evidence, seems to be leucine due to its principle role in muscle protein synthesis (MPS, Muscle Protein Synthesis) (Crowe et al., 2004; Kreiger et al., 2010; Norton et al., 2006; Pasiakos et al., 2014). In fact, they are naturally found at a ratio of 2:1:1 (leucine, isoleucine, valine) in the skeletal muscle which means that for every 4g of BCAA’s, 2g would be leucine, 1g isoleucine and 1g valine. Thus, the required daily recommendation is around 40 (LEU), 20 (ISO) and 20 (VAL) mg/kg weight / day, respectfully, for healthy individuals who are not necessarily athletes (Kurpad, Regan, Raj & Gnanou, 2006).
Why are BCAA’s important for endurance athletes?
BCAA’s are the ideal nutritional supplement for those who are looking to gain muscle mass and those who are looking to lose body fat. Whatever your sporting goal may be, you can benefit from the properties of BCAA’s in different ways.
An important characteristic regarding branch-chained amino acids is that they do not deteriorate the liver, instead they flow directly into the bloodstream and are, therefore, easily available for the skeletal muscle and other tissues. However, the liver can oxidate them after the transamination  (free separated amino acids via amino transfer or transaminase) process within the muscle and other target tissue has occurred. For this reason, within the sports world, it appears it could be especially useful, when training / a competition are close, to consume them before, during or after it.
Evidence suggests that during stressful moments the body cannot produce sufficient glutamine to keep up with the daily demand, something that, in turn, can reduce performance, lower the immune system’s defenses and an individual’s mood. Athletes at risk of suffering a glutamine deficit include those who do not consume enough calories, carbohydrates, and protein or those who participate in prolonged endurance. It is believed that the plasmatic response to the formation of glutamine is two-phase, which means, a concentrated increase during intense training followed by the reduction of the concentration after prolonged exercise. Various writers have shown that our plasmatic levels of glutamine are reduced by up to 25% after running a marathon. As a result, the necessity for adequate daily nourishment is important in order to help maintain stable levels of glutamine.
Branch-chained amino acids are interesting and useful for several things however, without being too extensive, I will highlight the following:
Post Exercise Recovery: after exercising, one of the first things we should try to deter is muscle breakdown (catabolism) and stimulate the opposite processes, muscle regeneration and reconstruction (anabolism). This is where BCAAs play a very important role. Moreover, they help to lessen the effects of muscle breakdown that have been produced, reducing the effect of Creatine Kinase (CK) and Lactate DeHydrogenase (LDH).
Central Fatigue Reduction: Although not 100% clear, there appears to be a connection between the plasmatic concentration of BCAA’s. This affects the release of neurotransmitters, to a greater or lesser degree, and is a key factor in this type of fatigue, one that does not originate in the muscles but in the central nervous system.
Immune System Stimulation: This occurs in an indirect rather than direct fashion as BCAA’s, it appears, stimulate the synthesis of glutamine. This is connected, predominantly, to the presence of certain white blood cells.
Energetic Substrate Provision: In this case, two separate processes form the production of BCAA’s. Firstly, they aid muscle glycogen metabolic processes or, secondly, they themselves are the energetic substrate. In the second case, they are not a massive source of energy as they are not the most efficient form of metabolism. Furthermore, they do not contain a large source of energetic value however, the fact that they are being consumed, helps to protect the existing glycogen reserves.
An important fact to keep in mind is that BCAA’s, given their quality as free amino acids, are assimilated at an astonishing rate without needing digestion to be available for use within the muscles. This also avoids body dehydration in the process.
BCAA’s are not recommended in the following cases:
1 – Pregnancy and breastfeeding: If you are pregnant or breastfeeding, it is not recommended to consume branch-chained amino acids due to the lack of sufficient, reliable evidence to suggest it is safe to do so.
2 – Before an operation: It has been demonstrated that BCAA’s affect sugar levels in the body, therefore it is not recommended to consume them before an operation. If you consume them, it is advisable to stop at least 2 weeks before the operation.