The branched amino acids (or BCAAs) are three particular amino acids called Leucine, Isoleucine and Valine, which belong to 8 essential amino acid group. They are named this way, because the body is unable to synthesise them autonomously starting from other substances but must take them from outside sources.
BCAAs are the most represented amino acids in skeletal muscle, constituting about its 35%.
These three amino acids are characterised by the fact that, once ingested, they are rapidly absorbed like free amino acids. However, unlike the latter, they bypass the hepatic metabolism to be directly introduced into the blood and quickly reach the brain and muscles. Inside the last two mentioned, they favour the synthesis of other types of amino acids which are important for gluconeogenesis.
Inside the blood-brain barrier, on the other hand, they compete with free tryptophan. This, in turn, is a precursor of serotonin (the neurotransmitter responsible for the sensation of fatigue), which hinders the production of serotonin, thus attenuating and delaying the feeling of fatigue.
Leucine, in particular, stimulates the initiation phase of protein synthesis through the stimulation of the so-called mTORC1 “anabolic signaling pathway”. Specifically, it acts as a sort of sensor activator that starts a whole series of cascading signals inside the body, to which they communicate to increase the rate of protein synthesis.
By virtue of the particular role that Leucine plays in activating muscle protein synthesis, commercially available BCAA supplements usually provide a greater amount of Leucine than the other two amino acids. This is typically twice as much, hence the abbreviation 2.1.1, or even with higher leucine ratios, 4.1.1, 8.1.1., or above.
The first studies on mice had been very encouraging regarding the effects following an increase in muscle protein synthesis.
However, when it came to man the benefits deriving from the intake of only BCAAs were transient. The reason for this is that they decay when the process of protein synthesis clashes with a deficiency of one of the other EAAs.
So if the purpose is to maximise muscle protein synthesis and therefore anabolism, for example, in peri-workout, it would be ideal to take all the essential amino acids EAA (I invite you to read about the article dedicated only to essential amino acids which illustrates, in a very thorough and documented way, the effects of the EAA on the MPS).
Similarly, very high doses of Leucine (greater than 2g) were found to be more effective only in old age individuals.
Therefore, in the current state of scientific research there is no rationale in the use of supplements by athletes who display amazing and miraculous dosage and ratios.
Yamamoto Nutrition® offers various formulations of BCAAs. These, obtained by vegetable fermentation, come in 2.1.1., 4.1.1. or 8.1.1 ratios, both in capsules and powder.
The top of the range is represented by the BCAA PRO line in which the raw material is made of Kyowa BCAA, extracted by bacterial vegetable fermentation (process owned by the company Kyowache guarantees maximum purity).
Agnese Russo, Graduate in Dietetics and Engineering, IFBB pro league professional athlete, Yamomoto Nutrition Research Team.