Function of Branched-Chain Amino Acids (BCAAs)

What is it?

In animal proteins (including human beings), the ratio of branched-chain amino acids (BCAAs) L-Leucine, L-Isoleucine and L-Valine is respectively 2:1:1. In other words, the proteins that make up our body contain L-Isoleucine and L-Valine in equal measure, and a double amount of L-Leucine. For this reason, the first BCAA supplements released in the market were formulated in the 2:1:1 ratio. Recent studies have shown, however, that L-Leucine has a key role in the protein synthesis stimulus in various body regions, including skeletal muscle. In fact, once transported inside the cell, L-Leucine stimulates the activity of mTOR (mammalian target of rapamycin) (Zhang et al., J Anim Sci Biotec, 2017), a protein that once activated triggers the synthesis of new proteins and cell growth. L-Leucine is therefore not just an essential brick with which our proteins are built, but it is also an activator of their synthesis. In fact, the concept of 'leucine threshold' has been brought forward, namely that only when a certain minimum leucine content reaches the inside of the cell can an anabolic stimulus be received (activating mTOR) (Phillips, Sports Med , 2014). This implies that a protein source having a high percentage of BCAA, and in particular of L-Leucine, is crucial to give an anabolic stimulus in the post-workout phase. Based on this new information that ongoing scientific research provides, the latest formulation of BCAA 8:1:1 (ie, where the amount of L-Leucine is 8 times higher than the other two branched amino acids) makes it easier to reachy the 'Leucine Threshold' and is therefore particularly suitable for athletes whose goal is to increase muscle mass. It should be remembered that despite the fact that L-leucine plays a key role in protein synthesis, it works in synergy with the other two branched-chain amino acids, whose presence is equally important.

Some studies also suggest that BCAAs reduce the sense of fatigue at the level of the nervous system (Blomstrand, Acta Physiol Scand, 1997). The presence of branched amino acids in the body reduces the inflow of tryptophan (a precursor to serotonin, the neurotransmitter responsible for tiredness) to the brain by reducing perceived fatigue (Newsholme & Blomstrand, J Nutr, 2006).

They can also become an alternative energy source – during resistance training our body needs energy that is preferably obtained from carbohydrates, then from fats, and finally from proteins, then from amino acids that, in deficiency states, are converted to glucose and thus become useful to produce energy. In prolonged physical activity sessions, branched amino acids therefore facilitate the production of energy in phases of deficiency.  


+Watt advices

Recommended intake: 5 capsules / 5 g before and after physical activity.