BCAAs (Lucine, Isoleucine & Valine): one of the most popular and frequently used supplements on the market today. We are told they will promote faster recovery, prevent muscle soreness and aid muscle hypertrophy. Often used to hydrate with more pleasure due to its flavouring without understanding the potential for detrimental effects on mood and mental health. Here is what the research says:
The efficacy of a nutritional strategy based on BCAA supplementation and aimed at reducing/preventing muscle damage resulting from high intensity exercise seems to be poor. There is no direct evidence of positive effects of BCAAs on muscle damage (Foure A. 2017).
If only 3 EAAs are consumed, as is the are with consumption of BCAAs, then protein breakdown is the only source of the remaining EAAs required as precursors for muscle protein synthesis. It is therefore theoretically impossible for consumption of only BCAAs to create an anabolic state in which muscle protein synthesis exceeds muscle protein breakdown (Wolfe R. 2017).
BCAA are transported from the blood into the CNS through the blood-brain carried by a large amino acid transporter. This system is saturated at physiological amino acid concentrations, and uptake of BCAA is competitive with respect to uptake of aromatic amino acids. Therefore, an increase in circulating BCAA is predicted to decrease the uptake of AAA into the CNS (Coppola A. 2012).
Tyrosine is the precursor of norepinephrine and dopamine, whereas tryptophan is the precursor of serotonin. Thus, the rate of production of important neurotransmitters may be affected by changes in amino acid concentrations in the blood. This could potentially include serotonin, which regulates a variety of behavioural functions, including mood and appetite regulations. This may explain some of the association between obesity and mood disorders.
Behavioural changes are associated with a significant decrease in the concentration of tryptophan in brain tissues as a consequent decrease in serotonin. Several studies have shown an association of low serotonin levels with the increase in anxious like behaviour (Tanke MA. 2008).
In summary, BCAAs are expensive bullshit.
