|If your are competing in endurance sports BCAA supplements may be more than useless, they may be detrimental.|
In the corresponding experiment, the scientists from Sao Paulo aimed to evaluate effects of the use of supplementation with leucine or a mixture of BCAAs in trained rats submitted to an exercise-induced protocol of glycogen depletion.
Furthermore, Campos-Ferraz et al. attempted to investigate muscle and liver biochemical parameters that were not performed in the studies in order to elucidate the role of BCAAs in glycogen depletion. In that, the scientists' hypothesis was "that the mixture of BCAAs supplementation would impair performance because they would be used mostly in muscle to yield acetyl-CoA, reducing the activity
of the glucose-alanine cycle and thus gluconeogenesis in liver from amino acids, whereas leucine alone could feature the opposite effect in this experimental model" (Campos-Ferraz. 2013).
Obviously, this hypothesis did already imply that the lack of hepatic neogenesis in response to BCAA supplementation may blunt the endurance performance of the 8 wk old rodents that were used as "subjects" in the study at hand.
|Table 1: Swimming training protocol | BW = body weight (Campos-Ferraz. 2013).|
In human terms the 166mg/kg would be approximately 2.0-2.5g depending on the individuals body weight. Significantly less than many people consume before and after their workouts, but enough to elucidate significant performance relevant effects. With differences between the placebo and supplementation arms and differences between the BCAA and leucine arms of the study.
Suggested Read: "True or False? Intra-Workout BCAA Supplements Are Useful Only For Those Who Produce, Import and Sell Them?" If you go by the results of a 2001 study by Blomstrand et al., which is actually the only study to investigate the effect of BCAA intake on the leg exchange of amino acids along with the change in their muscle concentration during exercise and a 2-h recovery period, it would appear as if the claim that "Intra-Workout BCAA Supplements Are Useful Only For Those Who Produce, Import and Sell Them" was true. Find out if it is or not in this SV Classic!
|Figure 2: Liver glycogen degradation (A); liver glycogen content (B); muscle glycogen degradation (C); muscle glycogen content (D) in placebo (PLA), the mixture of BCAAs, and leucine (LEU) groups (Campos-Ferraz. 2013).|
At first this may be surprising, but eventually the data in Figure 2 explains it all. The inhibition of muscle glycogen degradation by BCAAs that is often advertised as one of the most significant benefits of BCAA supplements will turn against you, when you work out to exhaustion, because it reduces availability of glucose and thus increases the dependence on alternative fuel sources from the TCA cycle - a fact that is evidenced by the increases in muscle citrate content and malate content, the scientists observed in the BCAA group.
- Campos-Ferraz, Patricia L., et al. "Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats." Nutrition 29.11 (2013): 1388-1394.
- Elango, Rajavel, Ronald O. Ball, and Paul B. Pencharz. "Indicator amino acid oxidation: concept and application." The Journal of nutrition 138.2 (2008): 243-246.
- Young, Vernon R., Dennis M. Bier, and Peter L. Pellett. "A theoretical basis for increasing current estimates of the amino acid requirements in adult man, with experimental support." The American journal of clinical nutrition 50.1 (1989): 80-92.