The ABCs of BCAAs

With the asphalt finally dry and the sun setting later and later, excitement is at its peak and we all dream of leaving the office early to burn off some energy on our two-wheeled steeds. We set ourselves fitness goals for the summer and even find ourselves wanting to give it our all to emulate the lives of professional cyclists...

All solutions seem to be considered in order to achieve these performance goals. Listening closely to new trends or those that are sticking around, we see that BCAA supplements stand out from the crowd by promising champion-level performance. 

What are BCAAs?

BCAAs ( branched-chain amino acids) refer to a combination of three essential amino acids that the body cannot synthesize on its own: leucine, isoleucine, and valine. (A quick aside for those who are confused: amino acids are the building blocks of proteins, which are used, among other things, to build our muscle fibers.) Of the nine essential amino acids, these three can only be absorbed through food, either in the form of supplements or food. 

These threebranched-chain compounds have become popular for their ergogenic potential during exercise, i.e., their ability to improve muscle performance. Mainly consumed by athletes who train for muscle strength (at the gym, for example), BCAAs are now gaining ground among endurance athletes, who see them as a potential way to improve their performance, use more fatty acids during exercise, and reduce fatigue. Real effects or placebo effect? 

Less fatigue?

If there is one universal goal among endurance athletes, it is to go faster while using as little energy as possible. Becoming a better version of yourself, gradually observing the effect of diligent training on your pedaling... But seeing a clear improvement often takes a long time and requires rigorous training, a healthy lifestyle, and, above all, monastic consistency. So it's no surprise that we're tempted by products that could mimic these daily efforts and "give" us a few extra watts for the same amount of sweat...

It is believed that BCAAs can reduce the onset of muscle fatigue by blocking the increased use of tryptophan in the brain, which would decrease the production of serotonin, the substance responsible for the feeling of fatigue (see Figure 1). 

However, it would appear that the actual effects observed remain relatively mixed. In a randomized double-blind study conducted on endurance athletes, it was shown that although BCAA supplementation significantly reduces tryptophan utilization during exercise (8-12%), no effect was observed in reducing the onset of fatigue.

Another study looked at BCAA supplementation in a marathon event. The findings? "Slow" runners (> 3:05) saw a slight improvement in their performance and felt less mental fatigue when the supplement was consumed during the race. However, no difference was observed in "fast" runners.

Thus, performance could be slightly improved in endurance events and for less experienced athletes. However, it should be noted that studies on the subject lack sufficient statistical power to be generalized to all athletes, and that the potential effects could vary considerably depending on each individual's athletic and genetic profile. In addition, the dose chosen remains important, as does the timing of its administration.

Energy management

Another hot topic among athletes is becoming more efficient in how they use energy during exercise. How can we conserve our glycogen and even replace glucose with other energy substrates, such as lipids? It seems that BCAAs may have a slight effect in this regard.

Recently, a crossover study examined this phenomenon in seven elite athletes. The athletes in the intervention group consumed a 300 mg BCAA supplement for three consecutive days. On day 2 of the experiment, they underwent aerobic exercise leading to near depletion of their glucose reserves, then repeated the experiment on day 3. Various biochemical parameters were measured, such as lactate, ketones, and plasma glucose. The results show that those receiving a BCAA supplement used less oxygen in the fatigue test and ended up with higher plasma glucose levels than athletes without supplements. They also made better use of lipids during exercise and were significantly less fatigued after exercise. Once again, these results remain mixed in terms of their relevance to the general population.

Relevant in certain cases

During prolonged exercise, BCAAs can therefore help reduce muscle fatigue and become an alternative source of energy to muscle glycogen. By acting on the brain's use of tryptophan, they may also have a potential effect on reducing neuromuscular fatigue and thus improving overall performance.

However, it does not seem essential to purchase them at any cost, considering their mixed effects on exercise. Depending on the context and your athletic goals, this supplement could be either relevant or a waste of money. For those who still want to try BCAA supplements, I suggest testing them out and seeing if, with the recommended dosage, you notice any real effects on your performance. Particularly effective during long-term aerobic exercise, they can be consumed at a rate of about 5 g immediately before exercise, then the same amount every hour, in combination with carbohydrates.

It should be noted that various foods also provide good doses of BCAAs (see Table 1), and that for more recreational athletes, a good intake of varied proteins provides sufficient amounts of BCAAs. Other strategies can also help reduce fatigue during exercise and improve your performance, such as consuming at least 30 g of carbohydrates per hour during exercise, recovering properly after intense activity, and maintaining a consistent pace during training.

Finally, don't forget that it's still vitamin P (pleasure) that will help you keep up the pace, even on days when your legs aren't cooperating...

Figure 1

Table 1: Foods rich in BCAAs

 

References

1. Meeusen, R., et al., "Central fatigue: the serotonin hypothesis and beyond," Sports Med, 2006. vol. 36, no. 10, pp. 881-909.

2. Van Hall, G., et al., "Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance," The Journal of Physiology, 1995, vol. 486, no. 3, pp. 789-794.

3. Blomstrand, E., et al., "Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise," Acta Physiologica, 1997, vol. 159, no. 1, pp. 41-49.

4. Gualano, A., et al., "Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion," The Journal of Sports Medicine and Physical Fitness, 2011, vol. 51, no . 1, pp. 82-87.