The branch chain amino acids (BCAA) are a select group of essential amino acids; leucine, isoleucine, and valine. The body cannot synthesize them; they must be provided in the diet in abundance. In recent years the BCAAs have received an incredible amount of attention from sports scientists, and this new focus appears to be well deserved.
More so than any other amino acids (the building blocks of structures within the body) they play a number of indispensable roles in muscle metabolism, particularly during and after intense exercise. In fact, based on the evidence I’ve examined, I’d go so far as to say that the presence (or absence) of the BCAAs can profoundly affect your performance, recovery, and results from exercise training.
Most athletes know that the BCAAs are indispensable to the synthesis of new proteins. They are also required to form all biomolecules that construct hair and nails through to digestive enzymes (and everything in between). However, the BCAA are unique as they can also be utilized extensively as a source of energy, particularly during high-intensity exercise.1,2
The BCAAs enter this pathway via the removal of an amino group by a transaminase, which is then fed into the urea cycle. The other “product” of this transamidation is a keto acid that enters the aerobic energy producing pathway (the citric acid cycle). The BCAAs are glucogenic, which means they are easily converted into glucose, through the process of gluconeogenesis.3 This tends to be the dominant fate of the BCAAs during intense exercise, particularly during calorie-restricted diets.
If you’re trying to build muscle, this is bad news as the BCAAs are also the most potent amino acids that ignite muscle protein synthesis, which is the underlying mechanism of cellular recovery and gains in muscle mass.4
To achieve their physique goals most people know that intense exercise training is vital. Calorie-restriction is also crucial. Therefore, it’s easy to see how the BCAAs end up in a constant state of “tug-o-war” between providing energy to fuel intense workouts and the building blocks that are indispensable to muscle repair and anabolism (growth).4,5
However, as if these two processes are not important enough, the BCAAs also provide at least two other exclusive functions that are imperative to hard-training athletes.
The BCAA-Glutamine Link
The BCAAs are utilized exclusively to synthesize glutamine; the amino acid that is the primary fuel of the immune system.6 However, the amount of glutamine within muscle governs protein synthesis rates and muscle mass, as well as supplies precursors for antioxidant protection.7 Glutamine, plays a role in maintaining healthy insulin secretion and also regulates the expression of many genes related to metabolism, signal transduction, immune defense and cellular repair.8
Supplementation is one step to meeting your body’s extraordinary needs during intense training but don’t forget that the BCAAs supply up to 70% of your body’s daily glutamine requirements. And these requirements are relentless. Periods of intense metabolic stress such as exercise training and dieting can easily outstrip the body’s synthesis capabilities for glutamine. The BCAAs are the only amino acids that can be used to synthesize glutamine, and as I mentioned before, they meet up to 70% of your body’s daily glutamine requirements.
Metabolic estimates have indicated that without this constant synthesis of glutamine from the BCAAs, the human body would run out of glutamine in 7 hours or less!9
CNS Fatigue Blocker
Most athletes are not aware that the BCAAs have a direct influence on exercise performance.10 A number of studies have directly linked supplementation to the prevention of central nervous system (CNS) fatigue.10-14
Supplementation can prevent CNS fatigue by competing with free-tryptophan for uptake from the plasma into the brain. Studies report that supplementation can prevent CNS fatigue in athletes using a 2-6 gram dose per hour of exercise. Interestingly, this amount was also shown to significantly decrease perceived exertion and increased endurance performance.
One recent study has shown that supplementation with leucine (approximately 3.6 grams/day for an 80kg individual) increased plasma BCAA concentrations and improved upper body power output and exercise time to exhaustion in a group of rowers (outrigger canoeists).10
Under a variety of circumstances, in well-controlled studies supplementation is shown to improve exercise performance. This places the BCAAs in an elite category of research-proven ergogenic aids; nutrients shown in research to enhance exercise performance. All athletes can strategically supplement to help prevent CNS fatigue and boost performance during intense activity. I recommend one serving of BCAA 4500 within the hour before and another serving midway through any workout that lasts longer than 30 minutes. Bodybuilders and strength athletes may want to take this serving half-way through their workouts; it can be a quick way to help prevent the accumulation of tryptophan and CNS fatigue.
For people who like to participate in an intense exercise of prolonged duration such as triathlons, cycling, mountain biking, surfing or team-based events such as football, etc., I recommend a serving every 40-60 minutes of activity. I’ve found this strategy particularly useful in delaying fatigue towards the back-end of the session. It prevents performance decreases during prolonged events.
Another significant benefit is that the BCAA have a very positive effect on body composition. Aside from their potent anabolic effect on muscle, for reasons that are not yet clear to scientists, a high intake of BCAAs seems to enhance fat loss during weight training exercise.15,16
Scientific evidence shows that BCAA supplementation can provide a number of significant benefits under a variety of circumstances. These advantages range from delaying central nervous system fatigue to reducing muscle damage and sparing valuable muscle fuel but also accelerating recovery and boosting immunity after intense exercise.
No matter what your sport, BCAA 4500 is the purest branched-chain amino acid supplement you’ll find anywhere and is an essential addition to your supplementation arsenal.
1. Am J Physiol Endocrinol Metab 249:E137–E144, 1985.
2. Exercise & Sport Science Rev.26:287-314. 1998.
3. J Nutr 130 (4S Suppl): 988S-90S, 2000.
4. J Nutr. 2006 Jan;136(1 Suppl):264S-8S.
5. Can J Appl Physiol 27:646–663, 2002.
6. FASEB J.10;829-837. 1996.
7. J Cell Physiol 204: 392-401, 2005.
8. Front Biosci. 1;12:344-57, 2007.
9. Sports Med. 21; 80-97, 1996.
10. European Journal of Applied Physiology, 97; 664-672, 2007.
11. Med Sci Sports Exerc 27: S149, 1995.
12. Acta Physiol Scand 159:41–49, 1997.
13. Med Sci Sports Exerc 30:83–91, 1998.
14. Eur J Appl Physiol Occup Physiol 63:83–88, 1991.
15. Amino Acids 25:85–94, 2003.
16. Int J Sports Med. 18;47-55, 1997.