Protein supplementation is extremely common in both endurance and strength training athletes. Proteins, however, are composed of individual amino acids all of which have different roles in the body. Some of these amino acids are considered essential, which means that they cannot be produced by the body and must come from our diet and others are non-essential, which means that the body can make them provided it has the necessary components.
The branched chain amino acids (BCAAs) are a group of three essential amino acids – leucine, isoleucine and valine. Individual and combinations of select amino acids are marketed to athletes and are available for purchase including formulations of the BCAAs. What are the proposed benefits of BCAA supplementation and are these claims supported by the research?
Exercise often results in muscle damage. This “damage” stimulates muscle growth and regeneration; however, if it occurs chronically it can inhibit recovery. Physically, this means your muscles feel weak and sore. It has been suggested that consuming BCAAs prior to exercise can have a prophylactic effect thus improving recovery of damaged muscles and reducing muscle soreness. If meat, dairy products, and legumes are rich dietary sources of BCAAs, why supplements?
It is known that the muscles contain significant amounts of BCAAs and that these BCAAs are broken down during exercise. It is also known that the BCAAs have several roles in the body as it relates to athletes including: regulating protein breakdown and the production of new proteins. Consequently, it has been hypothesized that BCAA supplements are beneficial in exercise and sport (1). Several studies have been conducted, however, before we present the results we want to highlight that in most cases the samples sizes are quite small, the people they choose are not always representative of the athletic population, dietary intakes are rarely well-controlled for and the studies are of short duration. Keeping those limitations in mind; read on.
Consuming BCAAs prior to resistance training has been found to reduce delayed onset muscle soreness. A recent review of the evidence is available by da Luz et al. (2), however, typically no improvements in muscle function were found in the short term studies available. One longer term study (still only 4 weeks) did find increased levels of testosterone and less muscle damage with BCAAs supplementation (3) but further research is required to see if long term supplementation can result in improvements in performance. Additional long term studies are also required to corroborate these results.
To enhance recovery it is often recommended that endurance athletes consume carbohydrates and protein in combination to maximize glycogen production; glycogen is the body’s fuel source as it can be broken down into glucose. The recovery process has two distinct phases (4):
- an insulin dependent phase that occurs within the first hour followed by
- an insulin independent phase that can last for several hours.
Consuming a protein-leucine combination with carbohydrates and fats (this sounds a lot like regular food…) in the one to three hours after exercise did minimize muscle damage in male cyclists over 6 days of repeated exercise, however, they didn’t report any significant improvements in performance (5). Conversely, there may be a role for BCAAs supplementation in athletes required to compete in multi-day events as Gualaon et al. (6) found BCAAs reduced fatigue and caused the body to preferentially burn fat after the participants underwent a 3-day exercise protocol that depleted their glycogen stores. Furthermore, BCAAs supplements in long distance runners reduced muscle soreness and fatigue and the authors concluded that the effects are linked to a decrease in muscle damage and inflammation (7). The same group also reported that BCAAs consumed for one week increased workload and VO2 max in a cycling-to-exhaustion exercise test (8).
Interestingly, it may be that BCAA supplementation benefits the brain more than the muscles. There is some evidence to suggest that BCAAs could improve reaction time in soccer players (9) and reduce ratings of perceived exertion (10).
No Baloney’s Advice. Overall, it appears that BCAAs may reduce muscle soreness caused by exercising, and certainly supplementation increases the amount of BCAAs available. The effects on performance are still unclear and the benefits of BCAA supplementation versus traditional food sources are uncertain.
What is interesting about these studies is that many of them used the ingestion of the BCAA PRIOR to exercise, whereas, often the focus has been on ingesting protein AFTER exercise in the recovery window. Finally, if you decide upon supplementation, be sure to consume a product that is approved for athletes and is of high quality and free of contamination.
- Shimomura Y, Murakami T, Nakai N, Nagasaki M, Harris RA. Exercise promotes BCAA catabolism: effects of BCAA supplementation on skeletal muscle during exercise. J Nutr 2004; 134:1583S-1587S.
- da Luz CR et al. Potential therapeutic effects of branched-chain amino acids supplementation on resistance exercise-based muscle damage in humans. J Int Soc Sports Nutr 2011; 8:23 [epub ahead of print].
- Sharp CP, Pearson DR. Amino acid supplements and recovery from high-intensity resistance training. J Strength Cond Res 2010; 4:1125-30.
- Jang TR, Wu CL, Chang CM, Hung W, Fang SH, Chang CK. Effects of carbohydrate, branched-chain amino acids, and arginine in recovery period on the subsequent performance in wrestlers. J Int Soc Sports Nutr 2011; 22; 8:21 [epub ahead of print].
- Nelson AR et al. A protein-leucine supplement increases branched-chain amino acid and nitrogen turnover but not performance. Med Sci Sports Exerc 2012; 44:57-68.
- Gualano, AB et al. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness 2011; 51:82-8.
- Matsumoto K, Koba T, Hamada K, Sakurai M, Higuchi T, Miyata H. Branched-chain amino acid supplementation attenuates muscle soreness, muscle damage and inflammation during an intensive training program. J Sports Med Phys Fitness 2009; 49:424-31.
- Matsumoto K, Koba T, Hamada K, Tsujimoto H, Mitsuzono R. Branched-chain amino acid supplementation increases the lactate threshold during an incremental exercise test in trained individuals. J Nutr Sci Vitaminol (Tokyo) 2009; 55:52-8.
- Wiśnik P, Chmura J, Ziemba AW, Mikulski T, Nazar K. The effect of branched chain amino acids on psychomotor performance during treadmill exercise of changing intensity simulating a soccer game. Appl Physiol Nutr Metab 2011; 36:856-62.
- Greer BK, White JP, Arguello EM, Haymes EM. Branched-chain amino acid supplementation lowers perceived exertion but does not affect performance in untrained males. J Strength Cond Res 2011; 25:539-44.