Branched Chain Amino Acids (BCAAs)

Review of Branched Chain Amino Acids (BCAAs)

1. Branched Chain Amino Acids (BCAAs) Overview
2. Branched Chain Amino Acids (BCAAs) Benefits
3. Branched Chain Amino Acids (BCAAs) Research
4. Branched Chain Amino Acids (BCAAs) Doseage
5. Branched Chain Amino Acids (BCAAs) References

Branched Chain Amino Acids (BCAAs) Overview

The branched chain amino acids consist of: isoleucine, leucine, and valine.  Branched Chain Amino Acids are essential, as our bodies are unable to manufacture these and they must be consumed in adequate amounts through our diet.  They play an essential role in protein synthesis and muscle building processes and account for more than a third of all of the essential amino acids (EAAs) found within our muscle protein.  In addition to playing an important role in protein synthesis BCAAs can be metabolised aerobically as an additional energy source. The best dietary sources of Branched chain amino acids are red meats and dairy products all though they are found in most protein rich foods. Whey protein concentrate and isolate provide great sources of BCAAs.

Branched Chain Amino Acids (BCAAs) Benefits

Branched Chain Amino Acids have a number of potential benefits for strength and endurance athletes including:

• Improvements in Immune Health and immune function
• Branched chain amino acids can reduce muscle catabolism (muscle breakdown)
• Improve rates of muscle synthesis
• Preservation of muscle glycogen stores
• Improve recovery from exercise and reduced muscle soreness
• Branched chain amino atheltes are beneficial to anyone looking to enhance recovery from aerobic exercise and who wants to reduce muscle breakdown.

Branched Chain Amino Acids (BCAAs) Research

Branched Chain Amino Acids (BCAAs) Reduce Muscle Breakdown and Increase Protein Synthesis

Research has shown that supplementation with branched chain amino acids significantly reduces the rate of muscle breakdown (May and Buse, 1989) and can preserve muscle mass even during extremely demanding physical conditions where there would normally be a net loss of muscle tissue (Schena et al., 1992; Bigard et al., 1996). In fact research has shown that under conditions where there would normally be a loss of muscle protein BCAAs have the potential to actually increase the amount of lean muscle (Schena et al., 1992; Bigard et al., 1996).

Muscle breakdown occurs to the greatest extent during prolonged aerobic exercise, where a significant amount of branched chain amino acids are oxidized within the mitochondria of the working muscle. This can lead to a depletion of branched chain amino acids within the muscle and in turn lead to greater muscle breakdown. Research has shown that the consumption of branched chain amino acids before and after exercise reduces the levels of creatine kinase (CK) - a lower level of CK indicates a reduction in muscle breakdown (Coombes and McNaughton, 2000; Nosaka, 2003). Not surprisingly - given the reduced muscle breakdown - supplementation with branched chain amino acids both before and after exercise appears to increase the rate of recovery, as indicated by reduced muscle soreness (Nosaka, 2003).  

Research is clear that supplementation with branched chain amino acids is one of the best ways to stimulate protein synthesis and reduce muscle breakdown, in fact BCAAs supplementation is as beneficial at stimulating protein synthesis and reducing muscle breakdown, as is the case when the supply of all amino acids is increased (May and Buse, 1989). To maximize the protective effects of BCAAs consider supplementing with additional BCAAs before, during, and after exercise.

Researchers have shown that around 77mg of BCAAs per kg of bodyweight (770mg per 10kg), is sufficient to significant reduce in the amount of muscle breakdown (MacLean et al., 1994).  This equates to around 5g of BCAAs for a 70 kg athlete.

Branched Chain Amino Acids (BCAAs) Doseage

For increased protein synthesis, reduced muscle breakdown, and improved recovery consume 3-5grams of BCAAs 30-40 minutes before exercise, and a further 3-5g within 30minutes of completing exercise. During prolonged exercise (exercise lasting more than 1 hour) consider taking an additional 3-5g during the workout. On non-training consumption of 3-5g of BCAAs, two to three times spread throughout the day, to enhance protein synthesis and reduce muscle breakdown. It should be noted that a typical serving of whey protein concentrate or isolate provides around 5g of BCAAs. There are no reports of any side effects associated with BCAA consumption (Shimomura et al., 2004).

Branched Chain Amino Acids (BCAAs) References

Bassit, R. A., Sawada, L. A., Bacurau, R. F. P., Navarro, F. and Costa Rosa, L. F. B. P. (2000) The effect of BCAA supplementation upon the immune system of triathletes. Medicine and Science in Sports and Exercise. 32, 1214-1219.

Bassit, R. A., Sawada, L. A., Bacurau, R. F., Navarro, F., Martins, E. Jr, Santos, R. V., Caperuto, E. C., Rogeri, P. and Costa Rosa, L. F. (2002) Branched-chain amino acid supplementation and the immune response of long-distance athletes. Nutrition. 18 (5), 376-379.

Bigard, A. X., Lavier, P., Ulmann, L., Legrand, H., Douce, P. and Guezennec, C. Y. (1996) Branched-chain amino acid supplementation during repeated prolonged skiing exercises at altitude. Int J Sport Nutr. 6 (3), 295-306.

Blomstrand, E., Hassmen, P. and Ekblom, B. (1991) Administration of branched-chain amino acids during sustained exercise-effects on performance and on plasma concentration of some amino acids. European Journal of Applied Physiology. 63, 83-88.

Coombes, J. S. and McNaughton, L. R. (2000) Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. J Sports Med Phys Fitness. 40, 240-246.

Kobayashi, r. shimomura, Y., Murakami, T., Nakai, N., Otsuka, M., Arakawa, N., Shimizu, K. and Harris, R. A. (1999) Hepatic branched-chain alpha-keto acid dehydrogenase complex in female rats: activation by exercise and starvation. J Nutr Sci. Vitaminol. 45, 303-309.

May, M. E. and Buse, M. G. (1989) Effects of branched chain amino acids on protein turnover. Diab Metab Rev. 5 (3), 227-245.

MacLean, D. A., Graham, T. E. and Saltin, B. (1994) Branched-chain amino acids augment ammonia metabolism while attenuating protein breakdown during exercise. Am J Physiol. 267, E1010-E1022.

Nosaka, K. (2003) Muscle soreness and amino acids. Training J. 289, 24-28.

Rennie, M. J. (1996) Influence of exercise on protein and amino acid metabolism. In: Handbook of Physiology, Sect 12: Exercise: Regulation and Integration of Multiple Systems (Rowell, L. B. & Shepherd, J. T., eds), Chapter 22. 995-1035. American Physiological Society, Bethesda, MD.

Schena, F., Guerrini, F. and Tregnaghi, P. (1992) Branched-chain amino acid supplementation during trekking at altitude. The effects on loss of body mass, body composition, and muscle power. European Journal of Applied physiology. 65, 394-398.

Shimomura, Y., Murakami, T., Nakai, N., Nagasaki, M. and Harris, R. A. (2004) Exercise Promotes BCAA Catabolism: Effects of BCAA Supplementation on Skeletal Muscle during Exercise. J Nutr. 134, 1583S-1587S.