Leucine, isoleucine and valine are a group of three essential amino acids known as branched-chain amino acids (BCAA). Essential amino acids – like BCAA’s – are classified as such because the body cannot make them on its own and therefore the essential aminos must be taken in from the diet. BCAA’s make up about one-third of your total muscle protein pool, making them key players in an athletes nutritional arsenal. New clinical research is uncovering exactly why BCAA’s are so important for building lean muscle mass and keeping athletes healthy. In particular, Leucine is showing the greatest potential as the ‘all-star’ of the BCAA group, due in part to its higher oxidation rate or overall utilization by the muscles.

Scientific studies have consistently shown significant decreases in blood levels of leucine following aerobic (11 to 33%), anaerobic lactic (5 to 8%) and strength training (30%) sessions. A recent Italian review study in the Journal of Sports Medicine and Physical Fitness recommended that the current dietary intake of leucine be increased from 14 mg/kg bodyweight/day to a minimum of 45 mg/kg bodyweight/day for sedentary individuals, and even higher doses for those participating in intensive training in order to optimize rates of protein synthesis. The leucine content of a standard serving of protein typically varies between 5 and 10%, and supplementation with BCAA has many positive benefits for athletes. BCAA can dramatically improve athletic performance by increasing exercise capacity, increasing muscular power and endurance, reducing post-exercise soreness and improving immune function.

A Japanese study in 2009 examined the effects of BCAA supplementation on lactate threshold, a measure of exercise capacity. The subjects who consumed a BCAA drink with high leucine content had higher oxygen consumption (VO2) and workload levels at lactate threshold, commonly considered the best marker for aerobic fitness. These results suggest that BCAA supplementation is an effective method to increase exercise capacity and endurance. Improved exercise capacity for athletes translates into better performance during games or improved performance during training, which leads to personal bests during competition. Another study performed in Australian in 2006 examined the effects of leucine supplementation on power production in canoeists. Thirteen competitive outrigger canoeists were divided into two groups, half taking a leucine supplement and half placebo. Researchers results showed that those subjects consuming the Leucine supplement dramatically increased muscular power production after 6-weeks of supplementation compared to the placebo. This is a profound finding! Muscular power is the ‘holy grail’ of athletic success. All top strength coaches will tell you that what translates best to success on the playing field is the capacity to increase an athlete’s power production during training.

BCAA’s not only help improve exercise endurance and muscular power, they actually help minimize muscular damage after prolonged exercise. A 2007 study at Sacred Heart University in Connecticut showed that lactate dehydrogenase levels – a marker for muscular damage – was significantly reduced with supplementation of BCAA’s. Lactate dehydrogenase (LDH) levels increase after intense training bouts and if levels remain elevated it can easily inhibit an athletes capacity to train or perform. Leucine’s ability to reduce LDH is a powerful benefit that can allow athletes to train hard – or perform two a day training sessions – and mitigate the effects of muscular cell damage. In 2009, a Japanese study examined the effects of BCAA supplementation on muscle soreness, muscle damage, and inflammation during intensive training. Twelve subjects participated in the study and the intervention group receiving BCAA supplementation showed significantly reduced muscle soreness and fatigue sensation compared to placebo during their training period. The authors concluded that BCAA supplementation during an intensive training program effectively reduces the muscle soreness and fatigue sensation. Again, this is a tremendously valuable benefit from supplementation, as athletes now compete and train 365 days a year, with little or no off-season, which takes its toll on working muscles and performance.

It is well-documented in scientific journals that athletes and active people often have lower immunity due to their intense training programs. Researchers are now uncovering that BCAA’s may also have a potent immune system enhancing effect. Italian sports scientists conducted a study in 2008 suggesting that BCAA supplementation not only reduces muscle soreness, but also improves immune function. Participants showed increased plasma glutamine levels, recovered mononuclear cell proliferation, and modified exercise-related cytokine response, all of which are important indicators of improved immune function. Athletes are much more prone to colds and flus than sedentary individuals and therefore any means to promote immunity and prevent lost training or competition days to illness is of primary importance. Therefore, branch-chain aminos will not only help you increase your muscular power output and endurance, they will also boost your immune system to keep you fit and healthy!

Supplementation with optimal amounts of Leucine and BCAA’s, as found in NSM’s Athletes Aminos, can help improve your athletic performance, reduce muscle soreness, and increase immune function. Optimal intake will allow you to achieve all your performance goals and personal bests!

Dr. Marc Bubbs N.D., BSc., CSCS, ART
References
1. Matsumoto K, Koba T. Branched-chain amino acid supplementation increases the lactate threshold during an incremental exercise test in trained individuals. J Nutr Sci Vitaminol (Tokyo) 2009 Feb;55(1):52-8.
2. Greer BK, Woodard JL, et al. Branched-chain amino acid supplementation and indicators of muscle damage after endurance exercise. Int J Sport Nutr Exerc Metab. 2007 Dec;17(6):595-607.
3. Negro M, Giardina S, Marzani B, Maratico F. Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system. J Sport Med Phys 2008 Sep;48(3):347-51.
4. Mero, A. Leucine supplementation and intensive training. Sports Med 1999 Jun;27(6):347-58.
5. Crowe MJ, Weatherson JN, Bowden BF Effects of dietary leucine supplementation on exercise performance. Eur J Appli Physiol 2006 Aug;97(6):664-72. Epub 2005 Oct 29.
6. Matsumoto K et al. Branched-chain amino acid supplementation attenuates muscle soreness, muscle damage and inflammation during an intensive training program. J Sports Med Phys Fitness 2009 Dec;49(4):424-31.