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 from its own internal cellular machinery and therefore these 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. BCAA can dramatically improve athletic performance by increasing exercise capacity, increasing muscular power and endurance, reducing post-exercise soreness and improving immune function. Let's take a closer look.
Performance Benefits of BCAAs
1) Increase Exercise Capacity & Endurance
A recent study 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.
2) Improved Power Production
An Australian study recently investigated 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.
3) Minimize Muscular Damage
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.
4) Reduces Muscular Fatigue
BCAA supplementation can also potentially delay fatigue during exhaustive exercise. A small study found a group of cyclists receiving BCAA supplementation had not only significantly reduced muscle soreness, but also delayed fatigue sensation compared to placebo during training. The authors concluded that BCAA supplementation during an intensive training program may effectively reduce muscle soreness and fatigue sensation. This is potentially a tremendously valuable benefit, 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.
5) Improve Immune Function
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.
Achieving The Right Dose of BCAAs
Research consistently shows 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. As a general rule, aim for approximately a 3g of leucine per shake and remember the leucine content of a standard serving of protein typically varies between 5 and 10%.
If you're looking to increase strength, power and work capacity adding supplemental BCAAs with optimal leucine can upgrade your performance, as well as potentially reducing muscle soreness, and improving immune function.
Dr. Marc Bubbs N.D., CISSN, CSCS
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