Branched Chain Amino Acids (BCAAs) are three amino acids: Leucine, Isoleucine, and Valine. These BCAAs are essential nutrients that the body obtains from proteins found in food, especially meat, dairy products, and legumes. Amino Acids are the building blocks of protein and have various functions related to energy production during and after exercise so they are needed in adequate amounts.
You need essential amino acids in your daily diet since your body cannot make them. If you don't get essential amino acids in your diet, proteins break down, resulting in muscle loss and problems with repair. Leucine, isoleucine and valine, the branched-chain amino acids (BCAA), make up about one-third of muscle protein.
Let's take a look at these BCAA amino acids and the role they play within our bodies.
Leucine is critically important in that it is the only Amino Acid that stimulates muscle protein synthesis, so as we age it helps to slow normal age-related degradation of muscle tissue. Instead it supports muscle growth. The fact that Leucine stimulates muscle protein synthesis makes it very important to athletes, body builders, and men and women of all ages that have good exercise and, or workout routines. Leucine has also been shown to enhance and slow mental acuity due to aging.
One particular study examined the effect of 6 weeks of leucine supplementation on a number of physical and performance characteristics in canoeists (Crowe).
This randomised, double blind trial examined the influence of 45mg of leucine per kg of bodyweight (vs 45mg/kg of corn flour placebo) on VO2 max, upper body anaerobic power and time to exhaustion in a 70-75% maximal intensity row.
The results indicated that the group given leucine supplementation had improved upper body power output, reduced rate of perceived exhaustion, and longer exercise time to fatigue (compared to placebo).
Isoleucine is critical to ongoing muscle tissue maintenance and it helps muscles store glycogen to produce energy. It further helps prevent protein deterioration during muscle-demanding sports and, or exercise. It helps to repair, heal, and grow damaged muscle tissue. It also helps to reduce recovery time after workouts and, or strenuous exercise routines.
Valine stimulates protein synthesis directly in muscle tissue, it is considered one of the body’s most important “fuels” used in the building of lean muscle tissue and the enhancement of muscle “reaction”. Valine also helps our bodies maintain the proper nitrogen balance. It also helps to stimulate the central nervous system for ongoing mental acuity and has been known to improve liver functions that may have been degraded by alcohol or drug abuse.
Exercise-induced muscle damage (EIMD) decreases muscle function and causes soreness and discomfort. Branched-chain amino acid (BCAA) supplementation has been shown to increase protein synthesis and decrease muscle protein breakdown, however, the effects of BCAAs on recovery from damaging resistance training are unclear.
A study published in the Journal of the International Society of Sports Nutrition looked at the role BCAAs played to assist in the recovery of muscles post-exercise. BCAA administered before and following damaging resistance exercise reduces indices of muscle damage and accelerates recovery in resistance-trained males. A 20 g/day supplementation regimen administered 7 days prior to (with additional 20 g immediately before and following the damaging exercise) and for 4 days after a damaging bout of eccentric biased exercise reduced soreness and the plasma level of intramuscular enzymes.
Most importantly, BCAA attenuated reductions in muscle function and accelerated recovery post-exercise in a resistance-trained population.