It has long been established that protein is an essential nutrient that needs to be obtained from our diets. The ultimate value of a protein source is its amino acid composition. Basically, a protein molecule is a long chain of amino acids linked by peptide bonds (i.e., an amino acid linked to another amino acid). Hundreds of different amino acids exist in nature; however, only twenty-two are typically found as components in human peptides or proteins. Once digested and absorbed, these amino acids play central roles as building blocks of proteins and as intermediates in metabolism, thereby controlling virtually all cellular process and reactions in living cells.
Twenty-two amino acids have been identified that are naturally incorporated into polypeptides (i.e., long chain of amino acids) and are called proteinogenic (used in the production of protein). Of the twenty-two amino acids, eight are labelled “essential” amino acids because the human body cannot synthesize them from other compounds, so they must be obtained from our diet. The remaining fourteen amino acids are “non-essential” because they can be made in the body. Failure to obtain enough of even one of the essential amino acids results in degradation of the body’s proteins (e.g., muscle tissue).
The branched chain amino acids leucine, isoleucine, and valine are classified among the essential amino acids. They are very important for active individuals, bodybuilders, and professional athletes since they influence various aspects of muscle metabolism. The “branched chain” designation refers to their unique chemical structure. The combination of these three BCAAs makes up approximately 1/3 of skeletal muscle in the human body. The body requires higher amounts of BCAAs during and following exercise as they are taken up directly by the skeletal muscles versus other amino acids that are first metabolized through the liver. BCAAs are unique in that they can be used to either build new proteins or be burned as fuel to produce energy.
During exercise, increased oxidation of the BCAAs is generally recognized as the signal to the body to stop protein synthesis in the muscles. Consuming BCAAs before or after exercise can reduce protein breakdown, increase protein synthesis, and stimulate the release of insulin. Insulin is an anabolic hormone usually associated with building various energy molecules in the body (e.g., glycogen and triglycerides) and with preventing the breakdown of muscle following periods of physical stress (e.g., exercise), thereby preserving muscle mass. Less muscle damage and less soreness mean faster recovery and a quicker return to training.
Leucine has recently been shown to have its own anabolic (i.e., muscle-building) abilities by influencing various signalling cascades and chemical signals that activate protein synthesis. Through phosphyorylaton of mammalian target of rapamycin (mTor ), a key regulator of cell growth and protein synthesis, leucine, along with the other two BCAAs, transforms the body into a muscle-building machine. In simple terms, the body is switched into an anabolic state using available amino acids to build hard, dense muscle. To obtain the greatest benefit from BCAA supplements, you must ensure that you get enough protein from your diet to support an increased ability to grow.
Bodybuilders, athletes, weekend warriors who weight train regularly, and endurance athletes who regularly compete in aerobic events such as running, cycling, or swimming will benefit from BCAA supplementation. Supplementation of BCAAs will help meet the increased demand the body requires under times of stress. BCAAs can enhance energy levels, build muscle, and speed recovery under a variety of metabolic conditions. Aside from playing an important role in protein synthesis, the BCAAs provide extra energy during heavy lifting, help spare muscle tissue, and fight mental brain drain as you battle through a workout. BCAAs can be taken at anytime during the day, preferably on an empty stomach to avoid competition for absorption with other amino acids; however, the most beneficial times to take the BCAAs are directly before or just after training.