Branched Chain Amino Acids - Leucine, Isoleucine, and Valine

Among the most beneficial and effective supplements in any sports nutrition program are branched chain amino acids. These are the essential aminos leucine, isoleucine, and valine.

Although these supplements have been around for a long time and the scientific understanding in the exercise performance benefits of BCAA supplementation is rich many people don't know exactly how they exert their effects or how and when to use them properly.

You probably know that amino acids are the building blocks of protein. When you eat a protein food, it gets digested in the stomach and intestine into individual amino acids and short chains of amino acids that are small enough to be absorbed into the bloodstream. These amino acids have far reaching effects in the body from building and repairing tissues, to producing chemicals that enable our brains to function optimally.

What Is The Difference Between Essential and Non-Essential Amino Acids?
Essential amino acids cannot be made by the body. You must get them from complete protein foods or combinations of incomplete vegetable foods. There are 9 essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, tryptophan, and valine. Your body can make non-essential amino acids by itself from vitamins and other amino acids.

The term "non-essential" can be misleading since all amino acids are essential for proper metabolism and certain non-essential amino acids, such as glutamine, become very essential during illness or trauma. The 13 non-essential amino acids are alanine, arginine, aspartic acid, cysteine, cystine, glutamic acid, glutamine, glycine, hydroxyproline, proline, serine, & tyrosine.

The essential branched chain amino acids (BCAA's) are of special importance for athletes because they are metabolized in the muscle, rather than in the liver. Here's how this works: After digestion, once protein is broken down into individual amino acids these aminos can either be used to build new proteins or be burned as fuel to produce energy.

The BCAAs are distributed to the various tissues of the body via the systemic circulation. The BCAAs appear to be preferentially taken up by skeletal muscle, where they undergo similar catabolic reactions to those described above. Skeletal muscle appears to be the major site of both BCAA transamination and oxidation in humans. BCAAs are also taken up by other organs, particularly the brain and kidney, where they also undergo oxidation.

Where are they found?
Dairy products and red meat contain the greatest amounts of BCAAs, although they are present in all protein-containing foods. Whey protein and egg protein supplements are other sources of BCAAs.

Why do you need them?
During periods of physical stress, such as intense weight lifting and running, the body can enter a catabolic state - that is a state in which muscle tissue is broken down. When this happens, supplementing with BCAAs - especially leucine and its derivatives ketoisocaproate (KIC) and hydroxymethylbutyrate (HMB) is very beneficial in reducing protein breakdown.