As you remember from earlier modules, amino acids are organic chemicals that link together in chains (called poly-peptides) to form proteins. There are about two dozen amino acids in all, and they are all important for human strength, health, and vitality.
Here's an interesting fact: amino acids exist everywhere. They have been found in meteorites which crashed into Earth from outer space, and scientists believe they have discovered evidence of amino acids in a molecular cloud near the center of our Milky Way Galaxy. These amazing building blocks of life exist not only within us--they are spread throughout the universe!
Three amino acids are grouped together under the general term branched chain amino acids (BCAAs). BCAAs are considered essential amino acids because human beings cannot survive unless BCAAs are obtained through diet or supplementation; BCAAs cannot be produced by our bodies.
The three BCAAs are:
You may wonder why these three are viewed as a group. What do they have in common? The answer is that leucine, isoleucine, and valine are chemically unique from their brethren. The molecular structure of BCAAs features a unique branch a single carbon atom bound to more than two other carbon atoms.
BCAA's comprise a large percentage of the essential amino acids in body protein and in our skeletal muscle. On average, approximately one-fifth of our total protein intake is BCAAs.
- Branched Chain Amino Acids are designed to help support protein metabolism in muscle tissue.
- BCAAs can be used for energy in muscle tissue.
- BCAAs are directly involved in protein synthesis at the genetic level.
- BCAAs are the only amino acids metabolized directly in the muscle as opposed to the liver.
- Branched chain amino acids help support muscle nitrogen and a free amino acid pool during exercise.
- BCAAs comprise a large percentage of the amino acid composition of muscle tissue.
The most important feature of the BCAAs is that they are metabolized directly in the muscle. They are the only amino acids not metabolized in the liver. This unique attribute means they can also be used as a source of energy in muscle. For this reason, BCAA supplementation is common among athletes who undergo intense, prolonged exercise.
BCAAs are not only involved in normal protein metabolism; during periods of stress they are required in larger amounts than other amino acids. This may be because they play an important role in slowing protein breakdown and boost protein synthesis at the same time.
Here are some details about the three members of the BCAA team:
- Leucine is necessary for the maintenance of nitrogen balance in adults, and the healthy growth of children and adults. It helps regulate carbohydrate metabolism and regeneration of skin and muscle tissue. Leucine is a nutrient signal which regulates protein synthesis. In skeletal muscle, it stimulates protein synthesis.
- Isoleucine produces various biochemical compounds active in energy production. Like leucine, it helps growth and nitrogen balance, but it also helps form hemoglobin and maintains the body's regular energy metabolism. Importantly, isoleucine is metabolized into muscle tissue, and it is important in protein synthesis.
- Valine is an organic compound which adds to the strength of any proteins with which it combines. Valine is involved with synthesizing glucose in the liver especially during activities without a proper amount of oxygen intake.
Red meat and dairy products generally contain the greatest amounts of dietary BCAAs, although whey protein and egg protein supplements are also good sources.
- Soy flour
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