Amino Acids - Building blocks of proteins
Amino acids are the principal building blocks of proteins and enzymes. Your body needs amino acids to build proteins, which are complex organic compounds. The basic structure of protein is a chain of amino acids.
The value in ingesting protein (either in the form of food or dietary supplements) is that it is broken down into polypeptides by hydrochloric acid in the stomach and then into amino acids by digestive enzymes in the small intestine. The aminos are then absorbed into the body through the wall of the small intestine. If the wall of the small intestine is in healthy condition, it will not allow anything larger than an individual molecule to pass through it and into the body. It acts as a barrier for undigested organic compounds.
Once the amino acid is inside of the body, the aminos will then dictate how they will be used to build new proteins. The new proteins will then do various functions inside of the body. We will discuss exactly what the functions are later in this article. But first a little background information.
Essential Amino Acids
The body also has the ability to synthesize amino acids. That is to say, the body can make amino acids from scratch. Of the approximately 20 common amino acids, the body can synthesize all except for eight of these. These 8 aminos must be supplied from the outside and are referred to as essential amino acids, because they are essential to sustain life.
The 8 essential amino acids are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
There is a ninth amino acid considered to be essential, in that it is only required from infancy and throughout the childhood years. This amino acid is called histidine. After the body matures into adulthood it ceases to be essential, for the adult body will be able to synthesize histidine on it's own.
Although arginine is considered an essential amino acid, this is true only during the juvenile period in humans. Even so another amino acid, ornithine, can be converted to arginine in the body and therefore serves as a back up supply of arginine for the body to use to build new proteins. Arginine is a very complex amino acid that is often found at the active (or catalytic) site in proteins and enzymes.
Proteins in Your Diet
Protein is the main component of muscles, organs, and glands. Every living cell and all body fluids, except bile and urine, contain protein. The cells of muscles, tendons, and ligaments are maintained with protein. Children and adolescents require protein for growth and development.
Proteins can be broken down into two categories, complete and incomplete proteins. A food product that will supply enough of the essential amino acids is considered to be a complete protein. It is considered to be an incomplete protein if it does not supply enough of the essential amino acids.
In general, sources of complete proteins can be found in all meat and animal products such as beef, chicken, fish, eggs, milk, and other dairy products. Plant proteins on the other hand are either low, incomplete protein or lack one of the essential amino acids and are considered incomplete proteins. Although, plant proteins can be combined to include all of the essential amino acids and form a complete protein. One example of a complete plant protein would be rice and beans. Vegetarian diets are able to get enough protein if they have the proper combination of plant proteins to provide you with the essential amino acids.
A nutritionally balanced diet provides adequate protein. We should point out that there are also certain dangers in diets that are high in meat, as well as high-protein diets which could lead to high cholesterol or put undue strain on the kidneys. The amounts of recommended proteins depends upon numerous things such as age, weight, and other factors and is beyond the scope of this article. We recommend that you consult with a qualified dietician or your physician in regards to proteins in the diet.