What are Amino Acids?
by Dr. Gary Farr on 14 February 2002
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Types of Amino Acids: Essential Amino Acids (EAAs); Semiessential Amino Acids
What are They? Amino acids are the chemical units or "building blocks," as they are popularly called, that make up {protein} protein. To understand how vital amino acids are, one must understand how essential proteins are to life. It is protein that provides the structure for all living things. Every living organism, from the largest animal to the tinniest microbe, is composed of protein. And in its various forms, protein participates in the vital chemical processes that sustain life.
Proteins are a necessary part of every living cell in the body. Next to water, protein makes up the greatest portion of our body weight. In the human body, protein substances make up the muscles, ligaments, tendons, organs, glands, nails, hair, and many vital body fluids, and are essential for the growth, repair and healing of bones, tissues and cells. The enzymes and hormones that catalyze and regulate all bodily processes are proteins. Proteins help regulate the body's water balance and maintain the proper internal pH. They assist in the exchange of nutrients between the intracellular fluids and the tissues, blood, and lymph. They help provide energy. A deficiency of protein can upset the body's fluid balance, causing edema (water retention). Proteins form the structural basis of chromosomes, through which genetic information is passed from parents to offspring. The genetic "code" contained in each cell's DNA is actually information for how to make that cell's protein.
Each of these individual functions would make the intake of the appropriate level of amino acids a priority, and collectively their roles in the repair and maintenance of a healthy and well running body biosystem make them vital.
Diets that are not balanced or that are high in empty carbohydrates can become protein (and amino acid) deficient. If our diet doesn't supply an adequate amount, the body draws on its own tissue proteins. Because the body can't store amino acids it will break down its own protein structure, including healthy muscle, to meet the need for single amino acids. Most of us assume that we are getting plenty of amino acids from the food we eat, but in reality we may not be. Dr. Eric Braverman, author and researcher at Princeton Brain Bio Center, notes: We often do not realize our need for amino acids, because we are not aware of how busy the human body is. Every second the bone marrow makes 2.5 million red cells. Every four days the lining of the gastrointestinal tract and the blood platelets are replaced Most of the white cells are replaced in ten days. A person has the equivalent of new skin in twenty-four days and bone collagen in thirty years. All this continuous repair work requires amino acids.
Proteins are chains of amino acids linked together. Each individual type of protein is composed of a specific group of amino acids in a specific chemical arrangement. It is the particular amino acids present and the way in which they are linked together in sequence that gives the proteins that make up the various tissues their unique functions and characters. Each protein in the body is tailored for a specific need, proteins are not interchangeable.
The body cannot directly use proteins found in food. The proteins that make the human body are not obtained directly from the diet. Rather, dietary protein is broken down into its constituent amino acids, which the body then uses to build the different specific proteins it needs. Thus, it is the amino acids rather than protein that are the essential nutrients.
In addition to combining to form the body's proteins, some amino acids act as neurotransmitters or as precursors of neurotransmitters, the chemicals that carry information from one nerve cell to another. Certain amino acids are thus necessary for the brain to receive and send messages. Unlike many other substances, neurotransmitters are able to pass though the blood-brain barrier. Because certain amino acids can pass through this barrier, they can be used the brain to communicate with nerve cells elsewhere in the body.
Amino acids also enable vitamins and minerals to perform their jobs properly. Even if vitamins and minerals are absorbed and assimilated the body, they can not be effective unless the necessary amino acids are present. For example, low levels of the amino acid tyrosine may lead to iron deficiency. Deficiency and/or impaired metabolism of the amino acids methionine and taurine has been linked to allergies and autoimmune disorders. Many elderly people suffer from depression or neurological problems that may be associated with deficiencies of the amino acid tyrosine, tryptophan, phenilanine, and histidine, and also of the branched-chain amino acids - valine, isoleucine, and leucine. These are amino acids that can be used to provide energy directly to muscle tissue. High doses of branched-chain amino acids have been used in hospitals to treat people suffering from trauma and infection.
There are approximately twenty-eight commonly known amino acids that are combined in various ways to create 150 or more other intermediates inside the body as well as the more than 40.000 proteins known so far to science. The essential amino acids are those that the body cannot synthesize in sufficient quantities to satisfy the nutritional requirements for good health and that they must be included in the diet. The nine essential amino acids are HISTIDINE, ISOLEUCINE, LEUCINE, LYSINE, METHIONINE, PHENYLALANINE, THREONINE, TRYPTOPHAN and VALINE; their best sources are meat, fish, fowl, eggs and dairy products. In addition, CYSTEINE (cystine) and TYROSINE, sometimes classified as NONESSENTIAL AMINO ACIDS, are now considered semiessential because if the diet contains them (meat, milk, fish, poultry and legumes are good sources), the body can use them in place of two essential amino acids methionine and phenylalanine, respectively to make protein. The nonessential amino acids are ALANINE, ARGININE, ASPARAGINE, ASPARTIC ACID, GLUTAMIC ACID, GLUTAMINE, GLYCINE, PROLINE, SERINE and TAURINE.
The processes of assembling amino acids to make proteins, and of breaking down proteins into individual amino acids for the body's use, are continuous ones. When we need more enzyme proteins, the body produces more enzyme proteins; when we need more cells, the body produces more proteins for cells. These different types of proteins are produced from amino acids as the need arises. Should the body become depleted of its reserve of any of the essential amino acids, it would not be able to produce the proteins that require those amino acids. If even one essential amino acid is missing, the body can not continue proper protein synthesis. This can lead to lack of vital proteins in the body, which can cause problems ranging from indigestion to depression to stunted growth.
How could such a situation occur? More easily than one might think. Many factors can contribute to deficiencies of essential amino acids, even if you eat a very well balanced diet that contains enough protein. Impaired absorption, infection, trauma, stress, drug use, age, and imbalances of other nutrients can all affect the availability of essential amino acids in the body.
Some of the effects of a diet deficient in amino acids include: Reduced energy levels, metabolism, sleeping disorders, chronic fatigue, digestive problems, hair loss and skin ailments, nervous reactions, emotional upset, stress and general poor health. Other possibly life-threatening symptoms of amino acids deficiency include obesity, malnutrition, and buildup of wastes in the bloodstream. All of these effects can be extremely detrimental to an individual's well-being, so a balanced intake of amino acids becomes extremely important.
Because of their essential functions amino acids are vital and it makes good sense to supplement the diet with a quality amino acid complex.
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