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What Are Amino Acids Used for in Humans?

written by: Teresa Martin•edited by: Diana Cooper•updated: 3/14/2011

What are amino acids? Amino acids are the building blocks that make the body work well. Absence of certain amino acids inhibit areas including fat metabolism and brain function as well as other disorders.

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    Amino Acids - The Building Blocks of Protein

    The body is amazing in its structure and composition. It's built cell by cell, with each cell defined by it's job. Liver, kidney, heart, skin, brain and muscle are made of individual cells. The life and death of cells occurs with regularity, yet the body and each tissue and organ continues to function unless interfered with by disease.

    How does this cycle of growth and continual productivity occur? It occurs through a well oiled machine dependent on proper nutrition, clean oxygen and plenty of fluids. While this may be a simplistic representation, within these elements and substances come the building blocks for protein which are involved in the production of hormones, muscle tissue and other types of cells.

    These building blocks are proteins which are formed from amino acids. So exactly what are amino acids? There are 20 known amino acids; some of the most common are leucine, lysine and glycine. Most of the amino acids are produced by the body, however there are some that must be ingested through the food we eat, such as phenylalanine, valine and tryptophan. These are called essential amino acids which can only be found through eating certain types of food.

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    Peptides, Polypeptides and Protein

    For a healthy body, protein is essential. Protein is needed in the repair and rejuvenation of tissues and cells, the production of enzymes and hormones. Protein makes for strong muscles both smooth and striated. It allows for the transport of nutrients and fluids and provides sustainable energy. In order for adequate amounts of protein to exist to provide for all of these needs all essential building blocks must be present.

    What are amino acids and how do these combine to form proteins? Amino acids come together to form simple structures called peptides. Peptides combine to form polypeptides, which are many peptides joined together by various types of bonds. Polypeptides can be classified by their complexity; they can be simple sequences or multi-dimensional units coming together to form a complex protein. Whether simple or complex, proteins are built from amino acids.

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    Common Diseases from Amino Acid Deficiency

    Diseases or metabolic disorders can result from deficiencies in amino acids themselves, but are more commonly a result of deficiencies in nutrients needed to produce an amino acid, or enzymes needed to use the amino acid.

    One of the common disorders is PKU (phenylketonuria) resulting from a deficiency of the enzyme that breaks down phenylalanine. In the absence of this enzyme there is an increase of phenylalanine in the bloodstream which affects the brain and can lead to mental impairment. This condition is easily diagnosed by a PKU test done in most hospitals and medical facilities in developed countries. The condition is easily treated through a diet low in phenylalanine.

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    Carnitine Deficiency

    Carnitine deficiency can result from a decrease in vitamins B1, B6, C and amino acids lycine and methionine which are required in the production of carnitine. This is a naturally occurring amino acid in the body. Under conditions of decreased vitamins there may be decreased levels of carnitine which are involved in fat transport from fat cells to muscle cells. This is important in fat utilization for energy.

    Effective carnitine production can result in weight loss as well as protecting the body against diabetes by increasing fat metabolism. This may be a factor in preventing heart disease by lowering triglyceride levels in the blood.

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    Georgetown University: