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What
is Amino Acid?
Why Amino
Acids? How does Amino Acids Work?
Amino Acid Supplements |
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What
is Amino Acid?
Amino acid is the basic chemical subunit
of proteins. Amino acids that are joined together by peptide
bonds (strong chemical links) into a "chain" make
peptides or proteins. A huge number of proteins can be made
by varying the sequence and number of amino acids included
in each chain.
Amino acids are divided into two categories:
essential and nonessential. There are nine essential amino
acids that we must get from food. The remaining nonessential
amino acids are required for life, but if they aren't supplied
by our diets, they can be manufactured by our body's cells.
All of the amino acids are vital to good health. In fact,
a lack of just one amino acid will, over time, cause serious
health problems.
Animal proteins (except for gelatin)
contain all nine of the essential amino acids, as well as
some nonessential ones. Because of this, meat, poultry,
eggs, and milk are commonly referred to as containing "complete"
proteins. Proteins from plant sources, such as vegetables
and grains, are called "incomplete" proteins because
they are deficient in one or more of the essential amino
acids. The exception to this is the soybean, which is nearly
equal to animal protein in amino acid content.
Essential amino acids:
Essential amino acids are histamine, isoleucine, leucine,
lysine, methionine, phenylalanine, threonine, tryptophan,
and valine.
Nonessential amino acids:
Nonessential amino acids are alanine, arginine, asparagine,
aspartic acid, carnitine, cysteine, glutamic acid, glycine,
proline, serine, taurine, and tyrosine.
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Why
Amino Acids? How does Amino Acids Work?
The body requires about 50,000 proteins
to make the cells, tissues, organs, enzymes, hormones, and
other substances necessary for life. These proteins are
made up of amino acids, which can combine in an almost infinite
number of ways. Some proteins, such as oligopeptides (oligo
means "few"), are made up of short amino acid
chains, which are composed of just two or three amino acids.
Most of the neurotransmitters (chemical substances that
send messages to and from the brain) are peptides. Other
proteins are made up of hundreds of amino acids.
How does the body know which amino
acids to link together? Our genetic material (DNA, or deoxyribonucleic
acid) has all the "instructions" the body needs.
DNA, which is located in each body cell, tells the cells
which amino acids to hook together to make whatever protein
is needed, when it's needed, and in the amounts necessary.
Amazingly, after a protein has done its job within the body,
it's broken down by other proteinsrecycled so that the
amino acids can be used again in other combinations. It's
a very complicated, efficient process and an essential one,
not only for humans, but for all species.
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Amino
Acid Supplements
In general, most Americans get more protein
than they need, and therefore get adequate amounts of amino
acids. If you're healthy and eating a varied diet, you probably
don't need amino acid supplements. However, amino acids
may be desirable for therapeutic benefits those beyond general
good health. For example, research suggests that various
amino acids (arginine, carnitine, and taurine) are useful
in the treatment of heart disease, while glutamine is beneficial
for problems of the digestive tract.
There is a danger of the body's amino
acids becoming out of balance if single amino acid supplements
are routinely taken. For those using amino acids longer
than a month, a supplement that provides a variety of amino
acids (sometimes called a "complex") is recommended
to help keep amino acid intake balanced. In addition, when
amino acids are taken for therapeutic benefits, it's wise
to do so under a doctor's supervision, especially if you'll
be taking them longer than a few months. Never exceed the
recommended dose of amino acids, as high doses may be toxic
and cause nausea, vomiting, or diarrhea. Finally, pregnant
women or anyone with liver or kidney disease should talk
to their doctor before taking any amino acid supplements.
L or D?
Amino acid names on supplement
labels are frequently preceded by the letters "L"
or "D." This refers to the chemical form of the
amino acid. Those with the "L" in their name are
the most similar to amino acids in the body, and are therefore
preferable over the "D" forms. |
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