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What Is Amino Acid?
The body uses chemical substances called amino acids to build the exact type of protein it needs. There are two types: essential and nonessential. While the body must get the essential amino acids from foods, it can manufacture the nonessential amino acids on its own if the diet is lacking in them.
Of the approximately 80 amino acids found in nature, only 20 are necessary for proper human growth and function. Not only do they help make neurotransmitters--the chemicals that convey messages in the brain--they also help produce hormones such as insulin; enzymes that activate bodily functions; and certain types of body fluids. In addition, they are essential for the repair and maintenance of organs, glands, muscles, tendons, ligaments, skin, hair, and nails.
An amino acid deficiency is usually caused by a diet that is low in protein, although the level of certain acids can also drop in the presence of trauma, infection, medication effects, stress, aging, and chemical imbalances within the body.
A blood test can detect a deficiency, which can be corrected by taking amino acid supplements. In addition, certain amino acids taken in supplement form may aid in fighting heart disease, lowering blood pressure, protecting against stroke, and alleviating intermittent claudication (a type of leg pain caused by blocked arteries in the legs). They may also help in treating cancer, reducing sugar cravings, building immunity, and protecting the body in various other ways.
Look for amino acid supplements prefaced by the letter L (such as L-arginine). These are more similar to the amino acids in the body than are amino acid supplements prefaced by the letter D. (One exception is D-L phenylalanine, which treats chronic pain.)
The essential amino acids are histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan, and valine.
The nonessential amino acids are alanine, aspartic acid, arginine, citrulline, glutamic acid, glycine, hydroxyglumatic acid, hydroxyproline, norleucine, proline, and serine.
If you take an individual amino acid supplement for longer than one month, take it with an amino acid complex that contains a variety of amino acids. This will ensure that you get a proper balance of all the amino acids. To be safe, never take individual amino acid supplements for longer than three months unless you are under the direction of a doctor familiar with their use. Solviolence.org
BIOEFFICACY OR NUTRITIONAL UTILIZATION
The relative bioefficacy of alternative commercial methionine products has been controversial for many
years. The controversy in basic terms (and at the risk of oversimplification) has been as follows: major
producers of DL-methionine claim that (1) the bioefficacy of DL-methionine hydroxy analog, free acid, is
10-25% lower than that of DL-methionine on an equimolar basis and (2) the bioefficacy of DLmethionine
hydroxy analog, calcium salt, is 10-20% lower than that of DL-methionine on an equimolar
basis. Alternatively, analog producers claim that the bioefficacy of their products is equal to that that of
DL-methionine on an equimolar basis. Claimants are able to cite published scientific research in support
of their respective positions. A host of research experiments on relative bioefficacy have been conducted
using purified or crystalline diets, semipurified diets and practical diets such as those used in commercial
businesses, and a lay person reviewing the various scientific papers on bioefficacy is likely to wonder
whether there is a straightforward answer regarding the biological equivalence or difference of
The United States has been the major market in which all four products compete. With Rh?ne-Poulenc’s
construction of a U.S. analog production facility, making the company the first large-scale
producer/marketer of both major methionine products, and with MHA’s accounting for an ever-larger
share of the U.S. market, the debate over the relative bioefficacy of DL-methionine and methionine
hydroxy analog appears to have lost much of its fervor.
Primary end uses for these amino acids include food and feed additives, pharmaceuticals, raw materials
for the production of high-intensity sweeteners, and intermediates for pharmaceutical actives.
Seasonings/flavors/flavor enhancers. The manufacture of monosodium glutamate is the largest single
application for amino acids, accounting for some 1,162 thousand metric tons of glutamic acid annually.
While MSG is a relatively mature product in advanced economies, growth of consumption in China and
developing ASEAN nations will cause glutamic acid consumption to grow 3% annually through 2006.
Also, the production of savory flavors accounts for over 1,200 metric tons of cysteine/cystine each year.
Sweeteners. Since 1980, the growth in demand for L-phenylalanine and L-aspartic acid for the
manufacture of aspartame has been enormous. Since other uses for L-aspartic acid are small in volume
compared with use in the manufacture of aspartame, demand for L-aspartic acid will largely parallel
aspartame consumption, which is expected to grow by 2-3% per year globally between 2001 and 2006.
Largely because of aspartame’s success, consumption of L-phenylalanine and L-aspartic acid reached
some 12-13 thousand metric tons and 13-14 thousand metric tons, respectively, in 2001.
New high-intensity sweeteners include Neotame and Alitame, both made from L-aspartic acid. Alitame is
made from L-aspartic acid and L-alanine and is currently under FDA review. Neotame has been launched
in Australia in 2001 and received approval by the FDA in July 2002.
The National Academy of Sciences 1998 Nutrient Requirements of Swine combines the knowledge of
swine nutrition developed since publication of the 1988 edition with new information on thebioavailability of nutrients and a new approach to feeding which uses integrated mathematical models to
generate estimates of energy and amino acid requirements. A major change in this edition is that it
provides a computer program and software allowing users to generate tables of nutrient requirements for
swine of specific body weights, based on lean growth rate, gender and environmental conditions. It also
departs from earlier versions by including chapters that address minimizing nutrient excretion and the use
of nonnutritive feed additives.
Because of the many changes incorporated, it is not easy to compare the new NRC report with the earlier
edition with respect to amino acid requirements. There do appear to be some changes in requirements for
sows, with lactating sow requirements set a bit higher and gestating sow requirements a bit lower than
before. Overall, the new report promotes the concepts of more diet stages and more frequent dietary
changes. And it makes the ideal protein concept and its application readily understandable. However,
while the basic model appears user-friendly, it may not be so easy to customize—a quality which should
have been its real strength. Tacrolimus, Fk506
In general, industry response to the report seems to be quite favorable. Many see it as reinforcing current
industry practices regarding amino acid supplementation. There seems to be some concern, however, that
much of the empirical data underlying the report reflects old genetics with respect to feed intake and thus
may underestimate requirements. Overall, the impact of the 1998 Nutrient Requirements of Swine may be
to push up crystalline amino acid use as producers seek to insure a margin of safety (an extra 5% or so)
over what is recommended and as feed companies adjust the amino acid content of their prepared feeds in
light of the diversity in their client base. Tiagabine
The lean genotypic hog is now fairly well globalized. In the United States, about 80% of hogs are the
newer genotypes. There appears to be general agreement that these animals have higher amino acid
requirements than the standard types on both a percentage and grams-per-day basis, because they put on
more muscle per day. These genetic changes are compounded by the changes in production and feeding
systems that are ongoing in the industry, with SEW (segregated early weaning), wean-to-finish, all in-all
out, split-sex feeding and multiphase feeding becoming part of the industry vernacular. In general, the
changes in production systems are geared to improving herd health and reducing the immune response, so
that producers can get the best performance that the animal’s genetics permit. These approaches raise the
amino acid requirements marginally (up 5-10%) but this increase in requirements may be offset somewhat
by faster growth and better gains. And as the larger, more sophisticated producers expand, they “push”
these improved systems and practices down the size chain.