More interesting methionine and deficiency info
METHIONINE is an essential amino acid that cannot be synthesized in
the body, but must be obtained from food sources or from dietary
supplements. Methionine is a precursor for the other sulfur amino
acids, cystine, taurine, and glutathione. It has the ability to be a
methyl donor to other molecules, which is essential in formulating RNA
and DNA. Methionine is necessary for the absorption, transportation,
and bioavailability of selenium. In order to be properly utilized,
methionine requires the help of its cofactors -- Vitamins B6, B12, Bc,
choline, folic acid, and magnesium.
Methionine is an antioxidant and, because it has a methyl group, it
can combine with active free radicals. However, its derivative,
homocysteine, is a powerful oxidant. Adequate levels of B6 are
required to allow this harmful compound to be reconverted into an
antioxidant substance called cystathione. A high meat intake with an
inadequate supply of B6 would produce this type of situation, as would
high methionine supplementation without additional B6. The result is
cardiovascular disease. Methionine is important in the formation of
blood proteins, globulins, and albumins. It also assists in the
breakdown of fats, preventing their buildup in the liver and arteries,
which can obstruct blood flow to the brain, heart, and kidneys.
Methionine is important in the treatment of rheumatic fever and
pregnancy-induced toxemia. With the help of choline and folic acid,
methionine is a chelator for heavy metals and helps remove them from
the body. Methionine is also used as an antidote in paracetamol
poisoning -- a pain killer available by prescription and in
over-the-counter analgesics -- and to lower urinary pH, making it more
acidic.
The body uses methionine to derive a brain food called choline.
Therefore, choline or lecithin (which is high in choline) should be
added to the diet so that the supply of methionine is not depleted.
Beans are low in methionine but rich in lysine; and, since most grains
are low in lysine and rich in methionine, combining beans and grains
will give a full complement of amino acids.
Methionine deficiency causes the liver to metabolize only histidine to
form, resulting in an incomplete form of folic acid. From this,
researchers conclude that methionine is a key factor in regulating the
availability of folate. When methionine levels are low, folate becomes
trapped in the liver as 5-methyl-tetrahydrofolate, causing a temporary
folic acid deficiency since this form cannot be used. This is also
seen in Vitamin B12 deficiencies and may be an important factor in all
allergy and some anemia patients.
Since 1970, methionine deficiencies have been attributed to such
ailments as toxemia, childhood rheumatic fever, muscle paralysis, hair
loss, depression, schizophrenia, Parkinson's, liver deterioration, and
impaired growth.
Food sources include beans, eggs, fish, garlic, lentils, meat, onions,
soybeans, seeds, yogurt.
Other names for Methionine include: MET, amino acid M, and
2-amino-4(methylthio)-buanoic acid.
--- In FairfieldLife@yahoogroups.com, akasha_108 <[EMAIL PROTECTED]> wrote:
>
> Since Methionine is the one essential amino acid often at lowest
> levels in veg, particularly soy/tofu based diet, symtoms of Methionine
> deficiency are good to know.
>
> Methionine deficiency
> Methionine deficiency is caused by an abundance of the ß-chain of
> ß-conglycinin, a seed storage protein that lacks methionine.
> Methionine deficiency is associated with a deficiency of
> S-adenosylmethionine which acts as an endogenous anti-depressant. Most
> people consume plenty of methionine through a typical diet. Lower
> intakes during pregnancy have been associated with neural tube defects
> in newborns. Methionine deficiency (primarily in salmonids) leads to
> reduced growth rate with the development of bilateral cataracts.
> (Zinc, and cystine deficiencies can also cause cataracts) It is felt
> that deficiencies of vitamin A and riboflavin also play a role in this
> lesion. Methionine deficiency causes the liver to metabolize only
> histidine to form, resulting in an incomplete form of folic acid.
> Methionine deficiency can cause apathy, loss of pigmentation in hair,
> edema, lethargy, liver damage, muscle loss, fat loss, skin lesions,
> weakness, and slowed growth in children.
>
>
> -------
>
> More on Methionine
>
> Methionine, organic compound, one of the 20 amino acids commonly found
> in animal proteins. Methionine is one of the several essential amino
> acids needed in the diet; the human body cannot synthesize it from
> simpler metabolites. Methionine supplies sulfur and other compounds
> required by the body for normal metabolism and growth. It is an
> important source of dietary sulfur. Methionine also belongs to a group
> of compounds called lipotropics; others in this group include choline,
> inositol, and betaine. Methionine is one of only two amino acids
> encoded by just one codon (AUG) in the standard genetic code
> (tryptophan, encoded by UGG, is the other). L-methionine is a
> sulfur-containing amino acid that is minimally soluble in water. Its
> sulfur is non reactive.
>
> Methionine functions, uses, and health benefits
> Methionine reacts with adenosine triphosphate to form S-adenosyl
> methionine. S-adenosyl methionine is the principal methyl donor in the
> body and contributes to the synthesis of many important substances,
> including epinephrine and choline. SAMe is
> involved in the synthesis of creatine, epinephrine, melatonin and the
> polyamines spermine and spermidine, among several other substances.
> Since methionine is the only essential amino acid not present in
> significant amounts of soybeans, it is produced commercially as an
> additive for soybean meal. Methionine is incorporated into the
> N-terminal position of all proteins in eukaryotes and archaea.
> Methionine plays a role in cysteine, carnitine and taurine synthesis
> by the transsulfuration pathway, lecithin production, the synthesis of
> phosphatidylcholine and other phospholipids.
>
> Methionine in lipotropic combinations has been proposed for treating
> endometriosis, a condition in which patches of endometrial tissue from
> the uterine lining grow outside the uterus. Methionine is an
> especially important nutrient beneficial for those suffering from
> estrogen dominance, where the amount of estrogen in the body is
> excessively high when compared to its opposing hormone called
> progesterone. The nutrient is believed to help by expediting the
> removal of excess estrogen from the liver.
>
> Methionine is both an antioxidant and lipotrope, meaning it helps
> remove fat from the liver. Methionine contributes to the
> hydrophobicity of a protein. Methionine controls the level of
> beneficial sulfur-containing compounds in the body. These
> sulfur-containing compounds are in turn vital for defending against
> toxic compounds like heavy metals in the liver. Methionine helps
> reduce histamine levels, which are amino acids that control dilation
> of blood vessels and influence brain function.
>
> Dietary sources of methionine
>
> Meat, fish, and dairy products are all excellent sources of
> methionine. L-methionine is also found in fruits and vegetables, but
> not as abundantly. Small amounts of free L-methionine occur in
> vegetables, vegetable juices and fermented foods. Vegetarians can
> obtain methionine from whole grains.
>
> Methionine dosage, intake
>
> Amino acid requirements vary according to body weight. L-methionine
> supplements should only be taken with a physician's recommendation.
> According to the Food and Agriculture Organization of the United
> Nations (FAO) and World Health Organization (WHO), recommended daily
> L-methionine intake is 13 mg per kg or about one gram daily for
> adults. During methionine supplementation, intake of taurine,
> cysteine, and other sulfur containing amino acids, as well as B6 and
> folic acid should also be included.
>
>
> Toxicity, side effects, interactions, and contraindications
> Excessive methionine intake, together with inadequate intake of folic
> acid, vitamin B6, and vitamin B12, can increase the conversion of
> methionine to homocysteine. Homocysteine is a potentially harmful
> blood fat that has been linked to atherosclerosis (hardening of the
> arteries). L-methionine supplementation should be avoided by those
> with neoplastic disease and elevated homocysteine levels and used with
> caution in those with coronary heart disease. L-methionine supplements
> should be avoided by pregnant women and nursing mothers unless they
> are prescribed by a physician. There are no known drug or nutrient
> interactions associated with methionine.
>
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