Popular Posts

Saturday, May 28, 2011

vitamin...BOTOX..wakakakakkaka;))

1. Vitamin A

*Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is absolutely necessary for both low-light (scotopic vision) and color vision. Vitamin A also functions in a very different role, as an irreversibly oxidized form of retinol known as retinoic acid, which is an important hormone-like growth factor for epithelial and other cells.

In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to the retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. The associated acid (retinoic acid), a metabolite that can be irreversibly synthesized from vitamin A, has only partial vitamin A activity, and does not function in the retina for the visual cycle.

All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group. Both structural features are essential for vitamin activity.[1] The orange pigment of carrots – beta-carotene – can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans.

Vitamin A can be found in two principal forms in foods:
Retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble substance. Since the pure alcohol form is unstable, the vitamin is found in tissues in a form of retinyl ester. It is also commercially produced and administered as esters such as retinyl acetate or palmitate.
The carotenes alpha-carotene, beta-carotene, gamma-carotene; and the xanthophyll beta-cryptoxanthin (all of which contain beta-ionone rings), but no other carotenoids, function as vitamin A in herbivores and omnivore animals, which possess the enzyme required to convert these compounds to retinal. In general, carnivores are poor converters of ionine-containing carotenoids, and pure carnivores such as cats and ferrets lack beta-carotene 15,15'-monooxygenase and cannot convert any carotenoids to retinal (resulting in none of the carotenoids being forms of vitamin A for these species)
2. Vitamin E

*Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols.[1] There are many different forms of vitamin E, of which ?-tocopherol is the most abundant in the North American diet.[2] ?-Tocopherol can be found in corn oil, soybean oil, margarine and dressings.[3][4] a-Tocopherol, the most biologically active form of vitamin E, is the second most abundant form of vitamin E in the North American diet. This variant of vitamin E can be found most abundantly in wheat germ oil, sunflower, and safflower oils.[4][5] It is a fat-soluble antioxidant that stops the production of reactive oxygen species formed when fat undergoes oxidation.

3. Vitamin K

*Vitamin K is a group of fat soluble vitamins that are needed for the posttranslational modification of certain proteins, mostly required for blood coagulation but also involved in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives.

Vitamin K1 is also known as phylloquinone or phytomenadione (also called phytonadione). Vitamin K2 (menaquinone, menatetrenone) is normally produced by bacteria in the large intestine,[1] and the old theory says that dietary deficiency is extremely rare unless the intestines are heavily damaged, are unable to absorb the molecule, or are subject to decreased production by normal flora, as seen in broad spectrum antibiotic use.[2] However, recent research results shows that this might not be the case, the bowel seems to be inefficient in the absorption of vitamins K. [3] ; [4]. These results are reinforced by human cohorts studies, where a majority of the subjects showed inadequate vitamins K amounts in the body. This was revealed by the presence of large amounts of incomplete gamma-carboxylated proteins in the blood, an indirect test for vitamins K deficiency. [5] ; [6] ; [7]

There are three synthetic forms of vitamin K, vitamins K3, K4, and K5, which are used in many areas including the pet food industry (vitamin K3) and to inhibit fungal growth (vitamin K5).[8]

4. Cobalamine

*Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the human body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production. As the largest and most structurally complicated vitamin, it can be produced industrially only through bacterial fermentation-synthesis.

Vitamin B12 consists of a class of chemically-related compounds (vitamers), all of which have vitamin activity. It contains the biochemically rare element cobalt. Biosynthesis of the basic structure of the vitamin in nature is only accomplished by simple organisms such as some bacteria and algae, but conversion between different forms of the vitamin can be accomplished in the human body. A common synthetic form of the vitamin, cyanocobalamin, does not occur in nature, but is used in many pharmaceuticals and supplements, and as a food additive, because of its stability and lower cost. In the body it is converted to the physiological forms, methylcobalamin and adenosylcobalamin, leaving behind the cyanide, albeit in minimal concentration. More recently, hydroxocobalamin (a form produced by bacteria), methylcobalamin, and adenosylcobalamin can also be found in more expensive pharmacological products and food supplements. The extra utility of these is currently debated.

Vitamin B12 was discovered from its relationship to the disease pernicious anemia, which is an autoimmune disease that destroys parietal cells in the stomach that secrete intrinsic factor. Intrinsic factor is crucial for the normal absorption of B12, so a lack of intrinsic factor, as seen in pernicious anemia, causes a vitamin B12 deficiency. Many other subtler kinds of vitamin B12 deficiency and their biochemical effects have since been elucidated.


5. Zinc

*Zinc (pronounced /'z??k/ zingk; from German: Zink), also known as spelter, is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2. Zinc is the 24th most abundant element in the Earth's crust and has five stable isotopes. The most exploited zinc ore is sphalerite, a zinc sulfide. The largest exploitable deposits are found in Australia, Asia, and the United States. Zinc production includes froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).

Brass, which is an alloy of copper and zinc, has been used since at least the 10th century BC. Impure zinc metal was not produced in large scale until the 13th century in India, while the metal was unknown to Europe until the end of the 16th century. Alchemists burned zinc in air to form what they called "philosopher's wool" or "white snow".

The element was probably named by the alchemist Paracelsus after the German word Zinke. German chemist Andreas Sigismund Marggraf is normally given credit for discovering pure metallic zinc in 1746. Work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of steel (hot-dip galvanizing) is the major application for zinc. Other applications are in batteries and alloys, such as brass. A variety of zinc compounds are commonly used, such as zinc carbonate and zinc gluconate (as dietary supplements), zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in luminescent paints), and zinc methyl or zinc diethyl in the organic laboratory.

Zinc is an essential mineral of "exceptional biologic and public health importance".[1] Zinc deficiency affects about two billion people in the developing world and is associated with many diseases.[2] In children it causes growth retardation, delayed sexual maturation, infection susceptibility, and diarrhea, contributing to the death of about 800,000 children worldwide per year.[1] Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc can cause ataxia, lethargy and copper deficiency.


6. Calcium

*Calcium ( /'kælsi?m/ KAL-see-?m) is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[2]

Calcium is essential for living organisms, particularly in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bones and shells, calcium is the most abundant metal by mass in many animals.


7. Thiamine

*Thiamine or thiamin or vitamin B1 (pronounced /'?a?.?m?n/ THY-?-min), and named as the "thio-vitamine" ("sulfur-containing vitamin") is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are involved in many cellular processes. The best-characterized form is thiamine pyrophosphate (TPP), a coenzyme in the catabolism of sugars and amino acids. In yeast, TPP is also required in the first step of alcoholic fermentation.

All living organisms use thiamine in their biochemistry, but it is synthesized in bacteria, fungi, and plants. Animals must obtain it from their diet, and, thus, for them it is a vitamin. Insufficient intake in birds produces a characteristic polyneuritis, and in mammals results in a disease called beriberi affecting the peripheral nervous system (polyneuritis) and/or the cardiovascular system, with fatal outcome if not cured by thiamine administration.[1] In less severe deficiency, nonspecific signs include malaise, weight loss, irritability and confusion.[2]

There is still much work devoted to elucidating the exact mechanisms by which thiamine deficiency leads to the specific symptoms observed (see below). New thiamine phosphate derivatives have recently been discovered,[3] emphasizing the complexity of thiamine metabolism and the need for more research in the field.

Thiamine derivatives with improved pharmacokinetics have been discovered and are to be considered more effective in alleviating the symptoms of thiamine deficiency and other thiamine-related conditions such as impaired glucose metabolism in diabetes. These compounds include allithiamine, prosultiamine, fursultiamine, benfotiamine, and sulbutiamine, among others


8. Iodine

*odine is an essential trace element; the thyroid hormones thyroxine and triiodotyronine contain iodine. In areas where there is little iodine in the diet—typically remote inland areas where no marine foods are eaten—iodine deficiency gives rise to goiter (so-called endemic goiter), as well as cretinism, which results in developmental delays and other health problems. While noting recent progress, The Lancet noted, "According to WHO, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age. ... Thus iodine deficiency, as the single greatest preventable cause of mental retardation, is an important public-health problem."[1]

In some such areas, this is now combatted by the addition of small amounts of iodine to table salt in form of sodium iodide, potassium iodide, and/or potassium iodate—this product is known as iodized salt. Iodine compounds have also been added to other foodstuffs, such as flour, water and milk in areas of deficiency.[2] Seafood is also a well known source of iodine.[3] Thus, iodine deficiency is more common in mountainous regions of the world where food is grown in soil poor in iodine.


9. Riboflavin

Riboflavin, also known as vitamin B2 or additive E101,[1] is an easily absorbed micronutrient with a key role in maintaining health in humans and other animals[which?]. It is the central component of the cofactors FAD and FMN, and is therefore required by all flavoproteins. As such, vitamin B2 is required for a wide variety of cellular processes. It plays a key role in energy metabolism, and for the metabolism of fats, ketone bodies, carbohydrates, and proteins.

Milk, cheese, leafy green vegetables, liver, kidneys, legumes, tomatoes, yeast, mushrooms, and almonds[2] are good sources of vitamin B2, but exposure to light destroys riboflavin.

The name "riboflavin" comes from "ribose" (the sugar which forms part of its structure, which in turn is a transposition of arabinose[3]) and "flavin", the ring-moiety which imparts the yellow color to the oxidized molecule (from Latin flavus, "yellow"). The reduced form, which occurs in metabolism, is colorless.

Riboflavin is best known visually as the vitamin which imparts the orange color to solid B-vitamin preparations, the yellow color to vitamin supplement solutions, and the unusual fluorescent yellow color to the urine of persons who supplement with high-dose B-complex preparations (no other vitamin imparts any color to urine)


10. Pyridoxine

*Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'

It is based on a pyridine ring, with hydroxyl, methyl, and hydroxymethyl substituents. It is converted to the biologically active form pyridoxal 5-phosphate.
Function in the body

Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. It is linked to cardiovascular health by decreasing the formation of homocysteine. Pyridoxine may help balance hormonal changes in women and aid the immune system.[citation needed] Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth.[2]

It is required for the production of the monoamine neurotransmitters serotonin, dopamine, norepinephrine and epinephrine, as it is the precursor to pyridoxal phosphate: cofactor for the enzyme aromatic amino acid decarboxylase. This enzyme is responsible for converting the precursors 5-hydroxytryptophan (5-HTP) into serotonin and levodopa (L-DOPA) into dopamine, noradrenaline and adrenaline. As such it has been implicated in the treatment of depression and anxiety.[citation needed]

A very good source of pyridoxine is dragon fruit from South East Asia.

No comments:

Post a Comment