A vitamin is an essential organic compound and nutrient, or micronutrient, that organisms need in small amounts. An organic chemical compound (or a set of related compounds) is called a vitamin when the organism can not make the compound itself (either at all, or in sufficient quantities) and should be obtained by diet. Different organisms have different vitamin needs. For example, vitamin C is needed in food by humans and other primates, but other animals can synthesize it. Vitamin D is the necessary micronutrient when its synthesis, initiated by skin exposure to ultraviolet light, is insufficient due to lack of adequate skin exposure to sunlight.
By convention, the term vitamin excludes other essential nutrients, such as dietary minerals, essential fatty acids or essential amino acids. Thirteen vitamins are universally recognized today. Vitamins are classified by biological and chemical activity, and not their structure. Thus, each vitamin refers to a number of vitamine compounds that all exhibit the biological activity associated with a particular vitamin. Such a set of chemicals is grouped under the title "generic description" of vitamin alphabet, such as "vitamin A", which includes retinal compounds, retinol, and four known carotenoids. Vitamers by definition can be converted into active forms of vitamins in the body, and sometimes can be exchanged with each other, as well.
Vitamins have a variety of biochemical functions. Some, such as vitamin D, have functions such as hormones as mineral metabolism regulators, or cell and tissue growth regulators and differentiation (like some forms of vitamin A). Others function as antioxidants (eg, vitamin E and sometimes vitamin C). The largest amount of vitamins, vitamin B complex, serves as enzyme cofactors (coenzymes) or precursors to them; coenzymes help enzymes in their work as catalysts in metabolism. In this role, the vitamin may be closely bound to the enzyme as part of the prosthetic group: For example, biotin is part of the enzyme involved in the manufacture of fatty acids. They may also be bound less tightly with enzyme catalysts as coenzymes, detachable molecules that serve to carry chemical groups or electrons between molecules. For example, folic acid can carry methyl, methylene, methylene groups in the cell. Although these roles in assisting enzyme-substrate reactions are the best functions of vitamins, the function of other vitamins is equally important.
Before supplements are available, the only source of vitamin for humans comes from their diet. Then in the mid-1930s, the first complex yeast-extract commercial vitamins, and a semi-synthetic vitamin C supplement as tablets became available. This was followed in 1950 by the mass production of vitamin supplements, and their promotion. The addition of vitamins to staple foods to fortify them has prevented many vitamin deficiencies. The use of supplements is important for treating certain health problems, and during pregnancy but is considered to be of little value to a healthy person. The term vitamin comes from the word vitamine , created in 1912 by the biochemistry of Casimir Funk, which isolates the essential micronutrient complexes for life, all of which he considers as amines.. When this presumption is then determined incorrectly, "e" is omitted from the name.
Video Vitamin
Daftar vitamin
Each vitamin is usually used in various reactions, and therefore most have multiple functions.
Maps Vitamin
Source
For the most part, vitamins are derived from diet, but some are obtained by other means: for example, microorganisms in intestinal flora produce vitamin K and biotin; and one form of vitamin D is synthesized in skin cells when they are exposed to certain wavelengths of ultraviolet light present in the sun. Humans can produce several vitamins from the precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin was synthesized from tryptophan amino acids.
Classification by solubility
Vitamins are classified as soluble in water or soluble in fat. In humans there are 13 vitamins: 4 soluble in fat (A, D, E, and K) and 9 in water soluble (8 B vitamins and vitamin C).
Water-soluble vitamins are easily soluble in water and are, in general, readily excreted from the body, to the extent that urine output is a strong predictor of vitamin consumption. Since they are not ready to be stored, a more consistent intake is important.
Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fat). Because they are more likely to accumulate in the body, they are more likely to lead to hypervitaminosis than water-soluble vitamins. The regulation of fat-soluble vitamins is very important in cystic fibrosis.
Effects
In the growth of the fetus and childhood development
Vitamins are essential for the normal growth and development of multicellular organisms. By using a genetic blueprint passed on from his parents, the fetus begins to develop from the nutrients it absorbs. This requires certain vitamins and minerals to be present at certain times. These nutrients facilitate chemical reactions that produce, among others, skin, bones, and muscles. If there is a serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even small deficiencies can cause permanent damage.
On adult health care
Once growth and development are completed, vitamins remain essential nutrients for healthy maintenance of the cells, tissues, and organs that make up multicellular organisms; they also enable multicellular life forms to efficiently use the chemical energy provided by the food they eat, and to help process the proteins, carbohydrates, and fats required for cell respiration.
About cooking
USDA has conducted extensive studies on the percentage loss of various nutrients from different types of food and cooking methods.
Some vitamins can become more "bio-available" - which can be used by the body - when food is cooked.
The table below shows whether vitamins are susceptible to heat loss - such as the heat from boiling, steaming, frying, etc. The effect of cutting vegetables can be seen from exposure to air and light. Water-soluble vitamins such as B and C dissolve into water when the vegetables are boiled, and then disappear when water is removed.
Supplements
In those who are healthy, there is little evidence that supplements have benefits with respect to cancer or heart disease. Vitamin A and E supplements not only do not provide health benefits to healthy individuals in general, but they can increase mortality, although two major studies supporting this conclusion include smokers who are already known that beta-carotene supplements can be harmful. Other findings suggest that vitamin E toxicity is limited to certain forms when consumed in excess.
The EU and other European countries have regulations that set limits on the dosage of vitamins (and minerals) for their safe use as a dietary supplement. Most of the vitamins sold as dietary supplements should not exceed the maximum daily dose referred to as the tolerable upper intestine (UL) level. Vitamin products above these regulatory limits are not considered as supplements and should be listed as prescription or non-prescription (over the counter drugs) because of their potential side effects. The EU, the United States, Japan, and several other countries each set UL.
Food supplements often contain vitamins, but may also include other ingredients, such as minerals, herbs, and herbs. Scientific evidence supports the benefits of dietary supplements for people with certain health conditions. In some cases, vitamin supplements may have undesirable effects, especially if taken before surgery, with dietary supplements or other medications, or if the person taking them has certain health conditions. They can also contain vitamin levels that are many times higher, and in different forms, than can be swallowed through food.
Deficient intake
Humans should take vitamins periodically but with different schedules, to avoid deficiencies. Body stores for different vitamins vary; vitamins A, D, and B 12 are stored in significant amounts, especially in the liver, and the adult diet may be deficient in vitamin A and D for months and B 12 in some cases over the years, before developing a deficiency condition. However, vitamin B 3 (niacin and niacinamide) is not stored in significant amounts, so the store can only last for several weeks. For vitamin C, the first symptom of scurvy in an experimental study of complete vitamin C deficiency in humans has varied widely, from one month to more than six months, depending on previous dietary history that determines body storage.
Vitamin deficiencies are classified as primary or secondary. Primary deficiency occurs when an organism does not get enough vitamins in its diet. Secondary deficiencies may be caused by an underlying disorder that prevents or limits the absorption or use of vitamins, due to "lifestyle factors", such as smoking, excessive alcohol consumption, or the use of drugs that interfere with absorption or use. vitamin. People who eat varied foods are unlikely to experience severe primary vitamin deficiency. In contrast, strict diets have the potential to cause prolonged vitamin deficits, which can lead to painful and potentially lethal diseases.
Well-known human vitamin deficiency involves thiamine (beriberi), niacin (pellagra), vitamin C (scabies), and vitamin D (rickets). In many developed countries such deficiencies are rare; this is due to (1) adequate food supplies and (2) the addition of vitamins and minerals to the common food (fortification). In addition to this classic vitamin deficiency disease, some evidence also shows a link between vitamin deficiency and a number of different disorders.
Excess intake
Some vitamins have documented side effects that tend to be more severe with larger doses. The possibility of consuming too much vitamin from food is far away, but overdose (vitamin toxicity) from vitamin supplementation does occur. Acute symptoms may include nausea, vomiting and diarrhea. In the United States, the Institute of Medicine of National Academies has established a Tolerable (ULs) intake level for vitamins that have documented side effects on high intake. In the European Union, the European Food Safety Authority has also established UL. The ULS of the two organizations does not always match.
By 2014, overdose exposure to all vitamin formulations and multi-vitamin/mineral formulations was reported by 68,058 people to the American Association of Poison Control Centers with 73% of these exposures in children under the age of five.
Society and culture
Promotions
Once found, vitamins are actively promoted in articles and ads on McCall's , Good Housekeeping , and other media outlets. Marketers enthusiastically promote cod liver oil, a source of Vitamin D, as "sunlight bottles", and bananas as "natural vitality foods". They promote food like yeast cake, a source of B vitamins, based on scientifically determined nutritional value, not taste or appearance. World War II researchers focused on the need to ensure adequate nutrition, especially in processed foods. Robert W. Yoder is credited with first using the term vitamania , in 1942, to illustrate the appeal of relying on nutritional supplements rather than getting vitamins from a diverse dietary diet. The continued preoccupation with a healthy lifestyle has led to the consumption of obsessive additive beneficial effects being questioned.
Commercial production
Until the mid-1930s, when the first commercially available vitamin B complex and semi-synthetic supplements were sold, vitamins were obtained only through food. Vitamins have been produced as a cheap supplement since the 1950s.
Government regulation
Most countries place dietary supplements in a special category under the general umbrella of food, not drugs. As a result, producers, and not governments, have a responsibility to ensure that their food supplement products are safe before they are marketed. Supplementary regulations vary by country. In the United States, dietary supplements were defined under the Supplementary Health and Education Act of 1994. There is no FDA approval process for dietary supplements, and there is no requirement that manufacturers prove the safety or efficacy of supplements introduced before 1994. Food and Drug Administration rely on the Adverse Event Reporting System to monitor the side effects that occur with supplements. In 2007, the US Federal Regulatory Code (CFR) Title 21, section III applies, regulates Good Manufacturing Practices (GMP) in manufacturing, packaging, labeling, or containment operations for dietary supplements. Although product registration is not required, this rule requires production and quality control standards (including testing for identity, purity and forgeries) for dietary supplements. In the European Union, the Food Supplements Directive requires that only safely proven supplements can be sold without a prescription. For most vitamins, pharmacopoeia standards have been established. In the United States, the United States Pharmacopeia (USP) sets the standard for the most commonly used vitamins and preparations. Likewise, the monograph of the European Pharmacopoeia (Ph.Eur.) Regulates the identity and purity aspects of vitamins in the European market.
Naming
The reason why the vitamin set jumps directly from E to K is that vitamins related to the F-J letters are reclassified all the time, disposed of as false hints, or renamed because of their association with vitamin B, which is a complex of vitamins.
German-speaking scientists who isolate and explain vitamin K (in addition to naming it) do so because the vitamin is closely involved in blood coagulation after injury (from the German word Coagulation ). At that time, most (but not all) of the letters from F to J were designated, so the use of the letter K was considered quite reasonable. The table reclassified vitamin nomenclature lists chemicals previously classified as vitamins, as well as the names of previous vitamins that later became part of the B-complex.
There are other missing B vitamins that are reclassified or determined not to be vitamins. For example, B 9 is folic acid and five folates are in the range of B 11 via B 16 , other vitamin forms have been found, not required as nutrition by the entire population (such as B 10 , PABA for internal use), are not biologically active, toxic, or with effects that can not be classified in humans, or are not generally recognized as vitamins by science , such as the highest number, which by some naturopath practitioners is called B 21 and B 22 . There are also nine vitamin B complex letters (eg B m ). There is another vitamin D which is now known as another substance, which is several sources of the same type up to D 7 . Laetrile controversial cancer treatment is at one point a letter as vitamin B 17 . There seems to be no consensus on vitamins Q, R, T, V, W, X, Y or Z, nor is there any substance that is officially designated as Vitamin N or I, though the latter may be another form of one of the other. vitamins or nutrients that are known and named other types.
Anti-vitamin
Anti-vitamins are chemical compounds that inhibit the absorption or action of vitamins. For example, avidin is a protein in raw egg white that inhibits the absorption of biotin; it is disabled with cooking. Pyrithiamine, a synthetic compound, has a molecular structure similar to thiamine, vitamin B 1 , and inhibits an enzyme that uses thiamine.
History
The value of eating certain foods to maintain health is recognized long before the vitamin is identified. The ancient Egyptians knew that feeding the heart to a person could help with night blindness, a disease that is now known to be caused by vitamin A deficiency. The advancement of oceanic voyages during the Renaissance period resulted in prolonged periods without access to fresh fruits and vegetables, and made the disease of vitamin deficiency which is common among the crew.
In 1747, Scottish surgeon James Lind discovered that citrus fruits help prevent scurvy, a highly lethal disease in which collagen is not well formed, leading to poor wound healing, gum hemorrhage, severe pain, and death. In 1753, Lind published her book Treatise on the Scurvy , which recommended using lemons and limes to avoid scabies, which was adopted by the Royal Navy. This led to the nickname of limey for English sailors. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expedition in the 19th century, where it is widely believed that scurvy can be prevented by practicing good hygiene, regular exercise, and maintaining the morale of crew while on board, than with a fresh food diet. As a result, the Arctic expedition continues to be plagued by scurvy and other deficiencies. At the beginning of the 20th century, when Robert Falcon Scott undertook two expeditions to Antarctica, the prevailing medical theory at the time was that scabies was caused by "contaminated" canned foods.
During the 18th and early 19th centuries, the use of deprivation studies enabled scientists to isolate and identify a number of vitamins. Lipid from fish oil is used to cure rickets in mice, and fat-soluble nutrients are called "antirachitic A". Thus, the first "vitamin" bioactivity ever isolated, which heals rickets, was originally called "vitamin A"; However, the bioactivity of these compounds is now called vitamin D. In 1881, Russian medical doctor Nikolai I. Lunin studied the effects of scurvy at the University of Tartu. He fed artificial mixed rats from all the separate milk constituents at the time, namely protein, fat, carbohydrates, and salt. Mice that only receive individual constituents die, while mice fed themselves develop normally. He concludes that "natural foods like milk should contain, in addition to this known main ingredient, a small amount of unknown substances that are essential to life." However, his conclusions were rejected by his counselor, Gustav von Bunge, even after another student reproduced the results. Similar results by Cornelius Pekelharing appeared in the Dutch medical journal in 1905, but were not widely reported.
In East Asia, where white rice is polished is a common middle-class staple food, berries resulting from vitamin B deficiency 1 are endemic. In 1884, Takaki Kanehiro, a medical doctor of the Imperial Japanese Navy trained in the UK, observed that beriberi was endemic among low-level crews who often ate rice, but not among officers who ate Western-style diets. With the support of the Japanese navy, he experimented with the crew of two warships; one crew was fed only white rice, while others were fed meat, fish, barley, rice, and beans. The group that eats only white rice documenting 161 crew members with beriberi and 25 deaths, while the last group has only 14 cases of beriberi and no deaths. This convinced Takaki and the Japanese Navy that diet was the cause of beriberi, but they mistakenly believed that a sufficient amount of protein prevented it. The diseases could result from some dietary deficiencies that were later investigated by Christiaan Eijkman, who in 1897 found that feeding unwashed rice instead of various polishes for chickens, helped prevent beriberi on chickens. The following year, Frederick Hopkins postulated that some foods contain "accessory factors" - other than proteins, carbohydrates, fats, etc. - necessary for the functioning of the human body. Hopkins and Eijkman were awarded the Nobel Prize for Physiology or Medicine in 1929 for their discovery.
In 1910, the first vitamin complex was isolated by Japanese scientist Umetaro Suzuki, who succeeded in extracting a water-soluble micronutrient complex from rice bran and named it aberat acid (later Orizanin ). He published this discovery in Japanese scientific journals. When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his invention failed to gain publicity. In 1912, the Polish-born biochemist Casimir Funk, who worked in London, alienated the same complex of micronutrients and proposed to be named "vitamine". It came to be known as vitamin B 3 (niacin), although it described it as "anti-beri-factor" (which would now be called thiamine or vitamin B 1 ). Funk hypothesized that other diseases, such as rickets, pellagra, celiac disease, and scabies can also be cured by vitamins. Max Nierenstein a friend and Biochemistry reader at Bristol University reportedly suggested the name "vitamine" (from "vital amine"). The name soon became synonymous with Hopkins 'accessory factor', and, at the time it was shown that not all vitamins are amines, the word is already ubiquitous. In 1920, Jack Cecil Drummond proposed that the last "e" be dropped not to emphasize the "amine" reference, after the researchers began to suspect that not all "vitamines" (specifically, vitamin A) had amine components.
In 1930, Paul Karrer explains the correct structure for beta-carotene, the main precursor of vitamin A, and identifies other carotenoids. Karrer and Norman Haworth confirmed the discovery of Albert Szent-GyÃÆ'¶rgyi about ascorbic acid and made a significant contribution to flavin chemistry, which led to the identification of lactoflavin. For their investigation of carotenoids, flavins and vitamins A and B 2 , they both received the Nobel Prize in Chemistry in 1937.
In 1931, Albert Szent-GyÃÆ'¶rgyi and fellow researcher Joseph Svirbely suspect that "hexuronic acid" is actually vitamin C, and gives a sample to Charles Glen King, which proves his anti-scorbutic activity in long-established scorbutic guinea pigs. assay. In 1937, Szent-GyÃÆ'¶rgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for the discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A can participate directly in physiological processes.
Etymology
The term vitamin comes from "vitamine", a compound word coined in 1912 by Polish biochemist Casimir Funk while working at the Lister Institute of Preventive Medicine. Its name is from vital and amine , which means amine life, because in 1912 it was suggested that organic micronutrient food factors that prevent beriberi and possibly other similar deficiency diseases. possibly chemical amines. This is true thiamine, but after it was discovered that another such micronutrient was not suitable, the word was abbreviated to vitamin in English.
See also
- Provitamin
References
External links
- The USDA RDA graph in PDF format
- Canadian Health Diet References Intake Reference Chart for Vitamins
- NIH Office of Dietary Supplements: Fact Sheet
Source of the article : Wikipedia
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