Pre Postoje 3 srodna oblika: A1, A2 i A3. Dnevne potrebe za ovim vitaminom: 0,8 do 1,5 mg. Kristalno jedinjenje rastvorljivo u vodi i alkoholima. Osetljiv je na toplotu, bazne rastvore i oksidaciona sredstva. Dnevne potrebe za ovim vitaminom: ,2 mg. Dnevne potrebe za ovim vitaminom: mg.
Dnevne potrebe za ovim vitaminom: 1, mg. Dnevne potrebe za ovim vitaminom: oko 3 mkg. Distillations Magazine 1 3 : 41— Vitamania: Our obsessive quest for nutritional perfection. Penguin Press. Nutrition Journal 7 : 2. Nutrition Reviews. Clinical Toxicology 55 10 : — Cooked Foods. Kereaktifan oksigen ini sangat berbahaya bagi tubuh karena dapat mengoksidasi dan merusak DNA , protein , karbohidrat , asam lemak , dan membran sel di dalam tubuh. Sumber radikal bebas lainnya adalah asap rokok , polusi lingkungan, dan sinar ultraviolet.
Tubuh memiliki beberapa mekanisme pertahanan terhadap senyawa radikal bebas ini untuk menetralkan efek negatifnya. Kebanyakan diantaranya adalah senyawa antioksidan alami, seperti enzim superoksida dismutase , katalase , dan glutation peroksidase.
Antioksidan sendiri berarti senyawa yang dapat mencegah terjadinya peristiwa oksidasi atau reaksi kimia lain yang melibatkan molekul oksigen O 2. Contoh vitamin yang banyak berperan sebagai senyawa antioksidan di dalam tubuh adalah vitamin C dan vitamin E. Vitamin E dapat membantu melindungi tubuh dari oksidasi senyawa radikal bebas. Di samping vitamin E, terdapat satu jenis vitamin lagi yang juga memiliki aktivitas antioksidan yang tinggi, yaitu vitamin C.
Vitamin ini berinteraksi dengan senyawa radikal bebas di bagian cairan sel. Selain itu, vitamin C juga dapat memulihkan kondisi tubuh akibat adanya reaksi oksidasi dari berbagai senyawa berbahaya.
Bila kadar radikal bebas di dalam tubuh menjadi sangat berlebih dan tidak lagi dapat diantisipasi oleh senyawa antioksidan maka akan timbul berbagai penyakit kronis, seperti kanker , arterosklerosis , penyakit jantung , katarak , alzhemeir , dan reumatik. Selain itu, suplemen makanan juga dapat turut membantu mengatasi masalah tersebut.
Penuaan tubuh merupakan hasil akumulasi dari berbagai kerusakan sel dan jaringan yang tidak dapat diperbaiki. Pada keadaan normal, kerusakan pada sel dan jaringan tubuh dapat diperbaiki melalui proses replikasi sel tubuh yang juga dikenal dengan istilah mitosis.
Hal inilah yang berpotensi menyebabkan penuaan pada tubuh. Mitokondria merupakan salah satu organel sel yang paling rentan mengalami kerusakan oleh senyawa oksigen reaktif radikal bebas. Hal ini terkait dengan banyaknya reaksi pelepasan oksigen bebas di dalam organel ini yang merupakan pusat metabolisme energi tubuh.
Selain itu, kerusakan DNA akibat reaksi oksidasi oleh radikal bebas juga turut berperan besar dalam peristiwa ini.
Vitamin merupakan satu dari berbagai jenis senyawa yang dapat menghambat reaksi perusakan tubuh best bodybuilding supplements oleh senyawa radikal bebas terkait dengan aktivitas antioksidannya.
Asupan vitamin antioksidan yang cukup akan membantu tubuh mengurangi efek penuaan oleh radikal bebas, terutama oleh oksigen bebas yang reaktif. Jadi, secara tidak langsung, asupan vitamin yang cukup dan seimbang dapat menciptakan kondisi tubuh yang sehat dan berumur panjang.
Dari Wikipedia bahasa Indonesia, ensiklopedia bebas. Daftar isi. Diakses tanggal Mikroskop Avitaminosis". The Past, Present and Future of Vitamins. Vitamin: How Much is Too Much??. Harper Collins. Niacin lowers serum phosphate and increases HDL cholesterol in dialysis patients.
Pengertian dan Definisi Vitamin". Linus Pauling Institute. Diakses tanggal 19 Apr Supplements Store. Gjendet ne arra, oriz, banane dhe sardina. B9-Eshte i rendesishem per zhvillimin e qelizave te reja, dhe sidomos tek krijimi i rruazave te kuqe te gjakut.
Per shkak te ketij roli kjo vitamine eshte e nevojshme ne ushqimin e femijeve dhe shtatzenave. Gjenden ne melci, perime te gjelbra dhe ne drithera integrale. BNdikon vecanerisht ne disponim te mire, ule nervozen, permireson perqendrimin dhe kujtesen.
Parandalon anemine, dhe ndihmon ne rritjen e femijeve dhe shton oreksin. Nutricionistet kohe te gjate jane te bindur se vitamine B12 permbajne vetem ushqimet me prejardhje shtazore melcia, vezet, peshku , si edhe gjendet ne majen e birres, megjithate studimet me te reja treguan se edhe disa ushqime me prejardhje bimore jane te pasura me kete vitamine si: panxhari, disa lloje te dritherave, susami, lajthia, soja etj.
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Disa nga vitaminat te cilat forcojne imunitetin Vitamina A Vitamina A apo beta-karoteni gjendet ne ushqime me prejardhje bimore dhe shtazore. Likewise, monographs of the European Pharmacopoeia Ph.
At the time, most but not all of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable.
The missing B vitamins were reclassified or determined not to be vitamins. For example, B 9 is folic acid and five of the folates are in the range B 11 through B Others, such as PABA formerly B 10 , are biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science,  such as the highest-numbered, which some naturopath practitioners call B 21 and B There are also nine lettered B complex vitamins e.
There are other D vitamins now recognised as other substances, which some sources of the same type number up to D 7. The controversial cancer treatment laetrile was at one point lettered as vitamin B There appears to be no consensus on any vitamins Q, R, T, V, W, X, Y or Z, nor are there substances officially designated as vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.
The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding liver to a person may help with night blindness , an illness now known to be caused by a vitamin A deficiency.
In , the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy , a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums , severe pain, and death. This led to the nickname limey for British sailors. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene , regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food.
In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic , the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food. During the late 18th and early 19th centuries, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Lipid from fish oil was used to cure rickets in rats , and the fat-soluble nutrient was called "antirachitic A". Thus, the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A"; however, the bioactivity of this compound is now called vitamin D.
He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins , fats , carbohydrates , and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally.
He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life. In East Asia , where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B 1 was endemic. In , Takaki Kanehiro , a British-trained medical doctor of the Imperial Japanese Navy , observed that beriberi was endemic among low-ranking crew who often ate nothing but rice, but not among officers who consumed a Western-style diet.
With the support of the Japanese navy, he experimented using crews of two battleships ; one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented crew members with beriberi and 25 deaths, while the latter group had 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 sufficient amounts of protein prevented it.
In , the first vitamin complex was isolated by Japanese scientist Umetaro Suzuki , who succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid later Orizanin. He published this discovery in a Japanese scientific journal. In Polish-born biochemist Casimir Funk , working in London, isolated the same complex of micronutrients and proposed the complex be named "vitamine".
Funk proposed the hypothesis that other diseases, such as rickets, pellagra, coeliac disease, and scurvy could also be cured by vitamins. Max Nierenstein a friend and reader of Biochemistry at Bristol University reportedly suggested the "vitamine" name from "vital amine". In , Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference, hence "vitamin," after researchers began to suspect that not all "vitamines" in particular, vitamin A have an amine component.
He called this "the anti-beriberi factor", which was later identified as vitamin B 1 , thiamine. In , Paul Karrer elucidated the correct structure for beta-carotene , the main precursor of vitamin A, and identified other carotenoids. For their investigations on carotenoids, flavins and vitamins A and B 2 , they both received the Nobel Prize in Chemistry in In , George Wald was awarded the Nobel Prize along with Ragnar Granit and Haldan Keffer Hartline for his discovery that vitamin A could participate directly in a physiological process.
Murphy , Alexander R. Todd , and Dorothy Hodgkin Once discovered, vitamins were actively promoted in articles and advertisements in McCall's , Good Housekeeping , and other media outlets. They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically-determined nutritional value, rather than taste or appearance.
Yoder is credited with first using the term vitamania , in , to describe the appeal of relying on nutritional supplements rather than on obtaining vitamins from a varied diet of foods. The continuing preoccupation with a healthy lifestyle has led to an obsessive consumption of additives the beneficial effects of which are questionable.
The term vitamin was derived from "vitamine", a compound word coined in by the Polish biochemist Casimir Funk   when working at the Lister Institute of Preventive Medicine. The name is from vital and amine , meaning amine of life, because it was suggested in that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This was true of thiamine , but after it was found that other such micronutrients were not amines the word was shortened to vitamin in English.
From Wikipedia, the free encyclopedia. Redirected from Vitamine. Nutrients required by organisms in small amounts. For other uses, see Vitamin disambiguation.Vitamin A. Vitamin A je naziv za skupinu spojeva koji su važni za vid, rast i razvoj, reprodukciju te staničnu diferencijaciju. Uključuje retinol, retinil estere, retinal i retinsku kiselinu (vitamin A1) te 3-dehidroretinol (vitamin A2). Najbolji izvor vitamina A je ulje jetre ribe, no nalazi se u voću i povrću u obliku provitamin A.