VITAMINS are very essential for our body , they help in development and maintenance of our body therefore we must know about them because they are to be taken in our proper natural diets , we should choose our food carefully so that it can give us full benefit. Vitamins when used as medicine and food supplement must be taken in medical guidance and supervision only.
VITAMIN is an organic compound required as a nutrient in tiny amounts by an organism.[ The term 'vitamin' first became popular in the early 1800's as a contraction of the words 'vital' and 'mineral', though the actual meaning of the word has developed somewhat since that time[. A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and the particular organism. For example, ascorbic acid functions as vitamin C for some animals but not others, and vitamins D and K are required in the human diet only in certain circumstances. The term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids, nor does it encompass the large number of other nutrients that promote health but are otherwise required less often.
VITAMINS are classified by their biological and chemical activity, not their structure. Thus, each "vitamin" may refer to several vitamer compounds that all show the biological activity associated with a particular vitamin. Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A", which includes the compounds retinal, retinol, and four known carotenoids.[5] Vitamers are often inter-converted in the body.
Vitamins are classified as either water-soluble or fat soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water, and in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.[ Because they are not readily stored, consistent daily intake is important. Many types of water-soluble vitamins are synthesized by bacteria.[ Fat-soluble vitamins are absorbed through the intestinal tract with the help of FATS( LIPIDS) Because they are more likely to accumulate in the body, they are more likely to lead to hyper vitaminosis than are water-soluble vitamins. Fat-soluble vitamin regulation is of particular significance in cystic fibrosis.
List of vitamins—Vitamin A ,BI, B2,B3,B5, B6, B7,B9, B12, Vitamin C, VIT. D, VIT. E, VIT. K.
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In nutrition and diseases
Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, it can cause deficiency in the body also.
For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of the natural ultraviolet wavelength of sunlight there fore sun light is essential for us. Humans can produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan.
Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for respiration.
Deficiencies
Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency. Human bodily stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts in the human body, mainly in the liver, and an adult human's diet may be deficient in vitamins A and B12 for many months before developing a deficiency condition. Vitamin B3 is not stored in the human body in significant amounts, so stores may only last a couple of weeks. Deficiencies of vitamins are classified as either
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primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a “lifestyle factor”, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases.
Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy) and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food; and (2) the addition of vitamins and minerals to common foods, often called fortification. In addition to these classical vitamin deficiency diseases, some evidence has also suggested links between vitamin deficiency and a number of different disorders.
Side effects and overdose
In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting.
When side effects emerge, recovery is often accomplished by reducing the dosage. The concentrations of vitamins an individual can tolerate vary widely, and appear to be related to age and state of health. In the United States, overdose exposure to all formulations of vitamins was reported by 62,562 individuals in 2004 (nearly 80% of these exposures were in children under the age of 6), leading to 53 "major" life-threatening outcomes and 3 deaths; a small number in
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comparison to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004).
Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some vitamin supplements is well established for certain health conditions, but others need further study. In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions. Dietary supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.[
Governmental regulation of vitamin supplements---
Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Unlike drug products, which must explicitly be proven safe and effective for their intended use before marketing, there are often no provisions to "approve" dietary supplements for safety or effectiveness before they reach the consumer. Also unlike drug products, manufacturers and distributors of dietary supplements are not generally required to report any claims of injuries or illnesses that may be related to the use of their products these products fully commercialized without thinking about common people who are targets of vigorous marketing strategy.
In the concluding part of this semi technical article general public is advised not take vitamins unnecessarily and without medical advice, too much any useful thing is waste of money also because these vitamins and dietary supplements are not cheep.
