Vitamins: vitamin supplements
Vitamins are a class of essential nutrients that cannot be synthesized (either at all or in sufficient quantities) by a given organism and must be taken (in trace quantities) with food for that organism's continued good health. Humans require 13 different vitamins. The term vitamin is not used for other classes of essential nutrients including dietary minerals, essential fatty acids or essential amino acids. Vitamins are complex organic substances that are needed in very small amounts for many of the processes carried out in the body. Usually only a few milligrams (mg) or micrograms (mg) are needed per day, but these amounts are essential for health. Most vitamins cannot be made by the body, so have to be provided by the diet, although vitamin D can be obtained by the action of sunlight on the skin, and small amounts of a B vitamin (niacin) can be made from the amino acid (tryptophan).
Vitamins are any of several organic substances that usually are separated into water-soluble (e.g., the B vitamins, vitamin C) and fat-soluble (e.g., vitamins A, D, E, K) groups. They are essential for our normal health and growth. The substances commonly known as vitamins are widely diverse in chemical structure and function. Originally defined as organic compounds, obtainable in a normal diet and capable of maintaining life and promoting growth, vitamins are distinct from carbohydrates, fats, and proteins in function, as well as in the quantities in which we require them. A number of compounds (e.g., choline, carnitine) once grouped with vitamins no longer are considered vitamins. In general, a vitamin essentially means something that must be included in our diet. If a vitamin is absent from our diet or is not properly absorbed, a deficiency disease specific to that vitamin may ensue.
The term vitamin originated from “vitamine,” a word first used in 1911 to designate a group of compounds considered vital for life; each was thought to have a nitrogen-containing component known as an amine. The final e of vitamine was dropped when it was discovered that not all of the vitamins contain nitrogen, and, therefore, not all are amines. There is not uniform agreement concerning our vitamin requirements. Differences in opinion arise mainly from different ways by which requirements can be determined and from the scanty data available for the requirements for some of the vitamins. Recommended daily allowances (RDA) are useful guides to knowing how much vitamins you need. However, several factors for examples, genetic variation; presence of specific disease states; therapeutic use of certain drugs; infestation with parasites; relative proportions of other dietary constituents, food additives, or contaminants; environmental stresses; and stimulation of growth rate, can affect how much vitamins we need at any particular time.
Vitamins are not only necessary for our health and well-being, vitamins and minerals will prevent diseases associated with nutritional deficiencies such as scurvy, beriberi, pellagra and rickets, give us healthy bones and teeth, prevent us going blind, and from being prone to unexpected bleeding. Vitamins also protect our hearts from damage, and protect us against cancer. Recent research evidence also suggests that vitamin C and E combined in high doses helps reduce our risk of developing Alzheimer’s disease.
Vitamins are organic chemical compounds that occur naturally in certain foods. There are thirteen different vitamins and your body must have all thirteen to function properly. Vitamins promote normal growth, provide proper metabolism (energy in your cells), ensure good health and protect against certain diseases. As the building blocks for the majority of chemical reactions in your body, vitamins combine with proteins and minerals to produce enzymes (which speed up your internal chemical reactions) and hormones (which regulate organ functions and activities including heart rate, blood pressure and glucose levels.)
There are two groups of vitamins: ones that are fat-soluble and others that are water-soluble. Fat-soluble vitamins such as A, D, E and K can be stored in your body - mostly in fatty tissue and in the liver. Because your body can store these vitamins, you don't need to ingest them everyday for good health. But since they are stored, there is a danger in getting too much of them and they can build to toxic levels in the body. Water-soluble vitamins like C and the Bs, on the other hand, do not stay in the body long. Since they dissolve in water, any trace of the vitamins that your body doesn't need will be carried away in wastes. It is essential to receive a healthy supply of these vitamins everyday. Except in cases of massive overdosing, water-soluble vitamins can rarely reach toxic levels.
Vitamins are sometimes referred to as the "spark plugs" of our human machine. They are required to do many things and their excess or depletion can lead to acute and chronic disease. This is why understanding the vitamins is important in healthy aging. The vitamins are categorized into two groups: 1) fat-soluble (vitamins A,D,E, K) and 2) water soluble (vitamins B,C, P). The difference is important because the water soluble vitamins are excreted by the kidneys and it is particularly important to be certain that they are present in our daily consumption. On the other hand the fat soluble vitamins are stored in fat and other tissues and if we ingest too much they can accumulate and Vitamin A in particular is known to be toxic. Only vitamins D and K are produced by the body and the others must be either in the food we eat or in a supplemental pill or capsule. Vitamin A, vitamin C, and vitamin E are anti-oxidants and data shows they can help prevent cardiac disease and some cancers.
The amount of vitamins required everyday is exceptionally small and a varied diet generally provides enough of each vitamin and mineral. However, some people don't eat a varied diet, or their lifestyle or medical condition prevents their body from using the nutrients they do eat. In other cases, extra physical demands (such as those of pregnancy) mean that even a highly nutritious diet can sometimes fall short. Supplements may also be useful to correct deficiencies of particular vitamins or minerals. They can also help to reduce the risk of deficiency in people who are lactose intolerant or allergic to milk.