The compounds known as vitamins are essential for human nutrition. Vitamins are considered micronutrients as the human body requires only small amounts at any given time. The class of compounds called vitamins is a group of organic compounds - they are called vitamins from the mistaken assumption that they are all amines, this was found to be false and vitamins are now known to belong to several different types of compounds. All kinds of vitamins can be found in plants and animals. One major function of vitamins is as coenzymes in enzymatic catalysis and enzyme system reactions. The class of compounds known as enzymes are biochemical catalysts or reaction activators important in all the chemical reactions that occur on a continual place in the human body. Many enzymes have different kinds of vitamins as a fundamental part of their structure. Some kinds of vitamins also perform other functions and role in addition to their role as coenzymes. The essential vitamin E has the role of an antioxidant in the body, while the vitamin D has a hormone like role. Once they are absorbed into the body, the vitamins are assimilated into the body becoming parts of the cells, part of enzymes and hormones, as well as becoming part of the muscles, the blood and the bones. The length of residence of the vitamins in the body is different for various vitamins. Some types of vitamins are utilized over a long period of time, while some vitamins are utilized as soon as they are assimilated. There are two major groups of the vitamins, the first are known as the water-soluble vitamins - these vitamins have short residence times in the human body, the second group is the fat-soluble vitamins - this class of compounds stays for longer periods of time in the body.
Certain other class of substances is also occasionally considered to be essential vitamins for human beings. However, the status of vitamin has not been applicable to them and the status of vitamin has not been established for these compounds. Compound that are considered at par with vitamins are: para-aminobenzoic acid (PABA), the compound choline; the lipoic acid; the compound inositol; ubiquinone or coenzyme Q10, plant based pigments called bioflavonoids and the compound called L-carnitine. Some of these compounds have been found to have vitamin like activity in some animals other than human beings.
While there is knowledge about the many biochemical and physiological roles that all the vitamins play in the body, we still do not know everything that there is to know about them and their mode of operation. For example, there is great difficulty in connecting the biochemical functions and physiological roles of most vitamins with their deficiency states. There is a possibility that man new roles played by vitamins in the human body will be discovered and it has been anticipated that most vitamins will continue to prove to be rich grounds for both basic and clinical investigators. The fact is that we may not even be aware of the existence of some compounds that should be classed as vitamins.
There are many situations in which a person is at risk for suffering from a deficiency of any vitamin, even though the regular consumption of a well balanced nutritious diet is still believed by some to sufficiently supply all the vitamins and minerals that humans need in good enough quantities to maintain good health in a person. There are many groups of people who can be considered susceptible to a deficiency of some vitamins, included in these risk groups are people who are on long term low calorie diets, all alcoholics and pregnant women also tend to suffer from some form of vitamin deficiency, the elderly and the aged generally are at a greater risk of vitamin deficiency, as are surgical patients and users of certain medications as well as strict vegetarians and vegans.
The trend in recent times is a greater tendency to use vitamins in mega dose amounts - this is dosage that is greater than ten times the RDA - certain classes of vitamins are taken in such amounts for several reasons and by specific classes of people. Such doses are usually taken to help protect against the effect of colds, to help a person cope with the stresses of daily life, to increase the sexual prowess and libido among other things. The case against the use of mega doses of each vitamin will be given here along with the analysis of each single vitamin. At the same time, certain pathological states and conditions affected the body are often treated using defined indications for the use of mega dosages of specified vitamins as pharmaceutical agents, however, the use of mega doses even in these situations will require the supervision of a qualified nutritionally oriented physician. Some of the pathological conditions that require mega dosages include using large amounts of the vitamin - nicotinic acid to lower blood cholesterol levels in people affected by blood cholesterol elevation. The use of mega doses of the vitamin A and synthetic vitamin A derivatives to treat certain skin disorders. The prevention of seizures induced by an overdose of INH by use mega doses of the vitamin B6 - INH is a medication commonly prescribed for the tuberculosis' treatment.
Supplementation with vitamins is supported by the slow accumulation of primary scientific evidence that suggests that even the most well fed individuals on a balanced diet can profit in the long term as such supplements optimize health and have long lasting benefits - taking vitamin supplements in optimum doses is ideal for all people. Certain vitamins also work as antioxidants in addition to their primary role in the cellular level metabolism; these vitamins can protect all the tissues against toxic damage inflicted from free molecular oxygen at the cellular level. An antioxidant action displayed by these vitamins gives the body protection against cell level damage and establishes a major preventive role for the vitamins in fighting off several major degenerative diseases and disorders that affect human beings.
In times of illness, the amount of vitamins the body needs greatly increases. This increase is also felt in the period following surgery, vitamin requirement increases as a result of the normal aging process as well. Vitamin supplementation may be required under such circumstances to meet the body's increased needs or to actively prevent the symptoms of a deficiency in select nutrients - vitamins are also lost from the body due to a variety of factors and these may need to be replenished via supplementation.
A good nutritious and well balanced diet cannot be replaced by mere vitamin supplements. While essential to life, the vitamins themselves do not provide any energy to the body. Vitamins are just one essential component of the human diet and the body requires a lot of other substances besides vitamins for a full and adequate nutritional status, these include carbon based compounds like the carbohydrates, the fats and other lipids, the proteins and all essential trace minerals. The health of the human body is not sustainable by vitamins alone and all other vital nutrients, such as minerals are required primarily from the food consumed by a person.