Vitamin E is the name given to a group of eight chemicals with similar properties that are essential to health. Vitamin E was first isolated as a distinct substance in various green leafy vegetables in 1922. Vitamin E is classed as a micronutrient, a substance that is not required in large quantities through diet but which is otherwise essential to the maintenance of good health. In all of its forms, vitamin E is an organic (carbon-based) compound, of which alpha tocopherol is the most prolific. Vitamin E is often referred to as nature's antioxidant, a testament to the important function of these chemicals within the body.
Vitamin E, as with all micronutrients, is required in trace amounts for bodily function. The recommended daily requirement for adults of this substance is 15 mg per day. The consumption of dietary supplements to ensure the ingestion of the required quantities of vitamin E is unnecessary if the person is consuming a well-balanced diet, as the best sources of the chemical are commonly available food products, such as wheat and its large number of byproducts, many green leafy vegetables, and most nuts, seeds, and their oils. Vitamin E is the least toxic of all fat-soluble vitamins; the recommended upper daily limit of vitamin E consumption is 1,000 mg.
Vitamin E is a fat-soluble compound. It is processed for entry into the body at the small intestine, where the vitamin is parceled into chemical packages made from both high density lipoproteins (HDLs) and low density lipoproteins (LDLs) to facilitate the absorption of vitamin E into both the lymphatic system and the liver. From these locations, vitamin E then is released directly into the bloodstream.
With either its HDL or LDL transportation in the bloodstream, vitamin E is carried to various cells within the body. As a fat-soluble vitamin, vitamin E can be stored within the cell mitochondria (often described as the cellular powerhouse) of the adipose tissue, the cells designed for the storage of triglycerides (fats), for an indefinite period. Once utilized as an antioxidant, the spent vitamin E is disposed of by the body through the stomach bile; it is ultimately excreted from the body as feces.
Oxidation is a biological concept that is readily understood with reference to many daily life examples. Rusted metal, food that turns rancid, and the various aging processes observable within the body are examples of oxidation, which is the decay or the degradation of a cell due to the effect of oxygen. An antioxidant, such as vitamin E, is any substance that by its presence or its operation, serves to specifically delay, prevent, or reverse the rate of deterioration caused in the cells by oxygen. Antioxidants are classed as one of two types: metal sequestrants, which prevent metals from reacting with oxygen, and free radical scavengers, which operate to interrupt the destructive chain reactions that occur within the body that are precipitated by the compounds known as free radicals. Vitamin E and, in certain circumstances, vitamin C, are free radical scavengers within the body.
Free radicals are the most common cause of oxidation within the body. Occurring throughout the body, these chemical compounds are inherently unstable, as their electron structure is unbalanced due to one or more electrons within the structure not being paired, which creates either a positive or negative electric charge within the free radical. The free radical therefore seeks to obtain the necessary electrons to create electrical balance from nearby stable compounds. This "theft" of electrons by the free radicals renders the previously stable compound unstable and reactive. This use precipitates a chain reaction of electron use that is the essence of the oxidation that causes cell damage.
As an antioxidant, vitamin E traps the free radicals that it encounters, through its donation of a hydrogen atom to the free radical molecule, rendering it chemically neutral. Vitamin E ranges throughout the tissues of the body, and it provides its antioxidant benefits to all aspects of the cardiovascular and musculoskeletal systems. Vitamin E does not differentiate between the types of free radicals it may encounter, nor does vitamin E restrict its actions based on the place of origin of the target free radical.
There is no question from a scientific perspective that vitamin E is a very important compound within the body, as it protects the tissues from decay and degradation. The companion issue of whether megadoses of vitamin E, by daily supplement or otherwise, will provide enhanced health protection has not been conclusively determined. The actions of vitamin E must also be considered separately from the healing and repair of tissue that occurs within the body. Antioxidant function is separate from the cell repair that occurs within the body at all cell production points—bone, connective tissue, muscles, and blood cells may be degraded by the actions of free radicals. Vitamin E does not play a role in cell production.