Vitamin E is an essential nutrient that has antioxidant properties and plays many important roles in the body. It actually refers to a group of compounds rather than a single substance. The most common form found in supplements is alpha-tocopherol.
Other Names for Vitamin E
There are several alternate names used to refer to vitamin E including:
- Tocopherol – This is the chemical name for the various forms of vitamin E including alpha-tocopherol, beta-tocopherol, gamma-tocopherol, and delta-tocopherol.
- Alpha-tocopherol – This is the most active form of vitamin E found in the body and in most supplements.
- Tocotrienol – Along with tocopherols, this is one of the two main vitamin E family groups. Tocotrienols have a similar molecular structure but with differences in the side chain.
- d-Alpha-tocopherol – This refers specifically to the natural form of alpha-tocopherol that is found in food and the body. The “d” stands for dextrorotatory and refers to its molecular structure.
Some other common names for vitamin E used in the supplement industry include:
- Acetate – Vitamin E in the acetate form has acetic acid bound to it to improve stability.
- Succinate – This ester form is created by binding succinic acid to vitamin E to also help stabilize it.
- Mixed tocopherols – This refers to a supplement containing multiple natural vitamin E compounds, not just alpha-tocopherol.
Background on Vitamin E
Vitamin E is a fat-soluble vitamin that was first discovered in 1922 by researchers Herbert Evans and Katherine Bishop. It was initially called “factor X” due to its unknown nature. The vitamin was isolated over the next several years and by 1936 it was named tocopherol from the Greek words “tokos” meaning childbirth and “pherin” meaning to bring forth, due to its importance for reproduction.
In 1968, the eight natural compounds were named alpha-, beta-, gamma-, and delta-tocopherol and alpha-, beta-, gamma-, and delta-tocotrienol. The “ol” at the end of tocopherol refers to the alcohol form of the compounds. Synonyms like tocopheryl or tocopherolic are also sometimes used.
Forms of Vitamin E in the Body
While there are eight natural forms of vitamin E, alpha-tocopherol is the most abundant in the human body and has the highest biological activity. Next most common are gamma-tocopherol and delta-tocopherol. The tocotrienol forms of vitamin E are less common in tissues.
Here are the key characteristics of the main vitamin E compounds:
- Alpha-tocopherol – Most bioavailable and active form. Highest antioxidant activity.
- Beta-tocopherol – Lower antioxidant activity than alpha-tocopherol.
- Gamma-tocopherol – Important scavenger of reactive nitrogen species.
- Delta-tocopherol – Believed to have the highest anti-inflammatory properties.
|Vitamin E Form||Key Characteristics|
|Alpha-tocopherol||Most bioavailable and active form. Highest antioxidant activity.|
|Beta-tocopherol||Lower antioxidant activity than alpha-tocopherol.|
|Gamma-tocopherol||Important scavenger of reactive nitrogen species.|
|Delta-tocopherol||Believed to have the highest anti-inflammatory properties.|
Biological Functions of Vitamin E
As a fat-soluble antioxidant, vitamin E helps protect cell membranes from oxidative damage caused by free radicals. It works synergistically with vitamin C to regenerate other antioxidants like glutathione. Some of the key functions of vitamin E include:
- Preventing lipid peroxidation – Protects polyunsaturated fatty acids in cell membranes and lipoproteins from damage.
- Inhibiting the formation of nitrosamines – Nitrosamines are compounds that can cause DNA damage.
- Immune support – Boosts immune response and increases resistance to infection.
- Anti-inflammatory activity – Reduces markers of inflammation.
- Cell signaling – Modulates cell signaling pathways involved in inflammatory response.
Vitamin E also plays a role in eye health, neurological function, and blood vessel dilation. The recommended daily intake for adults is 15 mg of alpha-tocopherol or 22.4 IU.
Vitamin E Deficiency
Vitamin E deficiency is rare in healthy people. It can occur in those with fat malabsorption conditions like cystic fibrosis, chronic cholestasis, or abetalipoproteinemia. Premature and very low birth weight infants are also at higher risk.
Mild deficiency may not cause any obvious symptoms initially. More severe deficiency can lead to nerve problems like peripheral neuropathy, muscle weakness, vision issues, and impaired immune function.
Food Sources of Vitamin E
The best way to obtain vitamin E is through food sources. The highest dietary sources include:
- Vegetable oils (wheatgerm, sunflower, safflower, corn, soybean)
- Nuts and seeds (almonds, peanuts, hazelnuts, pine nuts)
- Green leafy vegetables (spinach, broccoli, lettuce)
- Fortified cereals and spreads
- Fish (rainbow trout, salmon)
- Avocados and olives
Since vitamin E is fat-soluble, consuming these foods along with a source of dietary fat can help increase absorption.
In summary, vitamin E is a generic term used for a group of eight naturally occurring compounds known as tocopherols and tocotrienols. The most biologically active form that is found abundantly in the body and supplements is alpha-tocopherol. Other names like tocopheryl, tocopherolic, and d-alpha-tocopherol are also used to refer specifically to the natural form of this nutrient.
As an antioxidant, vitamin E helps protect cells from oxidative stress and is involved in important processes like immune function and blood vessel dilation. Deficiency is rare but can lead to neurological problems and impaired immunity. The best dietary sources are oils, nuts, seeds, vegetables, and fish.