It was discovered in 1922 in vegetable oil given the name ‘tocopherol’. Vitamin E, of which there are four different forms, is fat soluble.
The four have the same name except with the prefixes alpha-, beta-, gamma-, and delta-, (the first four letters of the Greek alphabet).
Only alpha-tocopherol contributes toward meeting the human vitamin E requirement and it is the most common form of vitamin E in food.
It is our body’s major fat soluble antioxidant. It protects vulnerable polyunsaturated lipids in cell membranes, in blood and elsewhere throughout the body.
The richest dietary sources of vitamin E are the vegetable oils. Safflower and olive oil contain the highest proportion of alpha-tocopherol, followed by soybean oil.
Curiously enough, these oils are also the richest sources of polyunsaturated fatty acids, which vitamin E protects from oxidation.
Nuts and seeds such as sunflower seeds, are among the best food sources.
In western diet, vitamins E intake derives mainly from fats and oils contained in margarine, mayonnaise, salad dressing and desserts, and increasingly also from fortified food (e.g., breakfast cereals, milk, fruit juices).
Vitamin E helps reduce oxidation of lipid membranes and the unsaturated fatty acids and prevents the breakdown of other nutrients by oxygen.
Some scientists compare the function of vitamin E on the cell membrane to a lightening and nullifying the damage that occurs of lightening strikes. This function of vitamin E is also performed and enhanced by other antioxidants, such as vitamin C, beta-carotene, glutathione (L-cysteine), coenzyme Q and the mineral selenium.
In fact, there is a direct recycling process for vitamin E that requires the immediate presence of beta-carotene, vitamin C, flavonoids, and coenzyme Q to work.
Observational studies have suggested that high intake of antioxidant including vitamins E, may lower the risk of some chronic disease, especially heart disease.
Different forms of vitamin E, other than alpha-tocopherol, have immuno-regulatory functions,
Alpha-tocopherol is the most common form of vitamin E in plasma and tissues and the most extensively studied for its beneficial effect on immune function, probably because it is the exclusively component in most vitamin E supplements.
Vitamin E Sources and Functions
