Vitamin E has an important role in cell metabolism and its deficiency can affect multiple organ systems. It works with other nutrients and factors like selenium and vitamin C to protect against reactive oxygen species. The most biologically potent form is alpha-tocopherol, found naturally in plant oils and green plants. While animal tissues contain low amounts, the highest levels are in fatty tissues. Dietary sources of vitamin E include vegetable oils, seeds, and cereal grains, with wheat germ oil providing the most.

1. Domina Petric, MD
Significance and sources of vitamin E

2. Significance of vitamin E
• Vitamin E has a fundamental role in the normal
metabolism of all cells.
• Its deficiency can afffect several different organ
systems.
• Its function is related to those of several other
nutrients and endogenous factors that, collectively,
comprise a multicomponent system that provides
protection against the potentially damaging effects
of reactive species of oxygen formed during
metabolism or that are encountered in the
environment.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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3. Significance of vitamin E
• Both the need for vitamin E and the
manifestations of its deficiency can be
affected by such nutrients as selenium and
vitamin C and by exposure to such prooxidant
factors as polyunsaturated fatty acids (PUFAs),
air pollution and ultraviolet (UV) light.
• Vitamin E may also have non antioxidant
functions in regulating gene expression and
cell signaling.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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4. Significance of vitamin E
Supranutritional levels of the
vitamin have been useful in
reducing the oxidation of low
density lipoproteins (LDLs) and
thus reducing the risk of
atherosclerosis.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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5. Sources of vitamin E
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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6. Distribution in food
• Vitamin E is synthesized only by plants.
• It is found primarily in plant products, the richest
sources being plant oils.
• All higher plants appear to contain α-tocopherol in
their leaves and other green parts.
• Because α-tocopherol is contained mainly in the
chloroplasts of plant cells (whereas the β-, γ- and
δ-vitamers are usually found outside of these
particles), green plants tend to contain more vitamin
E than yellow plants.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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7. Distribution in food
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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8. Distribution in food
Animal tissues tend to contain low amounts
of α-tocopherol, the highest levels occurring
in fatty tissues.
Because vitamin E occurs naturally in fats and
oils, reductions in fat intake can be expected
also to reduce vitamin E intake.
A water-soluble metabolite, α-tocopheryl
phosphate, has also been idenfied at trace
levels in animal tissues.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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9. Vitamin A activity
The most biopotent vitamer-the
vitamer of greatest interest in
nutrition is α-tocopherol, which
occurs naturally as the RRR
stereoisomer [(RRR)-α-
tocopherol].
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
9

10. Synthetic forms
• Synthetic preparations of vitamin E are
mixtures of all eight diastereoisomers, that is,
2RS, 4′RS, 8′RS-vitamers designated more
commonly with the prefix all rac- in both
unesterified (all-rac-α-tocopherol) and
esterified (all-rac-α-tocopheryl acetate) forms.
• Other forms used commercially include all-rac-
α-tocopheryl succinate and all-rac-α-tocopheryl
polyethyleneglycol-succinate.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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11. Dietary sources of vitamin E
• The important sources of vitamin E in human
diets and animal feeds are vegetable oils and,
to lesser extents, seeds and cereal grains.
• The dominant dietary form is γ-tocopherol.
• Wheat germ oil is the richest natural source,
containing 0.9 to 1.3 mg of α-tocopherol per
gram, or, about 60% of its total tocopherols.
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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12. Dietary sources of vitamin E
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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13. • Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
Literature
4/10/2018
Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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