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Overview |
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Vitamin E is an important antioxidant which protects cells from free radical
damage, thereby prolonging cell life and slowing the aging process. Research has
shown this nutrient plays a vital role in the prevention and treatment of
cardiovascular disease, cancer, immune system disorders, and aging-related
degenerative diseases.
Three major clinical studies (The Nurses' Health Study, The Physicians'
Health Study, and a study done by the University of Texas Southwestern Medical
Center) have provided evidence supporting the benefits of vitamin E
supplementation in the prevention of heart disease. Vitamin E blocks the
oxidation of LDL cholesterol, thereby reducing arterial damage and plaque
formation. A study at the University of South Carolina School of Medicine showed
that 100 IU of vitamin E daily actually may have reversed arterial blockage. A
World Health Organization study showed that supplemental vitamin E was more
likely to prevent fatal heart attacks by lowering blood cholesterol, presumably
because it prevents oxidation of cholesterol into its most toxic form.
Vitamin E has long been recognized as an anticlotting agent, thereby reducing
risk of heart attack and stroke. Studies have shown vitamin E's important role
in cancer prevention and in the benefits of use during cancer treatment. Animal
and human studies have concluded that the nutrient blocks the initiation of
carcinogenesis and reduces the incidence of skin, oral, stomach, colon, and
breast cancer. Other studies have suggested that vitamin E may also reduce the
risk of lung, esophageal, and cervical cancer. Researchers have found that
during cancer treatment, vitamin E supplementation protects normal cells from
the damaging effects of chemotherapy without protecting the cancer cells, which
reduces side effects without reducing efficacy. New research suggests that
vitamin E interferes with oxygen-controlled signals which promote cancer cell
growth.
The most recent studies have shown vitamin E supplementation may reduce the
incidence of prostate cancer, reverse diabetic neuropathy in Type II diabetics,
may increase/improve insulin's effect in Type II diabetes, and significantly
improve immune status in aging adults. Preliminary research suggests the
nutrient may slow or prevent the progress of degenerative brain
diseases. |
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Dietary Sources |
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Food sources of vitamin E include wheat germ oil, margarine, soybean oil,
almonds, safflower oil, hazelnuts, corn oil, peanuts, cottonseed oil, walnuts,
canola oil, mayonnaise, sunflower seeds, spinach, kale, sweet potatoes, and
yams.
Vitamin E is destroyed when vegetable oils are processed and bleached; only
cold-pressed vegetable oils are a good source. Wheat germ oil is the richest
source of natural vitamin E. |
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Constituents/Composition |
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Vitamin E occurs in several forms with varying biologic activity.
Alpha-tocopherol is the most common, most potent, and best absorbed form. Other
forms include beta-, delta-, and gamma-tocopherol, and
alphatocotrienol. |
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Commercial
Preparations |
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Supplemental vitamin E is available in both natural and synthetic forms.
- Natural vitamin E (d-alpha-tocopherol) has been the preferred form,
and it is available with mixed tocopherols added.
- The synthetic form is dl-alpha-tocopherol.
- Standard preparations are available in 50 IU, 100 IU, 200 IU, 400 IU,
500 IU, 600 IU, and 1,000 IU softgels, tablets, and capsules.
- Vitamin E succinate ("dry-E") is water soluble and best tolerated by
those with fat malabsorption syndromes.
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Therapeutic Uses |
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Vitamin E may have the following therapeutic effects.
- Slows the aging process of all cells/tissues
- Protection against environmental pollutants and toxins
- Protects integrity of red blood cells and aids in prevention of
hemolytic anemia
- Supplementation indicated for all fat malabsorption disorders,
including celiac disease, tropical sprue, cystic fibrosis, and pancreatic
disease
- Indicated for use in the treatment of most skin disorders, e.g.,
acne, eczema, psoriasis
- Prevention against atherosclerosis or its progression by helping
reduce/reverse plaque formation
- Prevents oxidation of LDL cholesterol
- Improves arterial response when atherosclerosis is present
- Reduces tissue damage associated with ischemia during heart surgery;
indicated for use before and after any surgery
- Promotes proper wound healing
- Anticlotting agent useful in prevention of pulmonary embolism,
thrombosis, and stroke; indicated for use for angina, atherosclerosis,
intermittent claudication, and for women using hormonal
contraceptives
- Aids in prevention of cataracts and macular degeneration
- Indicated for use in all reproductive disorders
- Reduces symptoms associated with premenstrual syndrome
- Effective against fibrocystic breast disease
- Protects against initiation of carcinogenesis
- Indicated for use in cancer prevention and treatment
- May slow progression of mental deterioration associated with
Alzheimer's, degenerative, or arteriosclerotic brain disease
- Significantly improves age-related immune response
dysfunction
- Indicated for use in Type II diabetes
- Significantly decreases symptoms of lupus erythematosus with dose of
1,200 IU/day
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Dosage Ranges and Duration of
Administration |
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Recommended dietary allowances (RDAs) are as follows.
- Neonates to 6 months: 4 IU
- Infants 6 months to 1 year: 6 IU
- Children 1 to 3 years: 9 IU
- Children 4 to 10 years: 10 IU
- Children over 10 years and adults: 12 IU for females, 15 IU for
males.
Note: 1 mg vitamin E equals 1.5 IU.
Based on clinical trials, the recommended dose for disease prevention and
treatment for adults is 400 to 800 IU/day. |
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Side
Effects/Toxicology |
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Vitamin E is relatively nontoxic. Adverse effects which may occur with very
high doses (more than 1,200 IU/day) include nausea, flatulence, diarrhea, and
heart palpitations. |
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Warnings/Contraindications/Precautions |
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- Increased blood pressure. Individuals with hypertension may show an
increase in blood pressure if starting dose is too high. Recommendation is for
initial dose of 100 IU/day, increasing as tolerated up to 400 IU/day with
monitoring as dosage is increased.
- Prolonged bleeding time
- High doses of vitamin E may interfere with vitamin K activity.
- Caution with warfarin use
- Extreme doses (more than 800 IU) over time may have detrimental
effects, although toxicity per se has not been
documented.
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Interactions |
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Aspirin
A double-blind, randomized study evaluated the interaction between an
antiaggregating agent with vitamin E in 100 patients at risk for transient
ischemic attacks (TIAs) (Steiner et al. 1995). Patients were administered either
aspirin (325 mg) or aspirin plus vitamin E (400 IU/day) for two years. The group
receiving combination therapy had a significant reduction in ischemic events and
platelet adhesiveness. However, the incidence of hemorrhagic stroke was not
affected by treatment. The combination of vitamin E and aspirin appears to be
safe and may benefit patients at risk for
TIAs. Chloroquine
Phosphate
Vitamin E inhibits drug uptake in a dose-dependent manner in human cultured
fibroblasts exposed to single and repetitive doses of chloroquine and other
cationic amphiphilic drugs (Scuntaro et al. 1996). Cationic amphiphilic drugs
encompass a variety of therapeutic classes of medications including
antiarrhythmics, antidepressants, and
neuroleptics. Chlorpromazine
Vitamin E inhibits drug uptake in a dose-dependent manner in human cultured
fibroblasts exposed to single and repetitive doses of chlorpromazine and other
cationic amphiphilic drugs (Scuntaro et al. 1996). Cationic amphiphilic drugs
encompass a variety of therapeutic classes of medications including
antiarrhythmics, antidepressants, and
neuroleptics. Cyclosporine
A study with ten healthy subjects evaluated the interaction between
water-soluble vitamin E and cyclosporine (Chang et al. 1996). After two doses of
cyclosporine (10 mg/kg po), oral vitamin E was randomly administered with the
drug. Concomitant administration of vitamin E and cyclosporine significantly
decreased the clearance and steady-state volume of distribution for the drug.
The combination therapy increased the area under the curve (AUC) for
cyclosporine. The increased AUC may be the result of enhanced bioavailability.
However, a subsequent in vitro study suggested that vitamin E and cyclosporine
antagonize one another (Van Rensburg et al. 1998).
Desipramine
Vitamin E inhibits drug uptake in a dose-dependent manner in human cultured
fibroblasts exposed to single and repetitive doses of desipramine and other
cationic amphiphilic drugs (Scuntaro et al. 1996). Cationic amphiphilic drugs
encompass a variety of therapeutic classes of medications including
antiarrhythmics, antidepressants, and
neuroleptics. Estradiol
Preliminary findings indicate that hormone replacement therapy (HRT) may
preserve the content of vitamin E in LDL particles that, in turn, reduce the
amount of oxidized LDL (Clemente et al. 1996). Concomitant administration of
vitamin E with transdermal estradiol was shown to improve LDL, HDL, and total
cholesterol status in postmenopausal women (Inal et al. 1997). Most studies
showing a benefit from vitamin E on heart disease risk have used quantities of
vitamin E (400 to 800 IU/day) that are much higher than RDA values (Emmert and
Kircher 1999).
Gemfibrozil
There are conflicting reports regarding the effect of gemfibrozil on vitamin
E status in hyperlipidemic patients. In one study, gemfibrozil treatment in men
with combined hyperlipidemia reduced serum ubiquinone-10 and gamma- and
alpha-tocopherol levels (Aberg et al. 1998). In another study, gemfibrozil had
no effect on vitamin E status and increased the LDL vitamin E/lipid peroxide
ratio concentrations (Yoshida et al.
1998). HMG-CoA
Reductase Inhibitors
HMG-CoA reductase therapy may decrease the antioxidant capacity of vitamin E
on LDL cholesterol (Palomaki et al. 1998). However, coadministration of vitamin
E (300 IU) with simvastatin (20 mg) improved markers of blood vessel elasticity
in hypercholesterolemic patients more than simvastatin monotherapy (Neunteufl et
al. 1998). Similar benefits may be observed with fluvastatin and other HMG-CoA
reductase
inhibitors. Oral
Contraceptives
Oral contraceptives reduce some of the vitamins and enzymes involved in the
oxidative defense system (Ciavatti and Renaud 1991; Tangney and Driskell 1978).
Impaired antioxidant status can increase the susceptibility to lipid
peroxidation and possibly thrombosis in women (Ciavatti and Renaud 1991). Some
of these effects can be counteracted by vitamin E
supplements. Propranolol
Vitamin E inhibits drug uptake in a dose-dependent manner in human cultured
fibroblasts exposed to single and repetitive doses of propranolol and other
cationic amphiphilic drugs (Scuntaro et al. 1996). Cationic amphiphilic drugs
encompass a variety of therapeutic classes of medications including
antiarrhythmics, antidepressants, and
neuroleptics. Verapamil
An in vitro study suggested that vitamin E antagonized the chemosensitizing
effects of verapamil (Van Rensburg et al. 1998). Tests performed using the human
small cell lung cancer line demonstrated that the inclusion of alpha-tocopherol
(25 mcg/mL) prevented the ability of verapamil (2 mcg/mL) to sensitize the cells
to the effects of doxorubicin and
vinblastine. Warfarin
Vitamin E does not appear to enhance the pharmacologic effects of warfarin
(Kim and White 1996). However, the administration of high doses of vitamin E to
individuals with reduced levels of vitamin K may potentiate a vitamin K
deficiency and increase the anticoagulant effect of warfarin (Corrigan 1982).
Although the mechanism of this interaction is unclear, vitamin E may affect the
carboxylation of prothrombin, a vitamin-K-dependent step in the production of
coagulation factors.
Zidovudine
Antiviral activity and bone marrow toxicity of zidovudine (AZT) were
evaluated in the presence of water-soluble vitamin E (alpha-D-tocopherol acid
succinate (ATS)) in two cell test systems (Gogu et al. 1989). In the MT4 cell
line, ATS displayed a dose-dependent increase in anti-HIV activity that was six
times greater than when AZT was also administered. In addition, vitamin E showed
significant protection against AZT-induced toxicity in murine bone marrow
cells. |
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References |
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serum ubiquinone and alpha- and gamma-tocopherol levels in men with combined
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Balch J, Balch P. Prescription for Nutritional Healing: A-to-Z Guide to
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Chan AC. Vitamin E and atheroschlerosis. J Nutr.
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Chang T, Benet LZ, Hebert MF. The effect of water-soluble vitamin E on
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Steiner M, Glantz M, Lekos A. Vitamin E plus aspirin compared with aspirin
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Tangney CC, Driskell JA. Vitamin E status of young women on combined-type
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
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The reader is advised to check product information (including package inserts)
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interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. | |