Vitamin E

Vitamin E is a fat-soluble vitamin that exists in eight different forms. Alpha-tocopherol is the most active form of vitamin E in humans, and is a powerful biological antioxidant. Studies are underway to determine whether vitamin E might help prevent or delay the development of those chronic diseases.
What foods provide vitamin E?
Vegetable oils, nuts, and green leafy vegetables are the main dietary sources of vitamin E. Fortified cereals are also an important source of vitamin E in the United States. The table of selected food sources of vitamin E suggests foods that contain vitamin E.
What is the Recommended Dietary Allowance for vitamin E for adults?
The 2000 RDAs for vitamin E for adults, in International Units (IUs) are: 22 IU for men and women over age 19 including pregnant women, and 28 IU for lactating women.
The RDA for vitamin E is based on the alpha-tocopherol form because it is the most active, or usable, form.
When can vitamin E deficiency occur?
Vitamin E deficiency is rare in humans. A vitamin E deficiency is usually characterized by neurological problems due to poor nerve conduction.
Who may need extra vitamin E to prevent a deficiency?
Individuals who cannot absorb fat may require a vitamin E supplement because some dietary fat is needed for the absorption of vitamin E from the gastrointestinal tract.
Very low birth weight infants may be deficient in vitamin E . Abetalipoproteinemia is a rare inherited disorder of fat metabolism that results in poor absorption of dietary fat and vitamin E. Individuals with abetalipoproteinemia may be prescribed special vitamin E supplements by a physician to treat this disorder.
Current Issues and Controversies about Vitamin E
Vitamin E and heart disease
Preliminary research has led to a widely held belief that vitamin E may help prevent or delay coronary heart disease. Vitamin E may help prevent or delay coronary heart disease by limiting the oxidation of LDL-cholesterol. Vitamin E also may help prevent the formation of blood clots, which could lead to a heart attack.
Observational studies have associated lower rates of heart disease with higher vitamin E intake.
A study of approximately 90,000 nurses suggested that the incidence of heart disease was 30% to 40% lower among nurses with the highest intake of vitamin E from diet and supplements. The range of intakes from both diet and supplements in this group was 21.6 to 1,000 IU (32 to 1,500 mg), with the median intake being 208 IU (139 mg).
• A 1994 review of 5,133 Finnish men and women aged 30 - 69 years suggested that increased dietary intake of vitamin E was associated with decreased mortality (death) from heart disease. The researchers suggested that it is unlikely that the vitamin E supplement provided any protection against cardiovascular disease in the HOPE study.
Vitamin E and cancer
Antioxidants such as vitamin E help protect against the damaging effects of free radicals, which may contribute to the development of chronic diseases such as cancer.
Some evidence associates higher intake of vitamin E with a decreased incidence of prostate cancer and breast cancer. There is evidence that vitamin E may reduce the size of cysts in women with fibrocystic breast disease, which is a risk factor for breast cancer. However, an examination of the effect of dietary factors, including vitamin E, on incidence of postmenopausal breast cancer in over 18,000 women from New York State did not associate a greater vitamin E intake with a reduced risk of developing breast cancer.
A study of women in Iowa provided evidence that an increased dietary intake of vitamin E may decrease the risk of colon cancer, especially in women under 65 years of age. On the other hand, vitamin E intake was not statistically associated with risk of colon cancer in almost 2,000 adults with cancer who were compared to controls without cancer.
At this time there is limited evidence to recommend vitamin E supplements for the prevention of cancer.
Vitamin E and cataracts
Observational studies have found that lens clarity, which is used to diagnose cataracts, was better in regular users of vitamin E supplements and in persons with higher blood levels of vitamin E.
What is the health risk of too much vitamin E?
The health risk of too much vitamin E is low.
Even though this study provides evidence that taking a vitamin E supplement containing 530 mg or 800 IU for four months is safe, the long term safety of vitamin E supplementation has not been tested.
Some food sources of vitamin E
Vegetable oils, nuts, and green leafy vegetables are good dietary sources of vitamin E. Food manufacturers fortify many foods with vitamins and minerals. Almonds, dry roasted, 1 oz: 7.5 IU ~ 25% DV
Safflower oil, 1 Tb: 4.7 IU ~ 15% DV
Corn oil, 1 Tb: 2.9 IU ~ 10% DV
Turnip greens, frozen, boiled, 1/2 c: 2.4 IU ~ 8% DV
Mango, raw, 1 fruit: 2.3 IU ~ 8% DV
Peanuts, dry roasted, 1 oz: 2.1 IU ~ 8% DV
Kiwi, 1 medium fruit: 0.85 IU ~ 2% DV
Spinach, frozen, boiled, 1/2 c: 0.85 IU ~ 2% DV
•