Food Supplements and Vitamins. Vitamin E

Vitamin-E-Prostate

Background

Vitamin E is a fat-soluble vitamin with antioxidant properties. Vitamin E exists in eight different forms (isomers): alpha-, beta-, gamma-, and delta-tocopherol; and alpha-, beta-, gamma-, and delta-tocotrienol. Alpha-tocopherol is the most active form in humans.

Dosing and daily allowance recommendations for vitamin E are often provided in alpha-tocopherol equivalents (ATEs) to account for the different biological activities of the various forms of vitamin E, or in international units (IU), which food and supplement labels may use. The conversion factor is 1mg of an ATE=1,5 IU.

Vitamin E supplements are available in natural or synthetic forms. The natural forms are usually labeled with the letter “d” (for example, d-gamma-tocopherol), whereas synthetic forms are labeled “dl” (for example, dl-alpha-tocopherol).

Foods that contain vitamin E include eggs, fortified cereals, fruit, green leafy vegetables (such as spinach), meat, nuts, nut oils, poultry, vegetable oils (corn, cottonseed, safflower, soybean, sunflower), argan oil, olive oil, wheat germ oil, and whole grains. Cooking and storage may destroy some of the vitamin E in foods.

Vitamin E has been proposed for the prevention or treatment of numerous health conditions, often based on its antioxidant properties. However, aside from the treatment of vitamin E deficiency (which is rare), there are a lack of clearly proven medicinal uses of vitamin E supplementation beyond the recommended daily allowance. There is ongoing research on its use in numerous diseases, particularly in cancer and heart disease.

Concerns have been raised about the safety of vitamin E supplementation, particularly in high doses. An increased risk of bleeding has been proposed, particularly in patients taking blood-thinning agents such as warfarin, heparin, or aspirin, and in patients with vitamin K deficiency. Evidence suggests that regular use of high-dose vitamin E supplements may increase the risk of death from all causes by a small amount, although human research is conflicting. Caution is warranted.

Scar prevention is another controversial use for vitamin E. While this use is commonly practiced, there is a lack of evidence for its efficacy. Because of a risk of contact dermatitis, some researchers have advised against the use of this therapy.

Dosing

NB! The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (over 18 years old)

Foods that contain vitamin E include eggs, fortified cereals, fruit, green leafy vegetables (such as spinach), meat, nuts, nut oils, poultry, vegetable oils (corn, cottonseed, safflower, soybean, sunflower), argan oil, olive oil, wheat germ oil, and whole grains. Cooking and storage may destroy some of the vitamin E in foods.

Most individuals in the United States are believed to obtain sufficient vitamin E from dietary sources, although individuals with very-low-fat diets or intestinal malabsorption disorders may require supplementation. Recommended dietary allowances (RDAs) for vitamin E are provided in alpha-tocopherol equivalents (ATEs) to account for the different biological activities of the various forms of vitamin E, as well as in international units (IU), which food and supplement labels often use. For conversion, one milligram of an ATE=1,5 IU. The RDA for men or women older than 14 years old is 15 milligrams (or 22,5 IU); for pregnant women of any age, it is 15 milligrams (or 22,5 IU), and for breastfeeding women of any age, it is 19 milligrams (or 28,5 IU).

For adults older than 18 years, the tolerable upper limit of dosing for supplementary alpha-tocopherol recommended by the U.S. Institute of Medicine is 1,000 milligrams daily (equivalent to 1,500 IU). This limit recommendation is not altered during pregnancy or breastfeeding.

Treatment of vitamin E deficiency should be under medical supervision, tailored to the underlying cause of the deficiency, and may include vitamin E taken by mouth or injected into the vein. If the cause is due to chronic malnutrition and there is no evidence of malabsorption, an oral dose that is 2-5 times greater than the RDA may be considered. If the cause is malabsorption that cannot be corrected, then vitamin E injected into the vein may be necessary. Dosing recommendations vary by the underlying cause.

No specific dosing of vitamin E has been established for other conditions, and there is recent evidence suggesting possible adverse health effects from long-term use of daily supplementation with 400 IU or greater daily. Although controversial, the use of long-term vitamin E supplementation should be approached cautiously until further evidence from prospective clinical trials is available. Various doses and durations have been evaluated in clinical trials, although many have not been proven as effective or safe. It is recommended that patients discuss the choice of dosing and duration with a licensed healthcare professional.

Children (under 18 years old)

Recommended dietary allowances (RDAs) for vitamin E are provided in alpha-tocopherol equivalents (ATEs) to account for the different biological activities of the various forms of vitamin E, as well as in international units (IU), because food and supplement labels often use this system. For conversion, one milligram of an ATE=1,5 IU. There is no RDA for infants, but there is a recommended adequate intake (AI) for healthy breastfeeding infants 0-6 months old of four milligrams daily (6 IU), and for infants 7-12 months old of five milligrams daily (7,5 IU). The RDA for children 1-3 years old is six milligrams daily (9 IU); for those 4-8 years old, it is seven milligrams daily (10,5 IU); for those 9-13 years old, it is 11 milligrams daily (16,5 IU); for those older than 14 years old, it is 15 milligrams daily (22,5 IU); for pregnant women of any age, it is 15 milligrams (22,5 IU); and for breastfeeding women of any age, it is 19 milligrams (28,5 IU).

An upper limit for infants up to 12 months of age has not been established. The tolerable daily upper limit of dosing for those 1-3 years old is 200 milligrams (300 IU); for those 4-8 years old, it is 300mg (450 IU); for those 9-13 years old, it is 600 milligrams (900 IU); and for those 14-18 years old, it is 800 milligrams (1200 IU).

Treatment of vitamin E deficiency should be under medical supervision, tailored to the underlying cause of the deficiency, and may include vitamin E taken by mouth or injected into the vein. If the cause is due to chronic malnutrition and there is no evidence of malabsorption, an oral dose that is 2-5 times greater than the RDA may be considered. If the cause is malabsorption that cannot be corrected, then vitamin E injected into the vein may be necessary. Vitamin E absorption may improve if given with meals, in small doses.

No specific dosing of vitamin E has been well established for other conditions.

Safety

NB! There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid with known allergy/hypersensitivity to products that contain vitamin E. Skin reactions such as contact dermatitis and eczema have been reported with topical vitamin E preparations, such as ointments or vitamin E-containing deodorants.

 Side Effects and Warnings

For short periods of time, vitamin E supplementation is generally considered safe at doses up to the recommended tolerable upper intake level (UL). However, vitamin E is possibly unsafe when used orally at doses exceeding the tolerable upper intake level. The recommended dietary allowance (RDA) obtained through food consumption is considered to be safe and beneficial.

The European Food Safety Authority (EFSA) has set the tolerable upper intake level (UL) for adults at 300 milligrams daily, regardless of pregnancy or lactation status. The UL for children ranges from 100 milligrams daily for ages 1-3 years to 260 milligrams daily for ages 15-17 years.

Evidence suggests that regular use of high-dose vitamin E may increase the risk of death from all causes by a small amount. These conclusions have been criticized by some experts. Nonetheless, this is the best available scientific evidence currently. Chronic use of vitamin E should be used cautiously, and high-dose vitamin E should be avoided. Acute overdose of vitamin E is very uncommon.

  • In rare cases, vitamin E supplementation has been associated with dizziness, fatigue, headache, weakness, blurred vision, abdominal pain, diarrhea, nausea, or flu-like symptoms (particularly when used in high doses). The risk of necrotizing enterocolitis may be increased with large doses of vitamin E.
  • Use cautiously in patients with cardiovascular conditions. Vitamin E may increase risk of all-cause mortality and incidence of heart failure with doses #8805;400 IU daily for over one year.
  • Vitamin E should be used cautiously for long periods of time (>10 years) due to a possible increased risk of hemorrhagic stroke.
  • Use cautiously in patients with skin conditions. Skin reactions, such as contact dermatitis and eczema, have been reported with topical vitamin E preparations, such as ointments or vitamin E-containing deodorants. Pruritus (itching) has been reported following oral supplementation of vitamin E.
  • Use cautiously in patients with kidney impairment. In rare cases, vitamin E supplementation has been associated with gonadal dysfunction and diminished kidney function.
  • Use cautiously in patients with Alzheimer’s disease or cognitive decline. In patients with Alzheimer’s disease or cognitive decline, vitamin E has been associated with an increase in falls and syncope (fainting).
  • Oral vitamin E should be used cautiously in patients with retinitis pigmentosa, as is does not appear to slow visual decline and may be associated with more rapid loss of visual acuity, although the validity of this finding has been questioned.
  • Use cautiously in patients who smoke. Vitamin E supplementation may transiently increase tuberculosis risk in males who smoke heavily and have high dietary vitamin C intake.
  • Vitamin E should be used cautiously in preterm infants, due to reports of an increased risk of sepsis. Premature infants should be under strict medical supervision. Decisions regarding vitamin supplementation should be made with the infant’s physician.
  • Although this has not been well studied in humans, an increased risk of bleeding when used with warfarin (Coumadin®) has been noted. However, other studies have not observed a greater incidence of bleeding. Bleeding has been observed in patients given high repeated doses of intravenous all-rac-alpha-tocopherol (synthetic vitamin E). Avoid in patients with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary. Reported adverse effects attributed to vitamin E supplementation included minor bleeding and epistaxis (nosebleed).
  • Avoid doses greater than the RDA in pregnant women, due to a possible increased risk of congenital heart defects in offspring.
  • Avoid with known allergy/hypersensitivity to products that contain vitamin E.

Pregnancy and Breastfeeding

Many prenatal vitamins contain small amounts of vitamin E. Natural forms of vitamin E may be preferable to synthetic forms. Vitamin E is in the U.S. Food and Drug Administration (FDA) Pregnancy Category A at doses advocated by the FDA. Doses above the RDA level are in FDA Pregnancy Category C.

Use beyond the recommended dietary allowance (RDA) level in otherwise healthy pregnant women is generally not recommended. There is otherwise insufficient evidence regarding the safety of higher doses of oral, topical, or injected vitamin E during pregnancy and breastfeeding, and therefore it is not recommended.

A combination of vitamins C and E may increase the risk of gestational hypertension (high blood pressure during pregnancy) and low-birthweight infants. Vitamin E use during pregnancy may increase the risk of congenital heart defects.

source: http://www.mayoclinic.com

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