Clinical Fact Sheet-Vitamin E and Beta-Carotene (alpha-tocopherol)
Clinical Fact Sheet-Vitamin E and Beta-Carotene (alpha-tocopherol)
January 2001; Volume 4; S1-S2
Although vitamin e is found only in small amounts in the diet, deficiency is rare. Likewise, supplementation to prevent deficiency in adults is not warranted. Vitamin E is used most widely as a dietary supplement for the prevention of cardiovascular disease.
Dietary Reference Intakes (DRI)
4 mg/d for children 0-6 mo 7 mg/d for children 4-8 y
6 mg/d for children 7-12 mo 11 mg/d for children 9-13 y
6 mg/d for children 1-3 y 15 mg/d for men and women 14 y and older
Active Constituents
Vitamin E is a fat-soluble vitamin that consists of a family of eight compounds: four tocopherols (alpha, beta, gamma, and delta) and four additional tocotrienol derivatives. Natural vitamin E (d-alpha tocopherol) is the most bioavailable; however, claims of its superiority over synthetic vitamin E (dl-alpha tocopherol) remain controversial.
Food Sources
• Vegetable oils, wheat germ oil, seeds, nuts, soybeans, leafy greens, brussels sprouts, whole wheat products, whole grain breads and cereals, avocados, spinach, and asparagus.
Mechanism of Action
• Functions as a free radical scavenger and prevents oxidative damage to lipid membranes and LDL.
• Enhances T lymphocyte function.
Clinical Uses
• To reduce the risk of cardiovascular disease by decreasing platelet stickiness, protecting blood vessels against developing atherosclerotic lesions, and protecting LDL-cholesterol against oxidation.
• To reduce the risk of certain cancers, including lung, oral, colon, rectal, cervical, prostate, pancreatic, and liver.
• To reduce the risk and slow the progression of Alzheimer's disease and other dementias.
• To reduce the symptoms of premenstrual syndrome.
• To improve sperm function and fertility rates.
• To normalize retinal blood flow and to improve renal function in type 1 diabetics.
• To enhance immune system function and increase resistance to infection.
• To reduce the amount of exercise-induced free radical damage and the incidence of exercise-induced muscle injury.
• To reduce the risk of macular degeneration and cataracts.
• To reduce the risk of pre-eclampsia in high-risk women.
Adverse Effects/Toxicity
• The primary route of excretion of ingested vitamin E is fecal elimination.
• Vitamin E can potentiate blood clotting time; large doses are not recommended for patients taking anti-coagulant drugs (warfarin).
• Isolated cases of vitamin E toxicity have been reported in patients taking more than 1,000 IU/d. Symptoms include headache, fatigue, nausea, double vision, muscular weakness, and GI distress.
Interactions/Nutrient Depletion
• Vitamin E is destroyed by heat and oxidation during cooking or food processing.
• Absorption can be decreased by cholestyramine resin, colestipol, ethanol, isoniazid, lopid, and mineral oil.
• Low levels of selenium and high intake of polyunsaturated fatty acids contribute to vitamin E depletion.
• Co-administration with iron may delay absorption.
• Absorption depends on the presence of bile and is reduced in those people taking orlistat or with fat malabsorption syndromes (pancreatic and liver disease).
January 2001; Volume 4; S1-S2
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