The Centers for Disease Control and Prevention report that over half of Americans use dietary supplements. One of those supplements is vitamin E, first discovered in 1922 and given the scientific name tocopherol, meaning "to bring forth." This proved to be an appropriate name, since vitamin E is essential for promoting good health, but too much of the vitamin can cause health problems.
Identification
Vitamin E has eight different chemical forms, although only alpha-tocopherol meets your body's nutritional needs. Vitamin E is a fat-soluble vitamin, meaning that it's stored in your liver and fatty tissues and eliminated much more slowly than water-soluble vitamins such as vitamin C. Vitamin E is found in foods such as asparagus, mangoes, nuts and seeds, olives, spinach, vegetable oils, wheat germ and whole-wheat breads. The recommended daily allowance for adults for vitamin E is 22.4 international units, or IU, which is the equivalent of 15 mg.
Misconceptions
In January 2005, a study from Johns Hopkins University made headlines by reporting in the "Annals of Internal Medicine" that daily doses of vitamin E above 400 IU could increase the risk of death. This report made many people afraid to take supplemental vitamin E. However, most of the patients in all of the trials analyzed by Johns Hopkins were over 60 and had pre-existing health problems, such as heart trouble or kidney disease. Even the Hopkins researchers noted that their findings might not be applicable to people who were younger and healthier. Also, others have pointed out that vitamin E was often used in combination with pharmaceutical drugs in the trials, which could affect the data.
Benefits
Vitamin E is an antioxidant and may help protect the cells in your body from harmful free radicals that cause cancer, diabetes and cardiovascular disease. Vitamin E is also important for a healthy immune system and certain metabolic processes. Vitamin E also has cardiovascular benefits; arachidonic acid is a substance that in excess can cause various health problems, and vitamin E helps boost enzymes that keep arachidonic acid levels low. This in turn dilates the lining of your blood vessels to help prevent platelet clumping that can lead to clots.
Toxicity
Overdoses of vitamin E aren't very common. The National Institutes of Health Office of Dietary Supplements reports that high doses of vitamin E at 400 IU taken in combination with aspirin may increase your risk for serious bleeding problems and hemorrhagic strokes. In rare cases, vitamin E supplementation has been linked to gonad dysfunction in men and diminished kidney function in both men and women. It's also unknown if vitamin E supplements are safe if you are pregnant or have retinitis pigmentosa, since evidence is conflicting. The Institute of Medicine of the National Academies established upper tolerable limits for vitamin E of 1,500 IU daily for adults age 19 and over for the natural form of vitamin E or 1,100 IU daily for the synthetic form.
Other Side Effects
Some people using topical products such as ointments or deodorants that contain vitamin E have experienced contact dermatitis and eczema. Others taking oral dietary vitamin E supplements have had gastrointestinal problems, flu-like symptoms, dizziness, fatigue, headache, weakness or blurred vision. However, these symptoms tend to occur at higher doses.
References
- Office of Dietary Supplements: Vitamin E
- "Annals of Internal Medicine"; Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase All-Cause Mortality; Edgar R. Miller III, M.D., et al.: January 2005
- MayoClinic.com; Vitamin E Safety; April 2011
- Drugs.com; Vitamin E; 2009
- Centers for Disease Control and Prevention; Dietary Supplement Use Among U.S. Adults Has Increased Since NHANES III (1988--1994)
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