Vitamin E is an antioxidant responsible for proper functioning of the immune system and for maintaining healthy eyes and skin. It is actually a group of fatsoluble compounds that include alpha-, beta-, gamma-, and delta-tocopherol, and alpha-, beta-, gamma-, and delta-tocotrienol. Only one of them—alpha-tocopherol—is recognized to meet human requirements for vitamin E. While vitamin E has been reported to have numerous health benefits, studies also show that supplements can slightly increase the incidence of cardiovascular death, and significantly increase the risk of prostate cancer in men.
Vitamin E is a fat-soluble vitamin. Other fat-soluble vitamins include vitamins A, D, and K. These are different from water-soluble vitamins, such as vitamin C and the B-complex vitamins. Water-soluble vitamins need to be replaced regularly in the body, but fat-soluble vitamins are eliminated from the body much more slowly. They are stored in the liver and fatty tissues. Because vitamin E is a fat-soluble vitamin, it requires the presence of fat for proper absorption. Dietary intake of the recommended daily allowance (RDA) of vitamin E promotes optimum health. Foods that are rich in vitamin E include nuts, cereals, beans, eggs, coldpressed oils, and assorted fruits and vegetables.
Vitamin E is absorbed by the gastrointestinal system and stored in tissues and organs throughout the body. Certain health conditions may cause vitamin E depletion, including liver disease, celiac disease, and cystic fibrosis. Patients with end-stage renal disease (kidney failure) who are undergoing chronic dialysis treatment may be at risk for vitamin E deficiency. These patients frequently receive intravenous infusions of iron supplement, which can act against vitamin E. Vitamin E deficiency can cause fatigue, concentration problems, weakening of the immune system, anemia, and low thyroid levels. It may also cause vision problems and irritability. Low serum (or blood) levels of vitamin E have also been linked to major depression.
Vitamin E is necessary for optimal immune-system functioning, healthy eyes, and cell protection throughout the body. It has antioxidant, anti-inflammatory, and immunity-boosting properties, and has also been linked to the prevention or treatment of a number of diseases.
Cancer prevention and treatment
Vitamin E is a known antioxidant and has been associated with a reduced risk of various types of cancer. Most research studies, however, indicate that vitamin E supplements do not reduce the risk of cancer. In addition, one major study (called the Selenium and Vitamin E Cancer Prevention Trial, or SELECT) found that a vitamin E regimen led to an increased risk of prostate cancer. That study began in 2008 and was expected to run until 2013, but the vitamin E dosing ended early when a slight rise in cancer incidence was noted. Researchers continued to follow the participants, and in 2011, they reported in the Journal of the American Medical Association (JAMA) that ‘‘dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men.’’
Other studies have shown that vitamin E is ineffective against the growth of existing cancer as well as the incidence of cancer recurrence. For the latter, researchers investigated the effects of vitamin E on patients who had survived head and neck cancer, and found no evidence that vitamin E was beneficial in protecting the patients from a second, new cancer.
Immune system protection
Various studies have shown that vitamin E supplementation, particularly in elderly patients, boosts immune-system function. Older patients have demonstrated improved immune response, increased resistance to infections, and higher antibody production. Vitamin E has also been suggested to slow disease progression in HIV-positive patients.
Although vitamin E supplementation has been suggested for its potential benefits in reducing the risk of macular degeneration, a 2012 study in the journal Ophthalmology found no benefit. For the study, researchers followed 39,876 apparently healthy female health professionals aged 45 years or older for 10 years. About half received alternate-day supplements of 600 IU vitamin E, and the other half received a placebo. Over that time, 117 of the women in the vitamin E group developed macular degeneration compared to 128 in the placebo group. Based on the very similar incidence of the disease, the researchers concluded that vitamin supplementation provided no protective benefit.
Alzheimer’s disease treatment
Research studies have provided conflicting reports of vitamin E’s effectiveness in treating individuals with Alzheimer’s disease (AD). Some studies have shown that patients who took daily supplements of vitamin E maintained normal functioning longer than patients who took a placebo, and that vitamin E actually lowered the risk of developing AD. Other studies have not shown positive results. For example, researchers found ‘‘no convincing evidence’’ that vitamin E was beneficial in treating mild cognitive impairment or Alzheimer’s dementia. They based their conclusion on their review of the scientific literature, and reported their findings in a 2012 issue of Cochrane Database of Systemic Reviews.
Liver disease treatment
Some research indicates that vitamin E may help protect the liver against disease, especially the type known as non-alcoholic fatty liver disease or nonalcoholic steatohepatitis. Researchers tested whether vitamin E at a dose of 800 IU daily had an effect on adult patients who had this fairly common disease, and reported their findings in the New England Journal of Medicine. Compared to those patients who received a placebo, the patients who took the vitamin E supplement experienced a significantly higher improvement.
Vitamin E acts as both an anti-inflammatory and analgesic (or pain reliever). Studies have indicated it may be useful for treatment of arthritis pain in some individuals.
Tardive dyskinesia treatment
Individuals who take neuroleptic drugs for schizophrenia or other disorders may suffer from a side effect known as tardive dyskinesia, in which they experience involuntary muscle contractions or twitches. Vitamin E supplementation may lessen or eliminate this side effect in some individuals.
Vitamin E has been found to be beneficial in treating patients with porphyria, a group of disorders characterized by abnormalities in the metabolism of blood pigments, by lowering the level of excretion of these blood pigments in the urine.
Heart disease prevention
A number of epidemiological studies have indicated that Vitamin E may prevent heart disease by lowering total blood cholesterol levels and preventing oxidation of LDL cholesterol. Additional studies, however, indicated that vitamin E showed no benefit for lowering mortality, significantly reducing the risk of cardiovascular death or stroke, or preventing cardiovascular disease. Some researchers also recommended against the use of vitamin E, because over-the-counter supplements often include beta-carotene, which in some studies slightly increased cardiovascular death. Further large, controlled, and long-term clinical studies are necessary to resolve the conflicting reports of vitamin E’s effectiveness in preventing heart disease.
Vitamin E is thought to increase an individual’s tolerance to ultraviolet rays when taken as a supplement in conjunction with vitamin C. Vitamin E has also been touted as a treatment to promote faster healing of flesh wounds. While its anti-inflammatory and analgesic properties may have some benefits in reducing swelling and relieving discomfort in a wound, some dermatologists dispute the claims of faster healing, and large controlled studies to support this claim are lacking.
Studies suggest that menopausal women and breast-cancer survivors who suffer from hot flashes experience a decrease in hot flashes after taking vitamin E supplements. Some women also use intravaginally placed vitamin E gel capsules to help treat the vaginal dryness associated with menopause.
In 2011, researchers reported in Nature Communications that vitamin E is important to the repair of tears in cells’ plasma membranes. One role of these membranes is to control what enters the cells, and this includes highly reactive and damaging molecules called free radicals.
Vitamin E has been shown to improve sperm function in animal studies, and a 2012 study also found that when combined with selenium (a trace element found in many foods), it is effective in improving semen quality and motility among infertile men. The men in the study received a combination daily supplement of 200 micrograms of selenium and 400 IU of vitamin E for at least 100 days. More than half experienced improved sperm motility and or sperm morphology, and nearly 11 percent experienced a pregnancy while taking the regimen.
The U.S. recommended dietary allowance (RDA) of the alpha-tocopherol form of vitamin E is as follows:
- children aged 1–3 years: 6 mg or 9 international units (IU)
- children aged 4–8 years: 7 mg or 10.4 IU
- children aged 9–13 years: 11 mg or 16.4 IU
- individuals 14 years old and older: 15 mg or 22.4 IU
- lactating women: 19 mg or 28.4 IU
Adequate intake of vitamin E for infants is 4 mg or 6 IU up to 6 months and 5 mg or 7.5 IU for ages 7–12 months. Many nuts, vegetable-based oils, fruits, and vegetables contain vitamin E. Foods rich in vitamin E include wheat germ oil (26.2 mg/tbsp), wheat germ cereal (19.5 mg/cup), peanuts (6.32 mg/half cup), soy beans (3.19 mg/cup), corn oil (2.87/tbsp), avocado (2.69 mg), and olive oil (1.68 mg/tbsp). Grapes, peaches, broccoli, brussels sprouts, eggs, tomatoes, and blackberries are also good sources of vitamin E. For individuals considered at risk for vitamin E deficiency, or those with an inadequate dietary intake, vitamin E supplements are available in a variety of different forms, including pills, capsules, powders, and liquids for oral ingestion. For topical use, vitamin
E is available in ointments, creams, lotions, and oils. Vitamin E is also available commercially as one ingredient of a multivitamin formula. The recommended daily dosage of vitamin E varies by individual need and by the amount of polyunsaturated fats an individual consumes. The more polyunsaturated fats in the diet, the higher the recommended dose of vitamin E, because vitamin E helps to prevent the oxidizing effects of these fats. Because vitamin E is fat-soluble, supplements should always be taken with food. Supplements are also available in either natural or synthetic formulations. Natural forms are extracted
from wheat germ oil and other vitamin E food sources, and synthetic forms are extracted from petroleum oils. Natural formulas can be identified by a ‘‘d’’ prefix on the name of the vitamin (e.g., d-alpha-tocopherol)
Overdoses of vitamin E (more than 536 mg) can cause nausea, diarrhea, headache, abdominal pain, bleeding, high blood pressure, fatigue, and weakened immune system function.
Patients with rheumatic heart disease, irondeficiency anemia, hypertension, diabetes, or thyroid dysfunction should consult their healthcare providers before starting vitamin E supplementation, as vitamin E may have a negative impact on these conditions.
Vitamin E is well tolerated, and side effects are rare. However, in some individuals who are vitamin K deficient, vitamin E may increase the risk for hemorrhage or bleeding. In some cases, side effects may be decreased or eliminated by adjusting the dosage of vitamin E and vitamin K. High doses of vitamin E supplements may increase the risk for bleeding, including potentially dangerous bleeding in the brain. In addition, high levels of vitamin may increase the risk of birth defects, so women who are pregnant or who may become pregnant should consult their physicians before taking vitamin E supplements.
Some researchers also recommend against the use of vitamin E, because over-the-counter supplements often include beta-carotene, which in some studies showed a slight increase in cardiovascular death.
Another study noted an increase in the incidence of prostate cancer in men who took high doses of vitamin E.
Vitamin E ointments, oils, or creams may trigger an allergic reaction known as contact dermatitis.
Individuals who are considering using topical vitamin E preparations for the first time, or who are switching the type of vitamin E product they use, should perform a skin patch test to check for skin sensitivity to the substance. A dime-sized drop of the product should be applied to a small patch of skin inside the elbow or wrist. The skin patch should be monitored for 24 hours to ensure that no excessive redness, irritation, or rash occurs. If a reaction does occur, it may be in response to other ingredients in the topical preparation, and the test can be repeated with a different vitamin E formulation. Individuals who experience a severe reaction to a skin patch test of vitamin E are advised not to use the product topically. A dermatologist or other healthcare professional may be able to recommend a suitable alternative.
Individuals who take anticoagulant (blood-thinning) or anticonvulsant medications should consult their healthcare providers before starting vitamin E supplementation. Vitamin E can alter the efficacy of these drugs.
It is important for persons taking supplemental vitamin E to tell their surgeon if they are scheduled for an operation. Vitamin E may interact with some of the medications given prior to or during surgery; it has also been shown to increase bleeding time if the patient is taking such other herbal preparations as feverfew or gingko biloba.
Non-heme, inorganic iron supplements destroy vitamin E, so individuals taking iron supplements should space out their doses (e.g., iron in the morning and vitamin E in the evening).
Large doses of vitamin A can decrease the absorption of vitamin E, so dosage adjustments may be necessary in individuals supplementing with both vitamins.
Alcohol and mineral oil can also reduce vitamin E absorption, and these substances should be avoided if possible in vitamin E–deficient individuals.