Vitamin E is a fat-soluble vitamin found in green leafy vegetables, whole grains, nuts and seeds, wheat germ, eggs, and in oils derived from soybeans, almonds, safflower, and sunflower. It is also an antioxidant and is said to confer protection against Alzheimer’s, Parkinson’s, cardiovascular disease, arthritis, and cancer.
Although observational data suggest a correlation between high intake of foods rich in vitamin E(Drug information on vitamin e) and lowered risk of cancer, randomized trials using vitamin E supplements failed to validate those findings; some studies suggest that vitamin E supplementation can actually increase all-cause mortality.
In addition, because of its antioxidant property, vitamin E can interfere with the actions of certain chemotherapeutic agents.
Further studies are needed to resolve the uncertainty over vitamin E supplementation in disease prevention. Many studies now show that dietary supplements are not equivalent to foods in efforts to obtain sufficient vitamin levels.
—Barrie Cassileth, PhD
ALSO KNOWN AS: Tocopherol, alpha-tocopherol, dl-tocopherol, tocotrienol.
SUMMARY: Vitamin E is a fat-soluble vitamin found in green leafy vegetables, whole grains, nuts and seeds, wheat germ, eggs, and in oils derived from soybeans, almonds, safflower, and sunflower. It acts as an antioxidant and is purported to help prevent Alzheimer’s disease, Parkinson’s disease, cardiovascular disease, arthritis, and cancer. The supplemental form of vitamin E is available in the form of topical oils and as tablets and capsules.
Vitamin E supplementation was shown to improve immune response in the elderly, and to slow the progression of Alzheimer’s disease, but was ineffective in arresting the development or progression of early Parkinson’s disease and macular degeneration.
Other studies failed to support benefits of vitamin E in reducing the incidence of acute respiratory tract infections and in lowering the risk of cardiovascular disease; vitamin E actually may increase the risk of stroke.
The role of vitamin E in cancer prevention is ambiguous. Data from observational studies suggest a positive association between consumption of foods high in vitamin E and reduced risk of cancer. Vitamin E supplementation was also effective against hot flashes in breast cancer survivors, and in reducing neurotoxicity in patients treated with cisplatin(Drug information on cisplatin).
However, supplementation with vitamins E, C, and beta carotene did not prevent cancer incidence in randomized clinical trials, nor did it affect cancer mortality.
The large prevention study SELECT (Selenium and Vitamin E Cancer Prevention Trial), based on previous data indicating that selenium(Drug information on selenium) and vitamin E reduced the incidence of prostate cancer, also failed to support their protective effects. The trial was suspended in January 2009, when initial data analysis showed no reduction in the risk of prostate cancer with selenium alone or with vitamin E.
Vitamin E supplementation may also increase the risk of lung cancer and overall mortality.
ADVERSE REACTIONS: Daily supplementation over 400 IU may increase all-cause mortality.
Vitamin E supplementation may increase the risk of hemorrhagic stroke.
Warfarin: It has been reported that vitamin E at doses greater than 400 IU per day may increase the effects of warfarin(Drug information on warfarin), but data are inconsistent.[14,15]