What you need to know about Vitamin E
Vitamin E is a fat-soluble vitamin with several forms, but alpha-tocopherol is the only one used by the human body. Its main role is to act as an antioxidant, scavenging loose electrons—so-called “free radicals”—that can damage cells. It also enhances immune function and prevents clots from forming in heart arteries. Antioxidant vitamins, including vitamin E, came to public attention in the 1980s when scientists began to understand that free radical damage was involved in the early stages of artery-clogging atherosclerosis, and might also contribute to cancer, vision loss, and a host of other chronic conditions. Vitamin E has the ability to protect cells from free radical damage as well as stop the production of free radical cells entirely. However, conflicting study results have dimmed some of the promise of using high dose vitamin E to prevent chronic diseases.
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The Recommended Dietary Allowance (RDA) for vitamin E for males and females ages 14 years and older is 15 mg daily (or 22 international units, IU), including women who are pregnant. Lactating women need slightly more at 19 mg (28 IU) daily.
- Wheat germ oil
- Sunflower, safflower, and soybean oil
- Sunflower seeds
- Peanuts, peanut butter
- Beet greens, collard greens, spinach
- Red bell pepper
Signs of Deficiency
Because vitamin E is found in a variety of foods and supplements, a deficiency in the U.S. is rare. People who have digestive disorders or do not absorb fat properly (e.g., pancreatitis, cystic fibrosis, celiac disease) can develop a vitamin E deficiency. The following are common signs of a deficiency:
- Retinopathy (damage to the retina of the eyes that can impair vision)
- Peripheral neuropathy (damage to the peripheral nerves, usually in the hands or feet, causing weakness or pain)
- Ataxia (loss of control of body movements)
- Decreased immune function
There is no evidence of toxic effects from vitamin E found naturally in foods. Most adults who obtain more than the RDA of 22 IU daily are using multivitamins or separate vitamin E supplements that contain anywhere from 400-1000 IU daily. There have not been reports of harmful side effects of supplement use in healthy people. However, there is a risk of excess bleeding, particularly with doses greater than 1000 mg daily or if an individual is also using a blood thinning medication such as warfarin. For this reason, an upper limit for vitamin E has been set for adults 19 years and older of 1000 mg daily (1465 IU) of any form of tocopherol supplement.
Did You Know?
Due to occasional reports of negative health effects of vitamin E supplements, scientists have debated whether these supplements could be harmful and even increase the risk of death.
Researchers have tried to answer this question by combining the results of multiple studies. In one such analysis, the authors gathered and re-analyzed data from 19 clinical trials of vitamin E, including the GISSI and HOPE studies ; they found a higher rate of death in trials where patients took more than 400 IU of supplements a day. While this meta-analysis drew headlines when it was released, there are limitations to the conclusions that can be drawn from it. Some of the findings were based on very small studies. In some of these trials, vitamin E was combined with high doses of beta-carotene, which itself has been related to excess mortality.
Furthermore, many of the high-dose vitamin E trials included in the analysis included people who had advanced heart disease or Alzheimer’s disease. Other meta-analyses have come to different conclusions. So it is not clear that these findings would apply to healthy people. The Physicians’ Health Study II, for example, did not find any difference in death rates between the study participants who took vitamin E and those who took a placebo.