Vitamin E

What is vitamin E?

Vitamin E is a group of fat-soluble compounds, of which alpha-tocopherol is the form the body uses most. It acts as an antioxidant in cell membranes and plays roles in immune function and cell signaling. Good food sources include nuts, seeds, vegetable oils, green leafy vegetables and fortified cereals (ODS vitamin E fact sheet).

The NIH Office of Dietary Supplements (ODS) lists Recommended Dietary Allowances of 15 to 19 mg for adults and a tolerable upper intake level of 1,000 mg per day for supplemental vitamin E. ODS notes that natural vitamin E (labeled d- or RRR-alpha-tocopherol) is about twice as active as the synthetic form (dl- or all-rac) (ODS).

What the research says

Vitamin E’s antioxidant activity once made it a popular candidate for preventing heart disease and cancer. Clinical trials did not bear this out. According to ODS, vitamin E supplements have not been shown to prevent cardiovascular disease, and the available evidence does not support using them to prevent cancer (ODS).

For men, the most important study is the Selenium and Vitamin E Cancer Prevention Trial (SELECT). It randomized more than 35,000 relatively healthy men to vitamin E (400 IU per day of synthetic alpha-tocopheryl acetate), selenium, both, or placebo. With extended follow-up, men taking vitamin E alone had a statistically significant increase in prostate cancer risk compared with placebo (Klein et al., 2011). ODS summarizes this as evidence that regularly taking large doses of vitamin E may even increase the risk of prostate cancer (ODS). Clinical trials have also linked high-dose vitamin E to a higher risk of hemorrhagic stroke.

There is no clinical evidence that vitamin E improves prostate size, urinary flow or prostate symptoms.

How it’s used in supplements

Vitamin E appears in multivitamins, antioxidant formulas and men’s products. Small amounts near the RDA (for example 13 mg, about 87% of the daily value) are very different from the 400 IU doses used in SELECT and are unlikely to pose the same risk, but they also offer no proven prostate benefit.

If you take several supplements, add up your vitamin E and avoid high-dose products unless a doctor recommends them. ODS notes that vitamin E supplements can interact with anticoagulant and antiplatelet drugs (raising bleeding risk), simvastatin with niacin, and some chemotherapy and radiotherapy treatments (ODS).

The bottom line: get your vitamin E from foods such as nuts, seeds and vegetable oils, and be wary of men’s products that provide high doses. The SELECT results are a clear example of an antioxidant that looked promising in theory but caused harm in a large trial of healthy men. Small amounts near the RDA in a multivitamin or men’s formula are unlikely to cause problems, but there is no reason to seek out extra vitamin E for prostate health.