What is the potential importance of taking vitamin E?

A nationwide study recently reported that 27% of the U.S. population had low blood levels of vitamin E. Supplementing with at least 100 IU per day of vitamin E is associated with lowered risk of heart disease, and a double-blind study found that 400 to 800 IU of vitamin E per day reduced the risk of nonfatal heart attacks, but not fatal ones. However, another double-blind trial found no benefit from 400 IU per day of vitamin E supplementation on the risk of non-fatal heart attacks, while another study found that 50 IU per day had no effect on heart attack risk. A more recent study found that taking large amounts of vitamin E (400 IU per day or more) may result in a small increase in all-cause mortality, while another study found that 400 IU per day increased the risk of heart failure. Because of these studies, some doctors are advising people not to take large amounts of vitamin E. On the other hand, circumstantial evidence suggests that “mixed tocopherols,” as opposed to the more widely used alpha-tocopherol, may be safer and more beneficial with respect to heart-disease prevention.

A reduced risk of prostate cancer in smokers was reported in a double-blind trial with 50 IU per day of vitamin E. However, similar studies have not found vitamin E supplements to protect against other cancers.