Vitamin E (sometimes called alpha-tocopherol) is in many foods, including nuts, oils, and vegetables. People in western countries usually consume small but adequate amounts of this vitamin in their diets. People also can buy multivitamins and supplements that contain vitamin E. Each multivitamin often contains about 30 international units (IU) of vitamin E. Many experts recommend this daily amount for adults. Supplements often contain much larger amounts, such as 200, 400, or 1000 IU. Some research suggests that taking vitamin E supplements may boost immune systems and prevent heart disease and some types of cancer. Other research suggests that taking large amounts of vitamin E as supplements may increase risks for bleeding problems and death. Because of these risks, some experts set 1500 IU daily as the upper tolerable intake level for vitamin E. To make good decisions about taking or not taking vitamin E, people need information about its safety.