The USPSTF found inadequate evidence to assess the balance of benefits and harms of supplements of single or paired vitamins, multivitamins, or minerals to prevent CVD or cancer. Only 2 vitamin supplements, beta-carotene and vitamin E, have sufficient evidence to weigh the balance of benefits and harms. Beta-carotene supplements have been associated with an increased risk for cancer in smokers, so the harms outweigh the benefits. Large, high-quality studies show that vitamin E supplements have no effect on CVD, cancer, or death rates. The USPSTF concludes that there is no benefit of vitamin E supplements to prevent these conditions.