Vitamin E has been shown to be good for Alzheimer disease. However, the following study showed that it increased all-cause mortality.
“A meta-analysis has found an increase in all-cause mortality associated with the use of vitamin E at a dosage of >400 mg/day. In addition, β-Carotene has been found in clinical trials with smokers to be related to increased rates of lung cancer and overall mortality. Furthermore, in 2003 the U.S. Preventive Services Task Force specifically recommended against the use of β-carotene for chemoprevention (USPSTF D recommendation). The evidence for vitamins A and C, and for multivitamins with folic acid, is insufficient to recommend for or against their use for chemoprevention of cancer or cardiovascular disease (USPSTF I recommendation).
References:
- Miller ER III, Pastor-Barriuso R, Dalal D, et al: Meta-analysis: High-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005;142(1):37-46.
http://www.annals.org/cgi/content/full/142/1/37 - Final Recommendation Statement: Vitamin supplementation to prevent cancer and CVD: Counseling. US Preventive Services Task Force, 2014.
http://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/vitamin-supplementation-to-prevent-cancer-and-cvd-counseling”