Vitamin E supplementation in Alzheimer's disease, Parkinson's disease, tardive dyskinesia, and cataract: Part 2.
OBJECTIVE
To review clinical trials evaluating the safety and efficacy of vitamin E supplementation in Alzheimer's disease, Parkinson's disease, tardive dyskinesia, and cataract.


METHODS
Using the MeSH terms alpha-tocopherol, tocopherols, vitamin E, Parkinson disease, tardive dyskinesia, Alzheimer disease, cataract, and clinical trials, a literature review was conducted to identify peer-reviewed articles in MEDLINE (1966-July 2005).


METHODS
Published materials including original research, review articles, and meta-analyses were reviewed. Only English-language articles and trials that included vitamin E alone or in combination with other vitamins or minerals were reviewed. Emphasis was placed on prospective, randomized, double-blind, placebo-controlled clinical trials.


RESULTS
The clinical studies demonstrated contradicting results regarding the benefits of vitamin E in Parkinson's disease, tardive dyskinesia, and cataract. The study reviewed for Alzheimer's disease seemed to show benefit when vitamin E was used; however, the statistical methods employed are questionable. There is enough evidence from large, well-designed studies to discourage the use of vitamin E in Parkinson's disease, cataract, and Alzheimer's disease. We recommend that vitamin E be considered a treatment option in patients with tardive dyskinesia only if they are newly diagnosed.


CONCLUSIONS
We encourage patients to supplement with vitamin E-rich foods. The use of a daily multivitamin, which usually contains 30 IU of alpha-tocopherol, may be beneficial; however, we discourage individual vitamin E supplements that usually contain 400 IU of alpha-tocopherol.
Pham
David Q
DQ
Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, NY 11201, USA. david.pham@liu.edu
Plakogiannis
Roda
R
D000544:Alzheimer Disease / Q000517:prevention & control*; D000975:Antioxidants / Q000009:adverse effects / Q000627:therapeutic use*; D002386:Cataract / Q000517:prevention & control*; D002986:Clinical Trials as Topic; D004409:Dyskinesia, Drug-Induced / Q000517:prevention & control*; D006801:Humans; D010300:Parkinson Disease / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D014810:Vitamin E / Q000009:adverse effects / Q000627:therapeutic use*
D000975:Antioxidants; D014810:Vitamin E