BROOKLYN, N.Y. & COLUMBUS, Ga.--Treatment of Alzheimer's disease (AD) with substantial doses of vitamin E may not be safe or effective, according to two separate meta-analyses published in the Annals of Pharmacotherapy (39, 12: 2065-71, 2005) (39, 12: 2073-79, 2005).
Using key word searchers, two different groups of researchers combed databases including MEDLINE (between 1966 and 2005), International Pharmaceutical Abstracts (from 1970 and March 2005), Current Contents (from 1996 and March 2005), Cochrane Database of Systematic Reviews (from 1994 and March 2005) and Ebsco's Academic Search Elite (from 1975 and March 2005), for randomized, controlled trials involving vitamin E and AD. Based upon the results of their search, the first group of researchers, from Kings County Hospital Center and Bellevue Hospital Center, concluded there is enough evidence from large, well-designed studies to discourage the use of vitamin E in AD, and encouraged patients to limit vitamin E supplementation to 30 IU/d.
The second group of researchers, from Auburn University and the University of Florida, cited a specific prospective observational study in which the combined use of 400 IU/d vitamin E and 500 mg/d vitamin C was associated with the reduction of AD prevalence and incidence; however, they also found another prospective observational study in which supplementation with presumably similar amounts of vitamins E and C over four years appeared to have no impact on the incidence of AD. They further uncovered recent meta-analyses and a mega-trial in which doses of more than 400 IU/d of vitamin E for more than one year and over 6.9 years in patients with preexisting vascular disease or diabetes mellitus were associated with increased all-cause mortality and incidence of heart failure, respectively, providing additional evidence that vitamin E supplementation may not be advisable among elderly AD patients. The researchers concluded vitamin E supplements should not be recommended for primary or secondary prevention of AD, due to a lack of prospective, randomized, controlled clinical trials documenting benefits that outweigh recently documented morbidity and mortality risks.
