Chemically unstable molecules known as free radicals are produced simultaneously when the body burns oxygen to produce energy. Free radicals cause damage to brain cells by taking electrons from the body's healthy molecules to balance themselves. The body can usually handle a small amount of free radicals, but when the number of free radicals becomes excessive, then the danger sets in. A large amount of free radicals leads to even more free radicals, and this excessive free radical formation damages cells and tissues. When this oxidative damage affects your brain the effect sneaks up slowly, and ever so quietly steals away a person's memory and personality, eventually eroding his ability to even take care of himself.

Numerous studies have been conducted to test the role antioxidants have in the development of heart disease, cancer, Parkinson's disease, and other diseases linked to excessive oxidation. In one study, Parkinson's disease patients were given doses of vitamin A and C for seven years. Eventually all the patients needed some drug treatment, but the antioxidant nutrients slowed the progression of the disease considerably.[A pilot trial of high-dose alpha-tocopherol and ascorbate in early Parkinson's disease. Annals of Neurology 1992; 32: S128-132]

Because of these results, scientists decided to try antioxidant nutrients on Alzheimer's disease patients, but there has been only one trial study published so far. In this study, patients with moderately severe Alzheimer's disease were given either the monoamine oxidize inhibitor selegiline, vitamin E, a combination of selegiline and vitamin E, or a placebo. Of the four groups, those who were given vitamin E clearly showed the most positive results. Compared to the 39 percent placebo patients who had to be institutionalized, the vitamin E group only had 26 percent.