Long-term use of vitamin E supplements may decrease the risk of amyotrophic lateral sclerosis (ALS), according to a study published online in the Annals of Neurology on November 4, 2004. ALS, also known as Lou Gehrig’s disease, is a neurodegenerative disease characterized by the death of motor neurons, which are nerves that control the movement of all voluntary muscles. This loss of motor neurons results in progressive muscle weakness, muscle atrophy, spastic paralysis and death within 1-5 years. More than 5,000 people in the U.S. are diagnosed with ALS each year, and currently there is no cure.
Although the cause of motor neuron death in ALS is unknown, oxidative stress may play a role. Researchers from the Harvard School of Public Health and the American Cancer Society followed more than 900,000 men and women for sixteen years to determine whether antioxidant supplement use was associated with a decreased risk of developing ALS. They found that people who reported taking vitamin E supplements regularly for more than 10 years when the study began were 60% less likely to die from ALS than those who did not take vitamin E supplements. Participants in the study did not provide any information about the dose of the vitamin E supplements they took, but a typical vitamin E supplement contains 400 IU of synthetic d,l-alpha-tocopherol, which is equivalent to 200 IU of natural d-alpha-tocopherol. In contrast, vitamin C and multivitamin supplement use were not associated with ALS risk. Although these results need confirmation by future studies, they suggest that vitamin E may play a role in the prevention of ALS.
Maret Traber, the Linus Pauling Institute’s vitamin E expert, notes that long-term use of vitamin E supplements can double vitamin E concentrations in the brain. Her work indicates that absorption of this fat-soluble antioxidant vitamin can be maximized by taking vitamin E supplements with dinner. More information on vitamin E can be found in the Linus Pauling Institute’s Micronutrient Information Center.
According to Joe Beckman, a scientist who studies ALS at the Linus Pauling Institute, taking vitamin E does not extend life once ALS is diagnosed, but the progression of the disease may be slowed, according to a recent clinical study. In such studies, patients are not instructed on how to best take vitamin E to maximize absorption. Dr. Beckman hopes that these new results will encourage further trials with more rapid and efficacious supplementation. He also notes that this study provides more convincing evidence for a pathogenic role of oxidative stress in ALS.
Vitamin E may also protect against Alzheimer’s disease. A cross sectional study conducted in Cache County, Utah, and published in Annals of Neurology earlier this year showed that high intake of vitamin E and C together was associated with a substantially reduced incidence of Alzheimer’s disease. These two studies on ALS and Alzheimer’s provide accumulating evidence that antioxidant vitamins are important in the prevention of neurodegenerative diseases.