Consuming foods high in vitamin E could reduce the risk of developing Parkinson's disease, says a study published in the Oct. 22, 2002 issue of Neurology, a journal of the American Academy of Neurology.
Researchers examined the effects of consuming not only vitamin E, but also vitamin C and carotenoids, both from food and dietary supplements. The study was led by Dr. Shumin Zhang, assistant professor of epidemiology and medicine at Harvard School of Public Health in Boston.
"Vitamin E is a strong antioxidant, so vitamin E could protect the cells from oxidative stress, so potentially, vitamin E can reduce the risk of Parkinson's disease," Zhang said.
Zhang and colleagues looked at the records of 76,890 women from the Nurses' Health Study and 47,331 men from the Health Professionals Follow-Up Study and analyzed the dietary habits and medical status of the study participants. The two studies were established nearly two decades ago to follow the lifestyles of thousands of people on a long-term basis with the goal of studying information that could further medical science.
By 1998, there were 371 cases of Parkinson's disease, a debilitating disease caused by an imbalance in brain chemicals. There were 161 cases among the women's group and 210 among the men. The illness is characterized by loss of motor skills that can trigger body tremors.
Researchers found taking standard vitamin supplements had no effect on Parkinson's disease. However, those who routinely consumed a greater amount of foods rich in vitamin E, such as nuts, did appear to have a lower risk.
Although it cannot as yet be determined how much vitamin E is necessary, Zhang said including sufficient levels of vitamin E in a balanced diet is a good start.
Vitamin E has been looked at in Parkinson's disease before and also in another degenerative disease that attacks the brain, Alzheimer's, explained Dr. Burton Scott, a neurologist and assistant professor of clinical neurology at Duke University Medical Center in Durham, N.C. Previous studies have found vitamin E tablets to have no effect on Parkinson's, but foods high in vitamin E may be a different story, Scott said.
"The vitamin E [alpha-tocopherol found in most multivitamins] may not be the main player in what's having the effect," Scott told UPI. Instead, it could be the action of the whole food that's contributing to this benefit. Likewise, it may not be the d-alpha tocopherol form of vitamin E commonly found in Vitamin E supplements that creates the beneficial effect, but a combination of various forms of vitamin E tocopherols and tocotrienols, such as d-Beta, d-Gamma, d-Delta, as well as d-Alpha found in food and a very few premier multivitamins.
At present, about 1 million people in the United States have Parkinson's disease, Scott said. Former U.S. Attorney General Janet Reno, boxer Muhammad Ali, Pope John Paul II and actor Michael J. Fox all have this illness.
Background: Oxidative damage has been implicated in the pathogenesis of PD. Limited and mostly retrospective epidemiologic data suggest a reduction or no change in risk of PD associated with high vitamin E intake.
Objective: To examine prospectively the associations between intakes of vitamins E and C, carotenoids, vitamin supplements, and risk of PD.
Methods: The authors documented the occurrence of PD within two large cohorts of men and women who completed detailed and validated semiquantitative food frequency questionnaires. A total of 371 incident PD cases were ascertained in the Nurses’ Health Study, which comprised 76,890 women who were followed for 14 years, and the Health Professionals Follow-Up Study, which comprised 47,331 men who were followed for 12 years.
Results: Neither intake of total vitamins E or C or use of vitamin E or vitamin C supplements or multivitamins was significantly associated with risk of PD. The risk of PD, however, was significantly reduced among men and women with high intake of dietary vitamin E (from foods only). The pooled multivariate relative risk (RR) comparing individuals in the highest quintile with those in the lowest quintile was 0.68 (95% CI, 0.49 to 0.93). Consumption of nuts was also significantly associated with a reduced risk of PD (for 5/week vs <1/month, pooled RR, 0.57; 95% CI, 0.34 to 0.95). Intakes of dietary vitamin C and carotenoids were not significantly associated with risk of PD.
Conclusions: Use of vitamin supplements and high intake of carotenoids do not appear to reduce the risk of PD. The reduction in risk of PD associated with high dietary vitamin E intake suggests that other constituents of foods rich in vitamin E may be protective. Alternatively, moderate amounts of vitamin E may reduce risk of PD, but this benefit may be lost with higher intakes.
S.M. Zhang, M.A. Hernán, H. Chen, D. Spiegelman, W.C. Willett, and A. Ascherio
Intakes of vitamins E and C, carotenoids, vitamin supplements, and PD risk; Neurology 2002 59: 1161-1169.