Vitamin E-Rich Diet Linked to Lowered Parkinson's Risk

Source: Tufts University
December 20, 2002 (Reviewed: December 16, 2004)

Oxidative stress has been implicated in the development of Parkinson's disease (PD). Research is focused on what role, if any, antioxidant nutrients may play in inhibiting the neural degeneration that marks the disease. In a recent issue of Neurology, Harvard School of Public Health researchers gauged the effect of antioxidant intake on the occurrence of PD among the participants of two large prospective studies.

Impact of diet

This current analysis involved more than 76,000 women of the Nurses' Health Study and more than 47,000 men enrolled in the Health Professionals Follow-Up Study. From food frequency questionnaires completed at 4-year intervals, the researchers tallied the participants' intake of vitamins C, E, and carotenoids and the use of vitamin supplements. During 14 years of follow-up, 161 women and 210 men were diagnosed with PD.

The researchers found no relationship between Parkinson's risk and intakes of vitamin C, carotenoids, multivitamins, or vitamin E supplements. An analysis of vitamin E intake from foods, though, showed that those in the highest intake quintile (12 IU/day for women and 15 IU/day for men) were at a substantially reduced risk than those with the lowest average intake of 8 to 9 IU/day (RR=0.68, 95% CI 0.49-0.93, p for trend 0.04).

Antioxidant value of vitamin E

Research in animals appears to support a protective role for vitamin E - several animal studies have demonstrated oxidation-induced nerve cell toxicity in the substantia nigra, the area of the brain affected by PD, and vitamin E-deficient rats have been shown to lose nigrostriatal nerve terminals.

However, studies in humans have produced inconsistent results. A cross-sectional study done in the Netherlands linked high vitamin E intake with a lowered PD risk, and several case control studies associated long-term intake of vitamin E-rich foods with a reduced risk of PD. But other studies, both case control and prospective, have found little or no effect.

Food vs supplements

The authors say that this current analysis provides strong evidence that vitamin E supplementation started during adulthood does not have a significant impact on the risk of Parkinson's. They propose that the reason vitamin E from foods showed an effect is that it represents long- term vitamin E intake. As nerve damage is fairly extensive by the time Parkinson's symptoms become apparent, the authors suggest that whatever protection is afforded by diet may begin early in life. There is also the possibility that other constituents of foods rich in vitamin E may provide the protective factor.

Source

• Intakes of vitamins E and C, carotenoids, vitamin supplements, and PD risk. SM. Zhang, MA. Hernan, H. Chen,  et al., Neurology, 2002, vol. 59, pp. 1161--1169

Related Links
Coenzyme Q10 May Help Parkinson's Disease
Antioxidants Shown to Reduce Alzheimer's Risk
Vitamin E May Slow Plaque Build-Up
To quickly access additional accurate information on this and other nutrition-related topics, visit Tufts University's Nutrition Navigator

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.