Intake of vitamin E, vitamin C, and carotenoids and the risk of Parkinsonʹs disease: a meta-analysis

Summary We studied the effect of vitamin C, vitamin E, and β carotene intake on the risk of Parkinsonʹs disease (PD). We did a systematic review and meta-analysis of observational studies published between 1966 and March 2005 searching MEDLINE, EMBASE, and the Cochrane Library. Eight studies were identified (six case-control, one cohort, and one cross-sectional). We found that dietary intake of vitamin E protects against PD. This protective influence was seen with both moderate intake (relative risk 0•81, 95% CI 0•67–0•98) and high intake (0•78, 0•57–1•06) of vitamin E, although the possible benefit associated with high intake of vitamin E was not significant. The studies did not suggest any protective effects associated with vitamin C or β carotene. We conclude that dietary vitamin E may have a neuroprotective effect attenuating the risk of PD. These results require confirmation in randomised controlled trials