Diet rich in vitamin E may protect against Parkinson's disease

In a meta-analysis study to try to establish whether vitamin C, vitamin E, and carotene can lower the risk of Parkinson's disease (PD), scientists have found that diets rich in vitamin E could protect against the development of PD.

Before results can be confirmed however, a large randomised trial will be needed before any suggestions to changes in routine clinical practice can be implemented.

PD, a progressive neurodegenerative disease of unknown cause, possibly results from a combination of factors including ageing, genetic predisposition, and environmental exposures. While some studies suggest that diets rich in vitamin E are protective against PD, other studies show no such benefit.

Mayhar Etminan of the Royal Victoria Hospital, Quebec, Canada, and Centre for Clinical Epidemiology and Evaluation, Vancouver, Canada, and colleagues in their research searched for relevant studies from 1966 to March 2005.

The data from eight studies was combined and the team found that moderate dietary intake of vitamin E decreased the risk of developing PD. However, dietary vitamin C and carotene did not seem to produce any protective effects.

The authors say the role of vitamin E supplements is unclear, but at least one study suggests that synthetic supplements do not confer the same benefit as dietary sources.

Dr Etminan says in conclusion that the data suggests that diets rich in vitamin E protect against the development of PD, but no definite conclusions regarding the benefits of supplemental vitamin E can be made. Neither vitamin C nor carotene appear to have a neuroprotective effect. Dr Etminan says confirmation from well-designed randomised controlled trials is necessary before suggesting changes in routine clinical practice.

The report can be seen in the June issue of The Lancet Neurology published online today (Thursday May 19, 2005).