A diet rich in vitamin E could protect against Parkinson's disease, believe researchers. Good sources of vitamin E include green leafy vegetables, nuts and vegetable oils.
A study in Lancet Neurology pooled available data and found people who ate plenty of these foods in their diet were far less likely to develop Parkinson's. The authors said it was impossible to tell if supplements would do the same.
Dr Mayhar Etminan, from Queen's University in Canada, and colleagues scrutinised eight studies published between 1966 and 2005 looking at the effects of vitamins E and C, and the nutrient beta carotene.
Both moderate and high doses of vitamin E appeared to reduce the risk of Parkinson's. Neither vitamin C or beta carotene had a similar effect, however.
Dr Etminan said: "Our data suggest that diets rich in vitamin E protect against the development of Parkinson's disease."
But he added: "No definite conclusions regarding the benefits of supplemental vitamin E can be made.
"Given that these data are observational, confirmation from well-designed randomised controlled trial is necessary before suggesting changes in routine clinical practice."
A spokesman from the Parkinson's Disease Society agreed. He cautioned against people rushing out and buying lots of vitamin E supplements to ward of Parkinson's. In high doses, vitamin E can be toxic.
"It is an interesting finding, but we would like to see more robust trials undertaken.
"We recommend a healthy, balanced diet rich in green leafy vegetables, olive oil, seeds and nuts to give people a good vitamin E intake," he said.
Vitamin E is a powerful antioxidant and appears to guard the body from the damaging effects of reactive oxygen molecules called free radicals.