From the New Scientist, Do coffee and cigarettes protect against Parkinson's?
People with Parkinson's disease are less likely to be smokers and coffee drinkers than their healthy siblings, according to a study of family members. The finding adds to a growing body of evidence that some substance in tobacco might protect the brain against this devastating neurological disorder and sheds new light on coffee's effects on the disease.
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One possible mechanism involves a signalling chemical in the brain called dopamine. The death of dopamine-producing cells in the brain appears to drive the progression of Parkinson's disease, and both smoking and drinking coffee can raise levels of the chemical.
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Scott emphasises that the results of his study should not give anyone an excuse to start smoking. He says that the well-established risks of smoking – such as developing lung cancer or having a heart attack – "absolutely" outweigh any potential protection it might offer against Parkinson's.
"And relative to lung disease and heart disease, Parkinson's disease is far less common," he adds.