From: Rich Gauszka 


http://www.newscientist.com/article/dn11568-do-coffee-and-cigarettes-protect-ag
ainst-parkinsons.html

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.

Researchers say the study provides new evidence that the causes of
Parkinson's vary. They also stress that the negative health effects of
smoking far outweigh any protective effect the substance might have against
this neurodegenerative disease.

Parkinson's disease, which generally strikes people over the age of 50,
leads to a loss of coordination, dementia and may result in early death.

For decades, scientists have found evidence suggesting that smokers are
less likely to develop this illness than non-smokers. But experts believe
that genes can influence one's risk of developing Parkinson's, and the vast
majority of these studies involved participants who were unrelated and
therefore genetically dissimilar.

To control for this genetic variability, William Scott of the University of
Miami in Florida, US, and his colleagues studied the smoking and
coffee-drinking habits of Parkinson's patients and their family members.
....

Exactly why smoking and consuming coffee had an inverse association with
Parkinson's disease remains largely unclear. Dopamine link

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.

Scientists have also found some evidence that a substance in tobacco smoke
may boost dopamine levels by blocking the production of toxins that poison
dopamine-producing cells (see Why the wicked weed wards off Parkinson's).

But Scott cautions that the relationship between Parkinson's and smoking
may not be a simple one of cause and effect. The biology of certain
people's brains who develop Parkinson's disease may simply make them less
likely to become addicted to cigarettes, he says.

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