英文版（原文）

Dark-roast coffee may prevent Alzheimer's and Parkinson's

For years, scientists have suspected that drinking coffee helps lessen the chances of getting Alzheimer's and Parkinson's diseases. A new study indicates that this may indeed be the case, and that the darker the roast, the better it works.

Led by Dr. Donald Weaver, scientists at Canada's Krembil Brain Institute compared three types of Starbucks 100-percent Arabica instant coffee – light roast, dark roast, and decaffeinated dark roast.

In in vitro (glass dish) tests, it was found that the two dark roasts were both particularly effective at keeping the protein fragments beta amyloid and tau from clumping. The clumping of these fragments within the brain is believed to be a key cause of both Alzheimer's and Parkinson's.

Of all the compounds that were analyzed in the coffees tested, there was only one – a group known as phenylindanes – that had the anti-clumping effect. The longer a coffee is roasted, the greater the amount of phenylindanes it contains, thus the more potent the effect is. Interestingly, the caffeinated and decaffeinated dark roasts were equally potent, indicating that caffeine content is irrelevant (that said, a study recently conducted at Indiana University Bloomington suggests that caffeine is effective at warding off dementia).

"It's the first time anybody's investigated how phenylindanes interact with the proteins that are responsible for Alzheimer's and Parkinson's," says Dr. Ross Mancini, who (along with biologist Yanfei Wang) assisted Weaver in the research. "The next step would be to investigate how beneficial these compounds are, and whether they have the ability to enter the bloodstream, or cross the blood-brain barrier."

A paper on the study was recently published in the journal Frontiers in Neuroscience.