According to the Krembil Brain Institute, specific compounds created in the process of roasting coffee beans help stave off the debilitating diseases.
The Canada-based researchers looked into three different types of coffee – light roast, dark roast and decaffeinated dark roast.
Dr. Donald Weaver, the study’s lead author, said: “Coffee consumption does seem to have some correlation to a decreased risk of developing Alzheimer’s disease and Parkinson’s disease.
“But we wanted to investigate why that is – which compounds are involved and how they may impact age-related cognitive decline.”
He added: “The caffeinated and de-caffeinated dark roast both had identical potencies in our initial experimental tests. So we observed early on that its protective effect could not be due to caffeine.”
The researchers then identified a group of compounds known as phenylindanes, which are created during the roasting process.
Phenylindanes are the only compound investigated in the study that inhibit beta amyloid and tau, two protein fragments common in Alzheimer’s and Parkinson’s, from clumping.
As roasting leads to higher quantities of phenylindanes, dark roasted coffee appears to be more protective than light roasted coffee.
“It’s the first time anybody’s investigated how phenylindanes interact with the proteins that are responsible for Alzheimer’s and Parkinson’s,” added Weaver.
“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.”