Researchers claim that one cup of coffee per morning could be ward of dementia and Parkinson's.
The benefits are particularly strong for people who opt for darker roasted beans if it's decaffeinated, the study found.
The coffee roasting process releases chemicals which counter the responsible proteins for the development of diseases, scientists discovered.
It is not a cure or clear prevention for either disease, but it doesn't hurt to add a cup to your daily routine, reports the Daily Mail.
Roasting coffee beans triggers release of phenylindanes, a group of compounds which prevent the "clumping" of common proteins in Alzheimer's and Parkinson's.
Alzheimer's develops when these proteins, beta amyloid and tau, clump together between neurons.
Study lead Dr. Donald Weaver, co-director of the Krembil Brain Institute in Canada, said: "Coffee consumption does seem to have some correlation to a decreased risk of developing Alzheimer's disease and Parkinson's disease.
"But we know why that is, which compounds are involved and how they may age-related cognitive decline.
"The caffeinated and decaffeinated dark roasts have had identical potencies in our initial experimental tests.
"So we observed early on that the protective effect could not be due to caffeine."
Dr. Weaver, Dr. Ross Mancini and Dr. Yanfei Wang, tested phenyls and dark roast and decaffeinated dark roast coffees.
They discovered levels of the chemical – and the degree of protection – was increased by the coffee was roasted.
Dr Weaver said: "So phenylindanes are a dual-inhibitor. Very interesting, we were not expecting that."
Dr Mancini added: "It's the first time anybody investigated how phenylans interact with the proteins that are responsible for Alzheimer's and Parkinson's.
"The next step would be to investigate how the beneficial compounds are, and whether they have the ability to enter the bloodstream, or cross the blood-brain barrier.
"The fact that it's a compound natural versus synthetic is also a major advantage," said Dr. Weaver.
He said: "Mother Nature is a much better chemist than we are and Mother Nature is able to make these compounds.
"If you have a complicated compound, it's a great idea to grow it in a crop, harvest the crop, grind the crop out and extract it from try to make it."
But more research is needed to translate into potential therapeutic options, they said.
Dr. Weaver added: "What this study does is take epidemiological evidence and try to refine it and to demonstrate that there are indeed components within the coffee that are beneficial to ward off cognitive decline.
"It's interesting but we are suggesting that coffee is cure? Absolutely not."