A new study suggests that drinking coffee may protect patients against developing both Alzheimer's and Parkinson's disease.

The study was conducted by the Krembil Brain Institute, part of the Krembil Research Institute and three different types of coffee - light roast, dark roast, and decaffeinated dark roast- were investigated.

Dr Donald Weaver, Co-director of the Krembil Brain Institute, 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."

The research team identified a group of compounds known as phenylindanes, which emerge as a result of the roasting process for coffee beans. Phenylindanes are unique in that they are the only compound investigated in the study that prevent - or rather, inhibit - both 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.

Dr Ross Mancini, a research fellow in medicinal chemistry, said: "It's the first time anybody's investigated how phenylindanes interact with the proteins that are responsible for Alzheimer's and Parkinson's. 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."

The fact that it's a natural compound vs. synthetic is also a major advantage, says Dr Weaver. "What this study does is take the epidemiological evidence and try to refine it and to demonstrate that there are indeed components within coffee that are beneficial to warding off cognitive decline. It's interesting but are we suggesting that coffee is a cure? Absolutely not."