If you have walked by your local Starbucks or any coffee shop during the scramble of commuters trying to get to work, the line around the block is a clear indication that Americans love their morning Joe.

According to a 2018 Reuters survey commissioned by the National Coffee Association, it was found that 64% of Americans drink a cup of java daily. And based on current research, that may not be a bad thing, as drinking coffee regularly may help to protect brains from neurodegenerative diseases like Alzheimer's disease and Parkinson's disease.

Alzheimer’s disease — the most common cause of dementia in the older population — affects approximately 5.8 million people in the U.S., while Parkinson’s affects roughly 1 million.

The connection to Alzheimer’s and Parkinson’s

For many years, studies have found links suggesting consumption of coffee can lead to possible protective effects in the brain. With Alzheimer’s disease and Parkinson’s disease both being neurodegenerative conditions that are known to be protein-misfolding diseases, this allows researchers to investigate coffee’s influence simultaneously.

In a study published last year, researchers took a deep dive into discovering why and which compounds in coffee are involved — as well as any potential impact.

“In our study, we show that a class of compounds (phenylindanes) from roasted coffee has the ability to inhibit the misfolding of two proteins (beta-amyloid, tau) whose misfolding and aggregation (‘clumping’) is implicated in the disease process of [Alzheimer’s disease],” says Dr. Donald Weaver, the study’s lead author and a neurologist and medical director at Krembil Brain Institute, University Health Network. “Phenylindanes are unique in that they are the only compound investigated in the study that inhibits both beta-amyloid and tau — two protein fragments common in Alzheimer's and Parkinson's — from clumping.”

Caffeine may not be answer

While previous research has linked coffee’s caffeine content to having a protective effect, Weaver and his team took a different approach as they instead investigated light roast, dark roast and decaffeinated dark roast coffee extracts.

It appears that phenylindanes, which are created during the roasting process, may be the catalyst. The caffeinated and decaffeinated dark roast both yielded the same protective effect, leading researchers to negate caffeine. And since roasting leads to higher quantities of phenylindanes, darker roasts were found to be more protective than lighter roasts.

More work needs to be done

Before running out and stocking up on coffee beans, researchers caution this is just the start to what they know, and further studies are needed.

Most significantly, based on these findings, researchers need to ascertain if phenylindanes can get into the brain from just consuming a cup of coffee.

“That question remains unanswered,” Weaver says. “If they don’t have the ability to cross the blood-brain barrier and get into the brain, then clearly they are not the explanation.”

Still, coffee can offer short-term improvements in alertness and attention. Plus, following tips from the Alzheimer’s Association can support mental health, staying active and socially involved, and exercising the brain by learning new things.