Morning coffee may give early Parkinson's brains an unexpected edge where everyday thinking starts to slip

Forgetting familiar faces, struggling to make simple decisions, or taking longer than usual to respond to stimuli are just a few examples of how cognitive decline can appear in everyday moments for many people with Parkinson's disease. However, the cup of coffee that kick-starts your morning may also help protect brain cells by lowering the risk of Parkinson's disease. Surprisingly, smoking—or more specifically, nicotine consumption—has been found to show a similar effect.

In a recent study, researchers from Chonnam National University Hospital, South Korea, wanted to know if these two things have a similar impact on cognitive decline. The findings are published in the journal Parkinsonism & Related Disorders.

Smoking did not show any association with cognitive benefits, but coffee drinking, on the other hand, was linked to better executive function in early Parkinson's disease (PD). People who drank a cup or more of the brown caffeinated beverage daily showed improved impulse control and mental calculation ability, along with a bonus of inhibition in PD.

A cup of Joe for better score

A 2025 Global Burden of Disease study projected that 25.2 million people could be living with Parkinson's disease worldwide by 2050, a nearly 112% increase from 2021. This progressive disorder of the nervous system is triggered by the loss of nerve cells in the substantia nigra—the part of the brain that governs movement, mood, learning, and decision-making. Neurons in this region are also responsible for chemical signaling and for producing dopamine, a crucial neurochemical that serves as a messenger between the brain and nervous system to control and coordinate body movements. As these nerve cells become damaged or die, dopamine levels drop, impairing the functions controlled by this region of the brain.

Another non-movement related prominent symptom of PD is a decline in cognitive performance. These issues occur across all stages of the disease and can significantly reduce a person's quality of life. Certain factors like the age or the stage of a disease that impact the decline are non-modifiable, but things like diet, sleep, mental health and habits that can affect cognition can still be monitored and regulated to a certain extent.

Intake of caffeine from coffee and nicotine from smoking has shown protective effects against the risk of developing PD. So, the researchers set out to examine how coffee and smoking might affect the thinking abilities of people with early Parkinson's disease. They studied 149 patients in the early stages of the disease who did not have dementia or other major brain disorders that could affect the results. Through structured interviews, the researchers asked about their coffee and smoking habits, including how much coffee they drank and how many packs they smoked per day. They also assessed the severity of physical symptoms of Parkinson's, such as tremors and stiffness.

Alongside standard memory, language and thinking evaluation, the team also assessed executive function—the mental skills used to manage everyday tasks. They used the Go/No-Go test, a cognitive assessment that measures a person's ability to respond to certain prompts (Go) while suppressing automatic or habitual reactions (No-Go).

At first, both coffee drinkers and smokers appeared to perform better across nearly all cognitive tests. The researchers later found that most coffee drinkers were younger and more educated, while smokers also tended to be male and more educated—factors that can independently influence cognitive performance. After adjusting for age, sex, and education, most of the cognitive benefits associated with smoking disappeared.

Coffee drinkers, when compared to non-drinkers, performed better on the Go/No-Go test, especially those who consumed more than one cup a day. They also showed slightly better performance in mental calculation tasks.

The results show how small lifestyle patterns and habits can impact the impairments faced by people with PD. The researchers, however, cautioned that while coffee may offer a small and specific benefit for certain aspects of cognitive function in early Parkinson's, its broader effects on memory and thinking should be interpreted carefully and not viewed as a cure-all for cognitive problems.