Coffee drinking may diminish volume of striatum, key brain region
Significant change in healthy adults, but also in patients drinking a few cups daily
Heavier coffee drinkers, based on the number of cups consumed daily, have a lower volume of the striatum, a brain region affected in Parkinson’s disease, whether or not they have Parkinson’s, a study from China using MRI data reported.
Regular coffee consumption, without an emphasis on cups per day, also was tied to a significantly reduced volume in this brain region, but only among healthy adults rather than patients. Striatal volume was found to rise again in people who no longer were regular coffee drinkers.
The study, “Association of coffee consumption and striatal volume in patients with Parkinson’s disease and healthy controls,” was published in the journal CNS Neuroscience & Therapeutics.
Study challenges previously reported benefits of coffee consumption
Parkinson’s is marked by the loss of dopamine-producing neurons in a brain region called the substantia nigra, causing a deficit of dopamine in the striatum, a region involved in motor control. Dopamine is a neurotransmitter, a signaling molecule released by neurons that allows them to communicate with each other.
Previous studies have associated coffee with a reduced risk of Parkinson’s. But coffee consumption also has been associated with a decrease in the brain’s volume and functional connectivity.
Caffeine is known to enhance motor activity and ease dyskinesia (involuntary muscle movements) when acting upon the dopaminergic system.
“However, there have been few investigations about whether chronic coffee consumption is associated with the change in striatal volume,” the researchers wrote.
Scientists at centers in Hangzhou analyzed information from the Parkinson’s Progression Markers Initiative (PPMI) database to investigate the relationship between coffee consumption and changes in the volume of the striatum as a measure of neuronal degeneration in Parkinson’s.
PPMI is an ongoing, observational global study aiming to identify clinical, genetic, and other markers of Parkinson’s progression. Analyzed PPMI data — MRI scans and responses to questionnaires about coffee consumption — were obtained on July 1, 2022.
Information covering 130 newly diagnosed Parkinson’s patients and 69 healthy adults as a control group was included in the study.
Participants were divided into three subgroups according to their coffee consumption pattern: “current consumers,” people drinking a cup of caffeinated coffee at least once a week for at least six months; “ever consumers” or those who previously, but no longer, regularly drank coffee; and “never consumers” of the caffeinated beverage.
“Caffeine is one of the most widely consumed psychoactive substances, with an average consumption of about 200–250 mg/day/person, as a standard cup of coffee contains 100 mg of caffeine,” the study noted.
No significant differences in age or sex were evident between Parkinson’s patients and controls, or between people in the coffee consumption subgroups. Likewise, there were no differences regarding patients’ clinical characteristics.
MRI scans showed no significant differences in volume in all regions of the striatum between Parkinson’s disease patients and healthy controls.
Although this was surprising, the researchers noted that “the early stage of the disease may not result in a significant enough reduction in the total striatal [volume].”
Coffee consumption patterns also were not found to affect striatal volume in people with Parkinson’s.
Among healthy controls, however, current coffee consumers had a significantly lower volume across striatal regions than those who were ever consumers, who also showed a “tendency” for an increase in striatal volume. This “suggests that the chronic effects of caffeine on striatal morphology may fade and even compensate after quitting coffee,” the researchers wrote.
The number of cups consumed daily — the study looked at changes with one to at least four cups each day — by current drinkers negatively correlated with the volume of striatal regions in both Parkinson’s patients and controls.
After including factors that could influence dopaminergic neurons in the striatum and substantia nigra, such as age, sex or smoking status, current coffee consumption remained an independent predictor of a decrease in striatal volume among people without Parkinson’s.
A positive association between female sex and striatal volume was seen in Parkinson’s patients, suggesting that “male sex shows more severe atrophy and female sex confers protective benefits against neurodegeneration” in this disease, the researchers wrote.
“Our study provides evidence for the effect of chronic coffee consumption on striatal volume” in a living human brain, they concluded.
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