Research indicates that regular high caffeine consumption affects dopamine function in patients with Parkinson’s disease. This comes from work undertaken at the University of Turku and Turku University Hospital in Finland.
Parkinson’s disease is a condition in which parts of the brain become progressively damaged over many years.
Earlier epidemiological studies indicate that regular caffeine intake is associated with a reduced risk of developing Parkinson’s disease. The new study considers the effects of caffeine on disease progression in patients who have already been diagnosed with the disease.
The new research was based on a clinical study compared 163 patients with early-stage Parkinson’s disease to 40 healthy controls. The examinations and imaging were conducted on two occasions for a subsample, with an average interval of six years between the first and second imaging session.
The dopamine function of the brain was assessed with single photon emission computed tomography (SPECT) to measure dopamine transporter (DAT) binding.
The researchers examined changes in brain dopamine transporter binding, compared with patients’ caffeine consumption, which was assessed both by a validated questionnaire and by determining concentrations of caffeine and its metabolites in blood samples.
The findings revealed that patients with a high caffeine consumption exhibited a 8.3–15.4 percent greater decrease in dopamine transporter binding compared to those with a low caffeine consumption.
The observed decline in dopamine function is more likely to be a downregulatory compensatory mechanism in the brain that has also been observed in healthy individuals following caffeine and other stimulant use.
According to lead researcher Valtteri Kaasinen, Professor of Neurology at the University of Turku: “While caffeine may offer certain benefits in reducing risk of Parkinson’s disease, our study suggests that high caffeine intake has no benefit on the dopamine systems in already diagnosed patients. A high caffeine intake did not result in reduced symptoms of the disease, such as improved motor function.”
The results further suggest that caffeine consumption before undergoing diagnostic brain dopamine imaging may also affect the imaging results. This could potentially complicate the interpretation of clinically commonly used brain imaging results.
Hence, the research results suggest that patients should refrain from consuming coffee and caffeine for 24 hours before undergoing diagnostic DAT imaging.
The research results have been published in the Annals of Neurology journal, titled “Dietary Caffeine and Brain DopaminergicFunction in Parkinson Disease.”
