BY SARAH OWENS
People with early-stage Parkinson's disease had low levels of caffeine and caffeine metabolites in their blood compared to healthy controls, suggesting that caffeine levels may be used to diagnose people with Parkinson's, according to a new study published online on January 3 in Neurology.
The Caffeine-Parkinson's Link
Previous research suggests that caffeine may protect the brain against Parkinson's disease. People who consumed more caffeine daily appeared to have a decreased risk of developing the disease, and vice versa. In addition, preliminary animal studies suggest that caffeine may protect against degeneration in the substantia nigra, an area of the brain implicated in Parkinson's.
Checking Caffeine Levels
To investigate the association between how caffeine is metabolized in the body and Parkinson's symptoms, researchers in the department of neurology, the Research Institute for Diseases of Old Age, and the Laboratory of Proteomics and Biomolecular Science at Juntendo University School of Medicine in Tokyo, Japan enrolled 108 patients with early-stage Parkinson's and 31 age-matched healthy controls.
After collecting blood serum samples from all participants, researchers used a lab technique to analyze levels of caffeine and 11 caffeine metabolites, chemicals left behind when caffeine is used for energy by the body. They also asked the participants to report how many cups of caffeinated beverages they consumed per day.
Finally, the researchers compared the results on the blood serum analyses with the participants' disease status (Parkinson's or healthy) and the severity of their Parkinson's symptoms, as measured by two scales that rate stage and severity of the disease.
A Potential Diagnostic Tool
The researchers found that caffeine levels in the blood samples, and levels of 9 of the 11 caffeine metabolites measured, were elevated in patients with Parkinson's disease compared to the healthy controls. The associations remained significant regardless of the participants' total daily caffeine intake, the severity of their symptoms, their sex, and whether or not they carried genes that predisposed them to Parkinson's.
The authors concluded that their findings "indicate a neuroprotective effect of caffeine" and suggest that caffeine levels, as measured through blood serum tests, may be a reliable way to help diagnose Parkinson's disease.