Could Measuring Salivary Caffeine Highlight Parkinson’s Progression?


Have you ever thought about whether measuring caffeine levels could give you insight into disease progression? Well according to Parkinson’s News Today, researchers have discovered a potential link between salivary caffeine and the progression of Parkinson’s disease. While past research discussed that caffeine may impact disease development, there was no actual understanding of the relationship between the two. Now, researchers have highlighted how evaluating these levels could provide more information about the illness progression. See the full study findings published in Scientific Reports.


What is caffeine? This natural stimulant is often found in coffee, cacao, and other sources. According to Coffee & Health:

Factors including smoking status, liver disease, alcohol consumption, some medications, and diet may all influence caffeine’s effect on an individual, with data suggesting that genetics also play a critical role…in how an individual reacts to caffeine. Caffeine is primarily metabolized in the liver by cytochrome P450 enzymes, which are responsible for more than 90% of caffeine clearance, [and the] enzyme responsible for metabolism of caffeine is coded for by the gene CYP1A2.

Researchers wanted to better understand the relationship between caffeine and Parkinson’s disease. Altogether, 98 patients – and 92 healthy controls – enrolled in the study. Of the patients, approximately 55% had moderate-to-advanced disease, while the remaining 45% had mild disease. To begin, researchers collected saliva samples from patients and controls. Next, researchers evaluated salivary caffeine levels. The research showed that:

  • Generally speaking, there were no significant differences in salivary caffeine between patients and healthy controls. In particular, there were no significant differences between patients with early/mild disease and healthy controls.
  • However, lower salivary levels were found in patients with more advanced cases, even though these same patients had normal caffeine metabolism and higher absorption.
  • Lower caffeine salivary levels correlated with more severe Parkinson’s disease cases and more severe motor-related symptoms.

As a result, researchers believe that salivary caffeine levels could be considered a potential biomarker for evaluating progression.

Parkinson’s disease

Parkinson’s disease, a central nervous system (CNS) disorder which impacts movement, typically occurs in five stages. In the first two stages, symptoms are relatively mild, encompassing tremors or muscle rigidity on one or both sides of the body. As Parkinson’s progresses into stage three, patients begin experiencing symptoms such as slowed movement and balance loss. In the final two stages, patients are unable to live independently. Some patients may also experience hallucinations, delusions, or other neurological symptoms.

Overall, the disease develops over time due to dopaminergic neuron loss. As dopamine-producing neurons in the substantia nigra disconnect and die, motor function is impaired. Doctors are unsure what causes dopaminergic neuron loss. However, genetics, Lewy bodies, and environmental factors are believed to play a role. While Parkinson’s disease can affect people of all ages, symptom onset usually occurs after 50 years old. Males are also more likely to develop the illness than females.

Symptoms include:

  • Muscle rigidity and stiffness
  • Fatigue
  • Tremors or trembling
  • Loss of automatic movements (smiling, blinking, chewing, swallowing)
  • Changes in speech, such as slurring or stuttering
  • Slowed movement
  • Poor or impaired balance, posture, and coordination
  • Depression and anxiety
  • Constipation
  • Loss of smell
  • Sleep interruptions
  • Hallucinations or other neuropsychiatric difficulties

Learn more about Parkinson’s disease here.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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