Parkinson’s disease (PD) is a neurodegenerative disorder associated with a loss of nerve cells that produce dopamine. Those with PD may experience tremors, slow movement, muscle rigidity and difficulty walking. Additionally, many patients are plagued with a variety of secondary complications from the disease.
Gastric dysmotility, or delayed gastric emptying, is a common disorder that newly diagnosed PD patients develop. Scientists believe that degeneration of the myenteric plexus, which is responsible for stimulating gut movement, is responsible for this condition.
Past research has shown that vitamin D levels are lower in Parkinson’s patients compared to their healthy counter parts. Additionally, vitamin D has been proven to prevent the progression and deterioration of Parkinson’s disease. Since scientists have discovered that vitamin D receptors are most strongly expressed in dopamine-rich regions of the brain, researchers believe that this may explain the neuroprotective role of vitamin D in several brain disorders, including PD. However, no studies to date have evaluated whether a relationship exists between vitamin D status and delayed gastric emptying.
Therefore, in a new study, researchers aimed to determine the relationship between vitamin D status and gastrointestinal health in newly diagnosed PD patients who have yet to be prescribed medication to treat the disease. Those with a history of delayed gastric emptying time or altered serum vitamin D levels due to a preexisting condition, supplementation or medication use were excluded from the study.
A total of 51 drug-naïve newly diagnosed Parkinson’s patients and 20 age-matched healthy controls were included in the study. The researchers gathered the participant’s demographic information and measured several blood parameters relating to vitamin D status, liver and kidney function and markers for inflammation. The researchers used scintigraphy to assess the gastric emptying time (GET) of the participants. Scintigraphy is a diagnostic test which uses radioisotopes to evaluate an organ’s function. Disease severity and cognitive function were evaluated using three standard tools of assessment: Unified Parkinson’s Disease Rating Scale-III (UPDRS-III), the Hoehn and Yahr stage and the mini-mental state examination for Koreans (MMSE-K).
Here is what the researchers found:
- Patients with delayed GET had a lower vitamin D status compared to PD patients with normal GET and healthy controls (11.59 ± 4.90 ng/ml vs. 19.43 ± 6.91 and 32.69 ± 4.93 ng/ml, respectively, p < 0.01).
- Serum 25(OH)D levels were negatively correlated with GET in PD patients (p < 0.05); however, no significant relationship existed between vitamin D status and GET in healthy controls.
- Vitamin D status was associated with a 17% decreased odds of delayed GET in those with PD (OR: 0.83; p < 0.05).
The researchers concluded,
“The current study is the first to reveal the association between 25-hydroxyvitamin D3 levels and GET in PD patients, and our results suggest that 25-hydroxyvitamin D3 deficiency may be an independent factor for gastric dysmotility in PD.”
The study was limited by its observational design and relatively small sample size. Therefore, the researchers emphasized the need for large scaled prospective studies in order to investigate the mechanism behind vitamin D and gastric emptying in newly diagnosed, drug-naïve PD patients. They also recommend future trials take place to determine if vitamin D supplementation may provide a therapeutic effect on delayed GET in Parkinson’s patients.
Sturges, M. Low vitamin D status associated with gastric dysmotility in newly diagnosed Parkinson’s patients. The Vitamin D Council Blog & Newsletter, 2016.