Mediterranean Diet Intervention to Improve Gastrointestinal Function in Parkinson's Disease a Randomized, Controlled, Clinical Trial

Mediterranean Diet Intervention to Improve Gastrointestinal Function in Parkinson's Disease: a Randomized, Controlled, Clinical Trial

This is a 10-week randomized, controlled study to investigate the effect of a Mediterranean diet intervention on gastrointestinal function in Parkinson's disease. After a 2-week run-in period, participants will be instructed to receive standard of care for constipation or receive standard of care + follow a Mediterranean diet for 8 weeks and answer daily and weekly questionnaires. Nutritional and neurological evaluations and stool samples will be collected at 0, 4 and 8 weeks.

Inclusion Criteria:

• Physician-diagnosed Parkinson's disease aged 40-85 years
• Drug naïve or on stable dosage of Parkinson's medications with no plans to change for the duration of the study protocol
• Hoehn & Yahr stage =<2.5 in the clinical "ON" state
• Constipation syndrome scores >=2.0 based on the GSRS
• Consume <20 grams of fiber daily based on the Block Fruit/Vegetable/Fiber screener
• Able to complete informed consent in English
• Willing to maintain habitual diet through the pre-baseline period.
• Willing to make dietary changes to follow a Mediterranean diet and/or receive standard of care for constipation during the intervention period.
• Willing to complete daily and weekly questionnaires and 12 dietary recalls over approximately 10 weeks.
• Able to provide stool samples during the study collection periods.
• Willing to avoid strenuous exercise and alcohol such as beer, wine, and cocktails 24 hours prior to each of the 3 study visits.
• Able to fast (no food or drink, except water, or decaf tea) at least 12 hours before each study visit
• Willing to discontinue taking prebiotic, herbal, or high-dose vitamin or mineral supplements that may impact inflammation during the pre-baseline period and throughout the study protocol.

Exclusion Criteria:

• Atypical or secondary Parkinsonism
• Underweight (BMI <18.5)
• History of deep brain stimulation (DBS) surgery
• Regular use of enemas or suppositories to alleviate constipation (e.g., >1 time per week)
• Use of another investigational product within 3 months of the screening visit
• Antibiotic or probiotic supplement use within 2 months from the day of stool collection
• Currently being treated for a physician-diagnosed GI disease or condition other than constipation, irritable bowel disease, gastroparesis, reflux or diverticular disease