Dietary Intervention and Gastrointestinal Function in Patients With Parkinson's Disease

Not Applicable

Completed

Brief Summary: In this prospective, intervention study, participants with diagnosed Parkinson's disease will be instructed to follow a Mediterranean diet for five weeks. Gut permeability will be assessed using food-grade sugar molecules. Participants will provide urine and stool samples to assess gut permeability and microbial communities.

Recruitment & Eligibility

Inclusion Criteria

Physician-diagnosed Parkinson's disease aged 21-85 years
Hoehn & Yahr stage <3
Currently living in the same household with a healthy spouse/partner who meets study eligibility criteria and is willing to participate
Willing and able to complete informed consent in English
Willing to complete daily and weekly questionnaires and 6 dietary recalls over approximately 7 weeks
Willing to avoid beer, wine, and cocktails on the day before and the day of the sugar probe tests.
Willing to provide urine and stool samples during the study collection periods.
Willing and able to fast (no food or drink, except water or tea) for a prolonged period of time during study urine collections.
Willing to maintain usual diet through the pre-baseline period
Willing to make dietary changes to follow a Mediterranean dietary pattern during the intervention period.
Willing to discontinue taking prebiotic, fiber, probiotic, herbal, or high-dose vitamin or mineral supplements that may impact inflammation during the pre-baseline period and throughout the study protocol.
Willing to limit use of oral laxative medication to an "as-needed basis" (i.e. <3 times per week) during the full length of the study
Willing to avoid high intensity exercises two days prior to and the day of the permeability tests. These tests will be done on two occasions.
Willing to provide a social security number to receive study payment.

Arm && Interventions

Group	Intervention	Description
Mediterranean Diet	Mediterranean Diet	Participants will be given individualized diet education on the Mediterranean diet and instructed to follow the diet for the 5-week intervention period. Individualized diet education will be administered by a licensed, registered dietitian nutritionist (RDN) followed by weekly phone calls to ensure compliance, improve adherence to the diet and monitor for adverse events.

Primary Outcome Measures

Name	Time	Method
Gastroduodenal Permeability	Week 1; Week 5	The primary outcome is the change in gastroduodenal permeability induced by the Mediterranean diet. Gastroduodenal permeability will be assessed by measuring sucrose concentration in the 0 to 5-hour urine collection (end of intervention minus baseline)

Secondary Outcome Measures

Name	Time	Method
Stool Frequency	Week 1; Week 5	Difference in the average number of weekly stools (end of intervention compared to baseline)
Gastrointestinal Symptoms	Week 1; Week 5	Weekly GI symptoms assessed using the Gastrointestinal Symptom Rating Scale (GSRS). The GSRS consists of 15 questions related to 5 syndromes, constipation, diarrhea, reflux, abdominal pain, and indigestion. Symptoms are scored 1=no discomfort to 7=very severe discomfort. Scores from each of the 15 questions are summed for the total GSRS score.
Whole Gut Permeability	Week 1; Week 5	The change in sucralose/erythritol concentrations in a 0 to 24 hour urine collection (end of intervention minus baseline)
Colonic Permeability	Week 1; Week 5	The change in sucralose/erythritol concentrations in a 5 to 24 hour urine collection (end of intervention minus baseline)
Stool Consistency	Week 1; Week 5	Daily GI symptoms assessed using the Bristol Stool Scale (BSS). Difference in the average BSS (end of intervention compared to baseline).
Small Intestinal Permeability	Week 1; Week 5	The change in lactulose/rhamnose concentrations in a 5-hour urine collection (end of intervention minus baseline)