Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07213856

Nutritional Intervention for Constipation Symptoms in Patients With Parkinson's Disease

The goal of this clinical trial is to evaluate whether a dietitian-guided nutritional intervention can improve constipation symptoms in people with Parkinson's disease (PD). The main questions it aims to answer are:

* Can a dietitian-guided nutritional intervention increase the number of weekly bowel movements in individuals with PD and functional constipation? * Can this intervention positively influence gut microbiota composition, dietary intake, and nutritional status?

Researchers will compare the intervention group to a control group that will receive general dietary guidance only after the study period, to see if the intervention leads to improvements in bowel function and related health outcomes.

Participants will:

* Follow a diet plan developed by a dietitian, based on dietary reference intakes and tailored to the needs of individuals with PD and constipation * Participate in follow-up sessions with the dietitian for 3 months * Complete assessments at baseline, midpoint, and end of the intervention to evaluate bowel function, constipation symptoms, gut microbiota, nutritional status, and diet quality

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Parkinsons Disease (PD) Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Constipation Constipation - Functional Movement Disorders Nervous System Diseases Neurodegenerative Diseases Parkinson Disease Parkinsonian Disorders Pathological Conditions, Signs and Symptoms Signs and Symptoms Signs and Symptoms, Digestive Synucleinopathies

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hospital de Clínicas de Porto Alegre (HCPA)

Porto Alegre, Rio Grande do Sul, Brazil

Location status: Recruiting

Location contact

Juliana Heitich Brendler, Msc

SUB_INVESTIGATOR

Maira Rozenfeld Olchik, PhD

CONTACT

[email protected]

+55 (51) 33083020

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults with a previous diagnosis of Parkinson's disease
  • On a stable dose of levodopa for at least 3 months
  • Diagnosis of Functional Constipation by the Rome IV protocol

Exclusion criteria

  • Diagnosis of atypical or secondary parkinsonism
  • Hoehn and Yahr stage greater than 2
  • Presence of severe neurological or psychiatric disorders that impair the ability to participate in study procedures
  • Previous diagnosis of dementia
  • Presence of comorbidities such as active cancer, chronic obstructive pulmonary disease (COPD), heart failure, and/or chronic kidney disease
  • History of gastrointestinal cancers, inflammatory bowel diseases, or surgeries involving the gastrointestinal tract
  • Constipation secondary to clinical conditions such as hypothyroidism or diabetes mellitus
  • Use of opioids
  • Use of probiotics or antibiotics in the past 8 weeks
  • Continuous use of laxatives in the past 8 weeks
  • Presence of severe dysphagia according to the Functional Oral Intake Scale (FOIS)
  • Individuals receiving enteral or parenteral nutrition
  • Individuals under nutritional follow-up in the past 3 months

Treatment and study plan

Dietitian-Guided Nutritional Intervention

Behavioral

Participants receive a diet plan and nutritional counseling provided by a registered dietitian, based on a standardized protocol aligned with the Dietary Reference Intakes (DRIs) and adapted for the management of Parkinson's disease and constipation. The intervention includes follow-ups with the dietitian over a 3-month period.

Other names: Diet plan

Primary outcomes

  1. Change in weekly bowel movement frequency

    Time frame: Baseline and 90 days

    Mean change in the number of spontaneous bowel movements per week from baseline to 12 weeks, based on participant-reported bowel diaries.

Secondary outcomes

  1. Change in relative abundance of gut microbial taxa

    Time frame: Baseline and 90 days

    Change in the relative abundance of selected bacterial genera associated with constipation and Parkinson's disease, measured by 16S rRNA sequencing of stool samples.

Other outcomes

  1. Change in dietary intake

    Time frame: Baseline, 45 days and 90 days

    Variation in intake of macronutrients and fiber, assessed through 24h food records.

Study contacts

Contact information is provided by the study sponsor or research team.

Maira Rozenfeld Olchik, PhD

CONTACT

[email protected]

+55 (51) 33083020

Sponsors and collaborators

Lead sponsor

Hospital de Clinicas de Porto Alegre

Other

Registry information

Official study title

Nutritional Intervention for Constipation Symptoms in Patients With Parkinson's Disease: A Randomized Clinical Trial

Acronym: NUTRI-GUT-PD

Important dates

Study start
2026
Primary completion
2027
Study completion
2029
First posted
Oct 9, 2025
Registry last updated
Jun 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.