Optimizing Protein Patterns for Skeletal Muscle Preservation and Sleep in the Medical Management of Parkinson Disease

The purpose of this pilot study is to generate preliminary data on the impact of the dietary protein pattern on markers of skeletal muscle health and drug efficacy in Parkinson disease.

Study Overview

• Status: Completed
• Conditions: Parkinson Disease
• Intervention / Treatment: Behavioral: Protein Redistribution Diet; Behavioral: Protein Consistent Diet

Detailed Description

Parkinson's disease (PD) is a complex neurological disease that affects ~6.1 million people worldwide - mostly older adults >60 years. The most effective treatment for PD is dopaminergic therapy, particularly levodopa (Ldopa). People with PD have variable responses to Ldopa, including degrees of motor fluctuations (MF) throughout the day. The half-life of Ldopa is ~1.5 h and therefore, dosage and timing are essential to mitigate MF. Ldopa is a large neutral amino acid (LNAA), and the bioavailability of Ldopa is compromised when simultaneously ingested with LNAA (e.g., leucine). Both Ldopa and LNAAs from food are absorbed through the same intestinal transporter, but LNAAs from food are preferentially absorbed by the enterocyte, limiting the bioavailability of Ldopa. Thus, the scientific community often recommends the protein-redistribution diet (PRD). With PRD, patients limit protein (<10 g) at the desired time of medication efficacy (daytime) and meet their protein needs during the evening meal (~70+g). There are deleterious implications of the PRD for older adults with PD; consumption of >30 g of protein, in a single meal, will not sufficiently increase muscle protein synthesis. Additionally, the impact of the PRD on skeletal muscle quality and function has not been determined, and it is unclear, based on prior studies, whether the PRD enhanced drug absorption. Therefore, the objective of this study is to address these gaps in knowledge. This study will quantify the effects of dietary protein pattern on skeletal muscle in PD; determine the effects of dietary protein pattern on sleep quality in PD. This study is an acute, 5-week, crossover intervention with PD participants randomly assigned to first adhere to either the PCD or PRD. Participants will receive diet prescriptions and meal plans for their respective diet, and outcome measures will be assessed at days 0, 14, 21, and 35.

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35233
      • University of Alabama at Birmingham

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Clinical diagnosis of idiopathic PD for 5 or more years
• 45 years or older
• On a stable levodopa regimen for 3 or more months
• Self-reported to experience motor fluctuations

Exclusion Criteria:

• Following a specific diet that would preclude participation
• Renal disease
• Deep brain stimulation
• Known narcolepsy
• Untreated sleep apnea
• Any condition that, in the opinion of the investigator, will preclude the participant from successfully or safely completing study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Protein Redistribution Diet; PD participants may first be randomized to follow the Protein Redistribution Diet followed by the Protein Consistent Diet.	Behavioral: Protein Redistribution Diet; PD participants will be instructed by a Registered Dietitian to consume 10 grams or less of protein until their evening meal. They will then consume a high protein evening meal to meet their protein needs. They will receive one-on-one education and supportive materials to follow diet plan.; Other Names: PRD
Active Comparator: Protein Consistent Diet; PD participants may first be randomized to follow the Protein Consistent Diet followed by the Protein Redistribution Diet.	Behavioral: Protein Consistent Diet; PD participants will be instructed by a Registered Dietitian to consume 20-30 grams of protein per meal. They will receive one-on-one education and supportive materials to follow diet plan.; Other Names: PCD

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Markers of Skeletal Muscle Metabolism GDF15	Serum Growth Differentiation Factor 15 (GDF15)	Baseline to 5 weeks
Change in Markers of Skeletal Muscle Metabolism FGF21	Serum Fibroblast Growth Factor 21 (FGF21)	Baseline to 5 weeks
Change in Handgrip Strength	Handgrip strength assessed via digital dynamometer	Baseline to 5 weeks
Change in Sleep Efficiency	Sleep efficiency assessed via actigraphy	Baseline to 5 weeks
Change in Motor Symptoms	Motor symptoms assessed via the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II. Part II ranges from 0-52 with higher scores indicating greater symptom severity.	Baseline to 5 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Physical Activity	Physical activity assessed via actigraphy	Baseline to 5 weeks
Change in Total Parkinson Symptoms	Parkinson-related symptoms assessed by total MDS-UPDRS score	Baseline to 5 weeks. Total score ranges from 0-260 with higher scores indicating greater symptom severity.

Collaborators and Investigators

• Sponsor: University of Alabama at Birmingham
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Christine C Ferguson, PhD, University of Alabama at Birmingham

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2022
• Primary Completion (Actual): November 25, 2024
• Study Completion (Actual): November 25, 2024

Study Registration Dates

• First Submitted: June 23, 2022
• First Submitted That Met QC Criteria: June 23, 2022
• First Posted (Actual): June 29, 2022

Study Record Updates

• Last Update Posted (Actual): June 15, 2025
• Last Update Submitted That Met QC Criteria: June 13, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: Sleep; Diet; Parkinson Disease; Protein; Skeletal Muscle
• Additional Relevant MeSH Terms: Synucleinopathies; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurodegenerative Diseases; Movement Disorders; Parkinsonian Disorders; Basal Ganglia Diseases; Parkinson Disease
• Other Study ID Numbers: IRB-300009538; P30DK056336 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No