NCT06130956

Brief Summary

Rationale: Protein from plant-based foods may be unable to stimulate protein synthesis due to a suboptimal essential amino acid content and a lower digestibility. However, a more optimal amino acid profile may be achieved by increasing portions sizes and blending multiple plant-based sources. Studies investigating the anabolic properties of vegan diets (total elimination of animal-based foods) rather than single plant-based foods in older adults are scarce. It remains unknown if a vegan diet can also affect protein synthesis rates in other musculoskeletal tissues than muscle. Primary objective: To assess the effects of a 2-week preoperative vegan diet in comparison to an omnivorous diet on protein synthesis rates in Hoffa's fat pad, synovium, tendon, bone, ligaments, menisci, and cartilage in older adults with knee osteoarthritis undergoing total knee arthroplasty. Secondary objective: To assess the effects of a 2-week preoperative vegan diet in comparison to an omnivorous diet on blood pressure and plasma amino acids in older adults with knee osteoarthritis undergoing total knee arthroplasty. Study design: Multi-center, randomized, controlled trial with an intervention and a control group. Study population: 40 older adults (60 - 80 years) with osteoarthritis of the knee undergoing total knee replacement. Intervention: Controlled vegan diet versus controlled omnivorous diet, for a duration of 14 days. Main study parameters/endpoints: Primary study parameters are protein synthesis rates of Hoffa's fat pad, synovium, tendon, bone, ligament, menisci, and cartilage. Secondary parameters include blood pressure and plasma amino acids.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
40

participants targeted

Target at P25-P50 for not_applicable

Timeline
7mo left

Started Oct 2024

Typical duration for not_applicable

Geographic Reach
1 country

2 active sites

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress73%
Oct 2024Dec 2026

First Submitted

Initial submission to the registry

November 8, 2023

Completed
6 days until next milestone

First Posted

Study publicly available on registry

November 14, 2023

Completed
11 months until next milestone

Study Start

First participant enrolled

October 22, 2024

Completed
2.1 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2026

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2026

Last Updated

April 1, 2025

Status Verified

March 1, 2025

Enrollment Period

2.1 years

First QC Date

November 8, 2023

Last Update Submit

March 25, 2025

Conditions

Outcome Measures

Primary Outcomes (1)

  • Change in tissue-specific protein synthesis rates

    Tissue-specific protein synthesis rates in the knee using D2O dosing methodology

    During the 2-week preoperative period

Secondary Outcomes (2)

  • Change in blood pressure

    Measured at baseline and 1 day before surgery

  • Change in plasma amino acids

    During the 2-week preoperative period

Study Arms (2)

Vegan group

EXPERIMENTAL

Subjects in the vegan group will receive a vegan diet during the 2-week preoperative period.

Dietary Supplement: Vegan diet

Omnivorous group

ACTIVE COMPARATOR

Subjects in the omnivorous group will receive an omnivorous diet during the 2-week preoperative period.

Dietary Supplement: Omnivorous diet

Interventions

Vegan dietDIETARY_SUPPLEMENT

Vegan diet for 2 weeks before surgery

Vegan group
Omnivorous dietDIETARY_SUPPLEMENT

Omnivorous diet for 2 weeks before surgery

Omnivorous group

Eligibility Criteria

Age60 Years - 80 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Written informed consent;
  • Patients scheduled for total knee arthroplasty;
  • BMI between 20-32 kg/m2;
  • Aged 60 - 80 years;
  • Mentally competent, as judged by the treating physician;

You may not qualify if:

  • Following a vegetarian or vegan diet or a diet that affects protein intake during the six months prior to the study;
  • Participating in a structured progressive exercise training program in the past three months;
  • Lost more than 4 kg body weight during three months prior to the study;
  • Chronic use of medications that affect protein metabolism (i.e. systemic corticosteroids, or prescription strength acne medications);
  • Being diagnosed with one of the following: diabetes mellitus, rheumatoid arthritis, peripheral artery disease Fontaine III or IV, COPD GOLD III or IV, neoadjuvant chemotherapy or radiotherapy, phenylketonuria, collagen disorders (e.g. Marfan and Ehler-Danlos);
  • Alcohol abuse;
  • Surgical intervention to the knee in the past four weeks;
  • Total parenteral nutrition at day of surgery;
  • Glomerular filtration rate (GFR) \<20 mL/min/1.73 m2;
  • Allergic or intolerant to any product included in the diets;
  • Osteoarthritis of the knee secondary to septic arthritis, osteonecrosis, fracture, osteochondritis dissecans, or malignant processes;
  • Any other medical condition that may interfere with the safety of the participants or the outcome parameters, in the investigators judgement;
  • Not willing to stop nutritional supplements, with the exception of vitamin D and supplements on medical advice.
  • Investigator's uncertainty about the willingness or ability of the participant to comply with the protocol instructions;
  • Participation in other studies that may have an impact on the outcomes during the three months before the start of the current study.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (2)

Rijnstate Hospital

Arnhem, Netherlands

RECRUITING

Hospital Gelderse Vallei

Ede, Netherlands

RECRUITING

MeSH Terms

Interventions

Diet, Vegan

Intervention Hierarchy (Ancestors)

Diet, VegetarianDiet, Plant-BasedDiet TherapyNutrition TherapyTherapeuticsDietNutritional Physiological PhenomenaDiet, Food, and NutritionPhysiological Phenomena

Study Officials

  • Lisette de Groot, PhD

    Wageningen University

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Inge Groenendijk, PhD

CONTACT

Lisette de Groot, PhD

CONTACT

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
prof.dr.ir.

Study Record Dates

First Submitted

November 8, 2023

First Posted

November 14, 2023

Study Start

October 22, 2024

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Last Updated

April 1, 2025

Record last verified: 2025-03

Data Sharing

IPD Sharing
Will not share

Locations