Effects of Vitamin C on Skeletal Muscle (VICS)

A Crossover Pilot Study on the Effects of Vitamin C Supplementation on Skeletal Muscle in Older Women (VICS)

As part of the ageing process muscles become weaker. One of the reasons for this is that mitochondria, the 'engines' that provide energy to fuel muscles, age and work less efficiently. Mitochondria are found in almost all cells in the human body. Mitochondria take in nutrients that are provided from food and break these down to create energy-rich compounds to fuel many different processes in the body. Muscles are loaded with mitochondria because they require a lot of energy. Mitochondria naturally produce small compounds called oxidants that can damage muscle cells and can cause inflammation. The cells in the body have a natural defence system to protect against oxidants, but when mitochondria age and become less efficient, the amount of oxidants that they produce can increase. These oxidants can damage muscles and the mitochondria themselves. Antioxidants, such as vitamin C, may help protect muscles from the damage caused by oxidants, and may help mitochondria work more efficiently. In this study, the investigators will explore whether vitamin C can help mitochondria work more efficiently, which may improve muscle strength, and help older people to remain mobile and independent for longer.

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy
• Intervention / Treatment: Dietary supplement: Vitamin C; Dietary supplement: Placebo

Detailed Description

The VICS study is a 16-week randomised, double-blind, placebo-controlled two-arm crossover pilot study conducted between the Norfolk and Norwich University Hospital (NNUH) and the Quadram Institute Clinical Research Facility (QI CRF) in Norwich, UK. Investigators are seeking women over the age of 65 years with low habitual fruit and vegetable consumption to determine whether vitamin C supplementation affects mitochondrial function, compared to a matched placebo. Participants will attend 3 clinical visits where investigators will assess skeletal muscle mitochondrial function and membrane turnover using 31-phosphorous magnetic resonance spectroscopy (31P MRS). Investigators will assess muscle strength (hand grip strength and knee extension strength) measured using handheld dynamometers, and physical function measured using the short physical performance battery (SPPB). Investigators will monitor blood levels of vitamin C and inflammatory markers, specifically high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α), and the collagen markers procollagen type-1 N-terminal propeptide (P1NP) and collagen type-1 cross-linked C telopeptide (CTX). Participants will consume one oral capsule daily (containing either 500mg vitamin C or a matched placebo) for the first 6-week intervention period, then, after a 4-week washout phase, participants will crossover and consume the other capsule daily for the second 6-week intervention period. Participants will be asked to complete a food frequency (dietary) questionnaire and physical activity questionnaire at each visit to monitor their physical activity levels and fruit and vegetable consumption.

• Study Type: Interventional
• Enrollment (Estimated): 16
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jamie Scott; Phone Number: 01603591074; Email: J.Scott2@uea.ac.uk
• Study Contact Backup: Name: Professor Ailsa Welch; Email: A.Welch@uea.ac.uk

Study Locations

• United Kingdom
  • Norfolk
    • Norwich, Norfolk, United Kingdom, NR4 7TJ
      • University of East Anglia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Female, aged 65 years or over
• Non-smoker (or ex-smoker for at least 1 year).
• Engages in less than 20 minutes of structured physical activity per week, including cycling.
• Able to provide informed consent.
• Able to understand basic instructions in English.
• Willing to take daily vitamin C or placebo capsules.

Exclusion Criteria:

• Consumes more than 3 fruits and vegetables per day, including fruit and vegetable juices.
• Consumes vitamin C containing supplements, polyphenols, or other antioxidants (e.g. resveratrol or coenzyme q10).
• Regularly takes anti-inflammatory drugs.
• Alcohol intake >14 units/week.
• Chronic clinical diseases (e.g., coronary artery/peripheral artery/cerebrovascular diseases, diabetes, chronic kidney disease requiring dialysis, diagnosed low renal function, neurological disorders or diseases that may affect motor/cognitive functions), except hypertension and hyperlipidaemia.
• History of kidney stones within the preceding 12 months.
• Contraindications for undergoing the MRI and exercise study procedures (e.g. major surgery, bilateral hip or knee replacement, non-MRI-compatible pacemaker or metal implants).
• Parallel participation in another research project that involves an intervention.
• Relation to, or co-habitation with, a member of the study team.
• Those who are part of the line manager/supervisory structure of the Chief Investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Vitamin C, then Placebo; Participants will first consume one 500mg vitamin C capsule daily for 6 weeks. After a 4-week washout period, participants will crossover and consume one placebo capsule daily for 6 weeks.	Dietary supplement: Vitamin C; Vitamin C 500mg hydroxypropyl methylcellulose (HPMC) capsules (Solgar UK).; Dietary supplement: Placebo; Vitamin C-matched placebo capsule. Placebo capsules manufactured using hydroxypropyl methylcellulose (HPMC) capsules and microcrystalline cellulose (MCC).
Experimental: Placebo, then Vitamin C; Participants will first consume one placebo capsule daily for 6 weeks. After a 4-week washout period, participants will crossover and consume one 500mg vitamin C capsule daily for 6 weeks.	Dietary supplement: Vitamin C; Vitamin C 500mg hydroxypropyl methylcellulose (HPMC) capsules (Solgar UK).; Dietary supplement: Placebo; Vitamin C-matched placebo capsule. Placebo capsules manufactured using hydroxypropyl methylcellulose (HPMC) capsules and microcrystalline cellulose (MCC).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in skeletal muscle mitochondrial function between vitamin C and placebo groups.	Comparison of skeletal muscle mitochondrial oxidative capacity (estimated from 31P MRS measured phosphocreatine recovery half-time) following 6 weeks of vitamin C supplementation or 6 weeks of placebo.	Week: 6 and 16

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in skeletal muscle phosphomonoester to phosphodiester ratio (PME/PDE) between vitamin C and placebo groups.	Skeletal muscle phosphomonoester (PME) and phosphodiester (PDE) concentrations can be measured using 31P MRS, and reflect cell membrane synthesis and breakdown respectively. The signal amplitudes (in arbitrary units) of these two species will be combined to report the (unitless) PME/PDE ratio, which reflects cell membrane turnover and may be related to oxidative stress. Comparison of PME/PDE ratio following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in knee extension strength between vitamin C and placebo groups.	Comparison of knee extension strength following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in hand grip strength between vitamin C and placebo groups.	Comparison of hand grip strength following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in Short Physical Performance Battery (SPPB) score between vitamin C and placebo groups.	The Short Physical Performance Battery (SPPB) assesses three components of physical performance: standing balance, gait speed and chair stands. Each of the three components is scored from 0 (worst possible performance) to 4 (best possible performance). Scores from each of the three components are then summed to provide an overall SPPB score ranging from 0 (worst performance) to 12 (best performance). Comparison of SPPB score following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in plasma vitamin C between vitamin C and placebo groups.	Comparison of plasma vitamin C following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in serum hs-CRP between vitamin C and placebo groups.	Comparison of serum hs-CRP following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in serum IL-6 between vitamin C and placebo groups.	Comparison of serum IL-6 following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in serum TNF-α between vitamin C and placebo groups.	Comparison of serum TNF-α following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in plasma P1NP between vitamin C and placebo groups.	Comparison of plasma P1NP following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.
Difference in plasma CTX between vitamin C and placebo groups.	Comparison of plasma CTX following 6 weeks of vitamin C or 6 weeks of placebo.	Week: 6 and 16.

Collaborators and Investigators

• Sponsor: University of East Anglia
• Collaborators: The Norfolk and Norwich University Hospitals NHS Foundation Trust; The Quadram Institute Clinical Research Facility
• Investigators: Principal Investigator: Dr Max Yates, Norfolk and Norwich University Hospitals NHS Foundation Trust

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2024
• Primary Completion (Estimated): March 1, 2025
• Study Completion (Estimated): March 1, 2025

Study Registration Dates

• First Submitted: February 5, 2024
• First Submitted That Met QC Criteria: February 13, 2024
• First Posted (Actual): February 16, 2024

Study Record Updates

• Last Update Posted (Actual): February 16, 2024
• Last Update Submitted That Met QC Criteria: February 13, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: muscle strength; physical function; skeletal muscle; vitamin C; mitochondrial function
• Other Study ID Numbers: 321917

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data supporting the findings of this study will be made available by the authors to any qualified researcher upon reasonable request.
• IPD Sharing Time Frame: Data will be made available upon publication of the study results, and will be available for 10 years from the study end date.
• IPD Sharing Access Criteria: Data request must be made by a qualified researcher.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No