Vitamin C to Reduce Morning Cardiovascular Risk

Not Applicable

Completed

• Conditions: Cardiovascular Risk Factor
• Interventions: Dietary Supplement: Vitamin C; Other: Placebo

• Registration Number: NCT03290612
• Lead Sponsor: Oregon Health and Science University

Brief Summary

This study will test the efficacy of Vitamin C to counteract morning cardiovascular (CV) risk markers in a randomized, double blind, placebo controlled crossover pilot study. The participants will also perform morning typical behaviors such as arousal from sleep, change in posture (getting out of bed) and mild intensity physical activity; identical to the stressors encountered in everyday life. Primary dependent variables are markers of cardiovascular risk including vascular endothelial function and oxidative stress.

Detailed Description

The investigators plan to test the efficacy of Vitamin C to counteract morning cardiovascular (CV) risk markers in a randomized, double blind, placebo controlled crossover pilot study. The participants will also perform morning typical behaviors such as arousal from sleep, change in posture (getting out of bed) and mild intensity physical activity; identical to the stressors encountered in everyday life. This pilot study is in healthy middle aged adults without a history of CV disease.

Participants will spend two nights in an inpatient hospital suite at Hatfield Research Center. Upon awakening in the morning, they will either ingest Vitamin C or placebo in a randomized order. This will be followed by moderate intensity exercise, recovery, and discharge.

Study Timeline

• Study First Submitted: 2017-09-18
• Study First Submitted QC: 2017-09-19
• Study First Posted: 2017-09-25
• Study Start: 2018-02-13
• Primary Completion: 2022-03-01
• Study Completion: 2022-03-01
• Status Verified: 2023-03
• Last Update Submitted: 2023-03-21
• Last Update Posted: 2023-03-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 10

Inclusion Criteria

• Healthy participants
• Normal weight or overweight but not obese (18.5<BMI<33 kg/m2)

Exclusion Criteria

• History of smoking/tobacco use
• Current prescription/non-prescription medications or drugs of abuse
• Acute, chronic, or debilitating medical conditions
• History of working irregular day and night hours, regular night work, or rotating shift work for the six months prior to the study.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Vitamin C then Placebo	Vitamin C	Participants will receive a 1.5g dose of Ascorbic Acid upon wake for the first visit, and a placebo tablet on the second visit.
Vitamin C then Placebo	Placebo	Participants will receive a 1.5g dose of Ascorbic Acid upon wake for the first visit, and a placebo tablet on the second visit.
Placebo then Vitamin C	Vitamin C	Participants will receive a placebo tablet upon wake for the first visit, and a 1.5g dose of Ascorbic Acid on the second visit.
Placebo then Vitamin C	Placebo	Participants will receive a placebo tablet upon wake for the first visit, and a 1.5g dose of Ascorbic Acid on the second visit.

Primary Outcome Measures

Name	Time	Method
Plasma Vitamin C and Tetrahydrobiopterin	Approximately three months	We will measure Vitamin C levels in the plasma to ensure that the levels are increased after supplementation, and to control for baseline levels. We will measure tetrahydrobiopterin (BH4) from plasma to test if levels are increased upon administration of Vitamin C.
Vascular Endothelial Function	Approximately three months	Vascular endothelial function will be measured as flow-mediated dilation (FMD). We will measure brachial artery FMD immediately upon awakening in a constant posture following an overnight fast using the standard guidelines and protocol.
Oxidative stress	Approximately three months	Oxidative stress will be measured as malondialdehyde (MDA) adducts from Ethylenediaminetetraacetic acid (EDTA) plasma. Higher values may indicate increased oxidative stress.

Secondary Outcome Measures

Name	Time	Method
Platelet aggregation	Approximately three months	Platelet aggregation will be measured using Chronolog 560 VS Platelet aggregometer as an indicator of how well blood clots or clumps together. Higher values may indicate increased cardiovascular risk.
Plasminogen activator inhibitor -1	Approximately three months	Plasminogen activator inhibitor-1 (PAI-1) will be measured from plasma as a blood inflammatory marker. Higher values may indicate increased cardiovascular risk.

Trial Locations

Locations (1)

Oregon Health & Science University; 🇺🇸 Portland, Oregon, United States