Chronotherapeutic Use of Vitamin C to Reduce Morning Cardiovascular Risk
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 10
- Locations
- 2
- Primary Endpoint
- Plasma Vitamin C and Tetrahydrobiopterin
Study Overview
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 Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Supportive Care
- Masking
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description
Vitamin C and Placebo doses will be blinded by the research pharmacy, so that participants and investigators are masked to the identity of the tablet. Data analysis will be blinded to the conditions as well until the completion of the study.
Eligibility Criteria
- Ages
- 40 Years to 60 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
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.
Outcomes
Primary Outcomes
Plasma Vitamin C and Tetrahydrobiopterin
Time Frame: 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
Time Frame: 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
Time Frame: 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 Outcomes
- Platelet aggregation(Approximately three months)
- Plasminogen activator inhibitor -1(Approximately three months)
Investigators
Steven A. Shea
Director, Oregon Institute of Occupational Health Sciences
Oregon Health and Science University