Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
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.
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.
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Vitamin C then Placebo | Experimental | 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 | Experimental | Participants will receive a placebo tablet upon wake for the first visit, and a 1.5g dose of Ascorbic Acid on the second visit. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Vitamin C | Dietary Supplement | 1.5g Ascorbic Acid |
|
| Measure | Description | Time Frame |
|---|---|---|
| Vascular Endothelial Function | 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. | Approximately three months |
| Oxidative stress | Oxidative stress will be measured as malondialdehyde (MDA) adducts from Ethylenediaminetetraacetic acid (EDTA) plasma. Higher values may indicate increased oxidative stress. | Approximately three months |
| Plasma Vitamin C and Tetrahydrobiopterin | 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. | Approximately three months |
| Measure | Description | Time Frame |
|---|---|---|
| Platelet aggregation | 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. | Approximately three months |
| Plasminogen activator inhibitor -1 |
Not provided
Inclusion Criteria:
Not provided
Not provided
Not provided
Not provided
Not provided
| Name | Affiliation | Role |
|---|---|---|
| Saurabh S Thosar, PhD | Oregon Health and Science University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Oregon Health & Science University | Portland | Oregon | 97239 | United States |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| ID | Term |
|---|---|
| D001205 | Ascorbic Acid |
| ID | Term |
|---|---|
| D013400 | Sugar Acids |
| D000144 | Acids, Acyclic |
| D002264 | Carboxylic Acids |
| D009930 | Organic Chemicals |
Not provided
Not provided
Not provided
Not provided
Not provided
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.
| Placebo | Other | Inactive placebo to mimic 1.5g ascorbic acid. |
|
Plasminogen activator inhibitor-1 (PAI-1) will be measured from plasma as a blood inflammatory marker. Higher values may indicate increased cardiovascular risk. |
| Approximately three months |
| D006880 |
| Hydroxy Acids |
| D002241 | Carbohydrates |