Vitamin C for Endothelial Function
Vitamin C improves endothelial function in people with deficiency, diabetes or smoking history, but adds little for healthy, replete adults.
Overview
Verdict
Context-dependent. Correct a deficiency, but do not expect vascular benefit if your status is already good.
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- 500 mg daily, ideally from diet first
- Expected timeframe
- 4-8 weeks
Protocol
- form
- Ascorbic acid, or buffered ascorbate if stomach upset occurs; divided dosing improves absorption
- duration
- 4-8 weeks
- co factor
- Take with food in divided doses. Evidence is mixed. This is one of the better-documented vascular effects of vitamin C: a meta-analysis by Ashor and colleagues of 44 trials found vitamin C supplementation improved flow-mediated dilation, with effects concentrated in people with existing endothelial dysfunction - diabetes, hypertension, heart failure, smokers - and doses above 500 mg/day. The mechanism is scavenging superoxide, which otherwise destroys nitric oxide, and recycling tetrahydrobiopterin, the cofactor for nitric oxide synthase. In healthy people with normal endothelial function, effects are minimal, and no outcome trial has shown reduced cardiovascular events.
- titration
- Up to 2,000 mg/day, the tolerable upper intake level for adults
- starting dose
- 500 mg twice daily with food
Evidence
What the studies say
Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia: an effect reversible with vitamin C therapy
Chambers JC, McGregor A, Jean-Marie J
Oral methionine loading raised homocysteine and acutely impaired flow-mediated endothelial function in healthy men.
Antioxidant vitamin C improves endothelial function in obstructive sleep apnea
Grebe M
The reduced endothelial-dependent vasodilation in untreated patients with OSA acutely improves by the free radical scavenger vitamin C.
Safety
Caveats
Doses above 1 g may cause GI upset and increase oxalate kidney stone risk in susceptible people.
Less likely to help if
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.