Vitamin C intake, circulating vitamin C and risk of stroke: a meta-analysis of prospective studies

J Am Heart Assoc. 2013 Nov 27;2(6):e000329. doi: 10.1161/JAHA.113.000329.


Background: Though vitamin C supplementation has shown no observed effects on stroke prevention in several clinical trials, uncertainty remains as to whether long-term, low-dose intake influences the development of stroke among general populations. Furthermore, the association between circulating vitamin C and the risk of stroke is also unclear. For further clarification of these issues, we conducted a meta-analysis of prospective studies.

Methods and results: PubMed and EMBASE databases were searched, and the bibliographies of the retrieved articles were also reviewed to identify eligible studies. Summary relative risk (RRs) with corresponding 95% confidence intervals (CIs) were computed with a random-effects model. The summary RR for the high-versus-low categories was 0.81 (95% CI: 0.74 to 0.90) for dietary vitamin C intake (11 studies), and 0.62 (95% CI: 0.49 to 0.79) for circulating vitamin C (6 studies). The summary RR for each 100 mg/day increment in dietary vitamin C was 0.83 (95% CI: 0.75 to 0.93) (10 studies), and for each 20 μmol/L increment in circulating vitamin C was 0.81 (95% CI: 0.75 to 0.88) (5 studies). Few studies reported results for vitamin C supplements (RR for high-versus-low intake=0.83, 95% CI: 0.62 to 1.10, 3 studies).

Conclusions: This meta-analysis suggests significant inverse relationships between dietary vitamin C intake, circulating vitamin C, and risk of stroke.

Keywords: antioxidants; diet; meta‐analysis; prevention; stroke.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Ascorbic Acid / administration & dosage*
  • Ascorbic Acid / blood
  • Ascorbic Acid Deficiency / blood
  • Ascorbic Acid Deficiency / diagnosis
  • Ascorbic Acid Deficiency / drug therapy*
  • Ascorbic Acid Deficiency / epidemiology
  • Biomarkers / blood
  • Dietary Supplements*
  • Humans
  • Prognosis
  • Prospective Studies
  • Risk Factors
  • Stroke / blood
  • Stroke / diagnosis
  • Stroke / epidemiology
  • Stroke / prevention & control*
  • Time Factors


  • Biomarkers
  • Ascorbic Acid