Vitamin C supplementation showed greater effects on systolic blood pressure in hypertensive and diabetic patients: an updated systematic review and meta-analysis of randomised clinical trials

Abstract

Results from randomised controlled trials (RCTs) testing the effect of vitamin C supplementation on blood pressure (BP) have been inconsistent. This systematic review evaluated the effects of vitamin C supplementation on BP and included RCTs testing the effects of vitamin C supplementation alone, on systolic and diastolic BP in adult participants (≥18 years). Random-effect models were conducted to estimate the pooled effects of vitamin C supplementation on BP. A total of 20 studies with 890 participants were included. The median dose of vitamin C was 757.5 mg/d, the median duration was 6 weeks. Vitamin C supplementation was found to reduce systolic BP by −3.0 mmHg (95%CI: −4.7, −1.3 mmHg; p = 0.001). Subgroup analysis showed a more pronounced effect on systolic BP in patients with hypertension (−3.2 mmHg, 95%CI −5.2, −1.2 mmHg, p = 0.002) and diabetes (−4.6 mmHg, 95%CI −8.9, −0.3 mmHg, p = 0.03). Further research needs to evaluate the long-term effect of vitamin C on BP in populations with impaired cardio-metabolic health.

Keywords:

• Vitamin C
• blood pressure
• hypertension

Author contributions

Conceptualisation, M.S.; methodology, M.S.; formal analysis, E.L. and M.S.; investigation, K.K., E.L., M.S.; resources, M.S; writing—original draft preparation, E.L. and K.K.; writing—review and editing, M.S., B.S., I.S, K.T. All authors have read and agreed to the published version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Not applicable.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.