Effect of Antioxidant Vitamin Supplementation on Cardiovascular Outcomes: A Meta-Analysis of Randomized Controlled Trials

Abstract

BackgroundAntioxidant vitamin (vitamin E, beta-carotene, and vitamin C) are widely used for preventing major cardiovascular outcomes. However, the effect of antioxidant vitamin on cardiovascular events remains unclear.Methodology and Principal FindingsWe searched PubMed, EmBase, the Cochrane Central Register of Controlled Trials, and the proceedings of major conferences for relevant literature. Eligible studies were randomized controlled trials that reported on the effects of antioxidant vitamin on cardiovascular outcomes as compared to placebo. Outcomes analyzed were major cardiovascular events, myocardial infarction, stroke, cardiac death, total death, and any possible adverse events. We used the I2 statistic to measure heterogeneity between trials and calculated risk estimates for cardiovascular outcomes with random-effect meta-analysis. Independent extraction was performed by two reviewers and consensus was reached. Of 293 identified studies, we included 15 trials reporting data on 188209 participants. These studies reported 12749 major cardiovascular events, 6699 myocardial infarction, 3749 strokes, 14122 total death, and 5980 cardiac deaths. Overall, antioxidant vitamin supplementation as compared to placebo had no effect on major cardiovascular events (RR, 1.00; 95%CI, 0.96–1.03), myocardial infarction (RR, 0.98; 95%CI, 0.92–1.04), stroke (RR, 0.99; 95%CI, 0.93–1.05), total death (RR, 1.03; 95%CI, 0.98–1.07), cardiac death (RR, 1.02; 95%CI, 0.97–1.07), revascularization (RR, 1.00; 95%CI, 0.95–1.05), total CHD (RR, 0.96; 95%CI, 0.87–1.05), angina (RR, 0.98; 95%CI, 0.90–1.07), and congestive heart failure (RR, 1.07; 95%CI, 0.96 to 1.19).Conclusion/SignificanceAntioxidant vitamin supplementation has no effect on the incidence of major cardiovascular events, myocardial infarction, stroke, total death, and cardiac death.

Association of lipid peroxidation and antioxidant status with metabolic syndrome in Iranian healthy elderly women

“…Based on this finding, some researchers have reported the beneficial effect of antioxidant vitamin supplementation on decreasing CVD risk in MetS patients (15) while others showed no effect (31,32). However, the majority of those studies have not monitored the improvement in antioxidant status with antioxidant therapy.…”

10.5937/racter6-5469 = Analysis of actual practice of acute ischaemic stroke pharmacotherapy in intensive care unit: Case series

“…The administration of vitamin supplements could have been justified only if malnutrition or need of nutritional support were reported in the patient's file as this is also stated in the NICE guidelines used for this study. Meta-analyses have shown that supplementation of vitamins with antioxidant properties (including vitamin C) can neither prevent stroke 9 , nor improve clinical outcomes in the patients with acute ischaemic stroke 10 , although there are studies which have found improvements in biochemical parameters of antioxidant capacity 11,12 . Therefore, routine use of vitamin C or B vitamins in acute ischemic stroke cannot be recommended 10 .…”

Pretreatment with Antioxidants Augments the Acute Arterial Vasoconstriction Caused by Diesel Exhaust Inhalation

“…The epidemiology research using AO supplementation to prevent adverse cardiovascular events has been disappointing, with multiple studies showing no improvement in outcomes (28)(29)(30)(31)(32). The results in human particulate air pollution exposure studies have been more mixed.…”