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, 36 (6), 278-85

Efficacy of Vitamin C Supplements in Prevention of Cancer: A Meta-Analysis of Randomized Controlled Trials

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Efficacy of Vitamin C Supplements in Prevention of Cancer: A Meta-Analysis of Randomized Controlled Trials

Bobae Lee et al. Korean J Fam Med.

Abstract

Background: Previous randomized controlled trials (RCTs) have reported inconsistent findings regarding the association between vitamin C supplementation and the risk of cancer.

Methods: We performed a meta-analysis of RCTs to investigate the efficacy of vitamin C supplements for prevention of cancer. We searched the PubMed, EMBASE, and Cochrane Library databases in November 2014 using common keywords related to vitamin C supplements and cancer.

Results: Among 785 articles, a total of seven trials were identified, which included 62,619 participants; 31,326 and 31,293 were randomized to vitamin C supplementation and control or placebo groups, respectively, which were included in the final analysis. A fixed-effects meta-analysis of all seven RCTs revealed no significant association between vitamin C supplementation and cancer (relative risk, 1.00; 95% confidence intervals, 0.95-1.05). Similarly, subgroup meta-analysis by dose of vitamin C administered singly or in combination with other supplements, follow-up period, methodological quality, cancer mortality, gender, smoking status, country, and type of cancer also showed no efficacy of vitamin C supplementation for cancer prevention.

Conclusion: This meta-analysis shows that there is no evidence to support the use of vitamin C supplements for prevention of cancer.

Keywords: Ascorbic Acid; Cancer; Meta-Analysis; Randomized Controlled Trials; Vitamin C.

Conflict of interest statement

CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported.

Figures

Figure 1
Figure 1. Flow diagram for identification of relevant studies.
Figure 2
Figure 2. Effect of vitamin C supplement and control on cancer incidence and mortality in randomized controlled trials (n = 7).
Figure 3
Figure 3. Begg's funnel plot and Egger's test for identifying publication bias. RR, relative risk.

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References

    1. Dizdaroglu M, Jaruga P. Mechanisms of free radical-induced damage to DNA. Free Radic Res. 2012;46:382–419. - PubMed
    1. Pitocco D, Zaccardi F, Di Stasio E, Romitelli F, Santini SA, Zuppi C, et al. Oxidative stress, nitric oxide, and diabetes. Rev Diabet Stud. 2010;7:15–25. - PMC - PubMed
    1. Cameron E, Pauling L. The orthomolecular treatment of cancer. I. The role of ascorbic acid in host resistance. Chem Biol Interact. 1974;9:273–283. - PubMed
    1. Cameron E, Campbell A. The orthomolecular treatment of cancer. II. Clinical trial of high-dose ascorbic acid supplements in advanced human cancer. Chem Biol Interact. 1974;9:285–315. - PubMed
    1. Cameron E, Pauling L. Supplemental ascorbate in the supportive treatment of cancer: prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A. 1976;73:3685–3689. - PMC - PubMed
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