Korean J Fam Med.  2015 Nov;36(6):278-285. 10.4082/kjfm.2015.36.6.278.

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

• Lee B
• Oh SW
• Myung SK

• KMID: 2235217
• DOI: http://doi.org/10.4082/kjfm.2015.36.6.278

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.

Keyword

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

MeSH Terms

Ascorbic Acid*
Follow-Up Studies
Mortality
Smoke
Smoking
Vitamins*
Ascorbic Acid
Smoke
Vitamins