Objective: Vitamin C has been shown to be an effective therapeutic for reducing total serum cholesterol, but epidemiologic studies have determined that low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol are actually better predictive measures of coronary heart disease risk. Therefore, the purpose of this study was to provide a comprehensive meta-analysis of randomized controlled trials to investigate the effect of vitamin C supplementation on LDL and HDL cholesterol as well as triglycerides in patients with hypercholesterolemia.
Methods: Thirteen randomized controlled trials published between 1970 and June 2007 were identified using Medline and a manual search. From the 13 trials, 14 separate group populations with hypercholesterolemia and who were supplemented with at least 500 mg/d of vitamin C for between 3 and 24 weeks were entered into the meta-analysis. This meta-analysis used a random-effects model; and the overall effect sizes were calculated for changes in LDL and HDL cholesterol, as well as triglyceride concentrations.
Results: The pooled estimate of effect for vitamin C supplementation on LDL and HDL cholesterol was -7.9 mg/dL (95% confidence interval [CI], -12.3 to -3.5; P = .000) and 1.1 mg/dL (95% CI, -0.2 to 2.3; not significant), respectively. The pooled estimate of effect for vitamin C supplementation on triglycerides was -20.1 mg/dL (95% CI, -33.3 to -6.8; P < .003).
Conclusion: Supplementation with at least 500 mg/d of vitamin C, for a minimum of 4 weeks, can result in a significant decrease in serum LDL cholesterol and triglyceride concentrations. However, there was a nonsignificant elevation of serum HDL cholesterol.