Vitamin C supplementation improves blood lipids in patients with dyslipidemia or diabetes, meta-analysis shows
- Meta-analysis of 40 randomized, controlled trials with significant heterogeneity
- No overall significant effect of vitamin C supplementation on blood lipid levels
- Subgroup analyses shows significant effects in people with diabetes and others
- Effect is greater when baseline cholesterol and triglyceride levels are higher
This meta-analysis was designed to investigate the effect of vitamin C supplementation on blood cholesterol and triglyceride levels and the effect, if any, of participant or intervention characteristics.
All randomized, controlled trials published in the literature up to until August 2014 with adults supplementing with vitamin C for 2 weeks or longer that reported changes in blood lipids were eligible. A total of 40 clinical trials met the inclusion criteria with a significant degree of heterogeneity.
Overall, vitamin C supplementation had no significant effect on blood lipid levels. However, subgroup and sensitivity analyses showed supplementation significantly (P<.01) reduced total cholesterol in younger subjects (52 years of age or younger) by an average of 0.26 mmol/L (10 mg/dl). Supplementation also significantly (P<.05) reduced LDL-C in healthy subjects by 0.32 mmol/L (12 mg/dl), on average.
In subjects with diabetes, vitamin C supplementation significantly (P<.05) reduced triglycerides by 0.15 mmol/L (13 mg/dl), on average, and significantly (P<.05) increased HDL-cholesterol by 0.06 mmol/L (2 mg/dl), on average.
Meta-regression analyses showed reductions in blood levels of total cholesterol and triglycerides were significantly (P <.05) better in subjects with higher baseline levels. Subjects with lower blood levels of vitamin C at baseline showed a trend (P=.08) toward greater increases in HDL-cholesterol.
These findings suggest vitamin C supplementation offers clinical value in the treatment of cardiovascular disease, especially in patients with dyslipidemia.