Systematic review and meta-analysis of randomised controlled trials testing the effects of vitamin C supplementation on blood lipids

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#antioxidants #ascorbic-acid #ascorbic-acid-deficiency #cardiovascular-agents #cardiovascular-diseases

Systematic review and meta-analysis of randomised controlled trials testing the effects of vitamin C supplementation on blood lipids

Ashor et al., 2016 | Clin Nutr | Meta Analysis

Citation

Ashor Ammar W, Siervo Mario, ... Mathers John C. Systematic review and meta-analysis of randomised controlled trials testing the effects of vitamin C supplementation on blood lipids. Clin Nutr. 2016-Jun;35(3):626-37. doi:10.1016/j.clnu.2015.05.021

Abstract

BACKGROUND & AIMS: Randomised controlled trials (RCTs) in humans revealed contradictory results regarding the effect of vitamin C supplementation on blood lipids. We aimed to conduct a systematic review and meta-analysis of RCTs investigating the effect of vitamin C supplementation on total cholesterol, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C) and triglycerides and to determine whether the effects are modified by the participants' or intervention characteristics. METHODS: Four databases (PubMed, Embase, Scopus and Cochrane Library) were searched from inception until August 2014 for RCTs supplementing adult participants with vitamin C for ≥ 2 weeks and reporting changes in blood lipids. RESULTS: Overall, vitamin C supplementation did not change blood lipids concentration significantly. However, supplementation reduced total cholesterol in younger participants (≤52 years age) (-0.26 mmol/L, 95% CI: -0.45, -0.07) and LDL-C in healthy participants (-0.32 mmol/L, 95% CI: -0.57, -0.07). In diabetics, vitamin C supplementation reduced triglycerides significantly (-0.15 mmol/L, 95% CI: -0.30, -0.002) and increased HDL-C significantly (0.06 mmol/L, 95% CI: 0.02, 0.11). Meta-regression analyses showed the changes in total cholesterol (β: -0.24, CI: -0.36, -0.11) and in triglycerides (β: -0.17, CI: -0.30, -0.05) following vitamin C supplementation were greater in those with higher concentrations of these lipids at baseline. Greater increase in HDL-C was observed in participants with lower baseline plasma concentrations of vitamin C (β: -0.002, CI: -0.003, -0.0001). CONCLUSIONS: Overall, vitamin C supplementation had no significant effect on lipid profile. However, subgroup and sensitivity analyses showed significant reductions in blood lipids following supplementation in sub-populations with dyslipidaemia or low vitamin C status at baseline. PROSPERO Database registration: CRD42014013487, http://www.crd.york.ac.uk/prospero/.

Key Findings

Overall, vitamin C supplementation did not change blood lipids concentration significantly. However, supplementation reduced total cholesterol in younger participants (≤52 years age) (-0.26 mmol/L, 95% CI: -0.45, -0.07) and LDL-C in healthy participants (-0.32 mmol/L, 95% CI: -0.57, -0.07). In diabetics, vitamin C supplementation reduced triglycerides significantly (-0.15 mmol/L, 95% CI: -0.30, -0.002) and increased HDL-C significantly (0.06 mmol/L, 95% CI: 0.02, 0.11). Meta-regression analyses

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population healthy participants
Sample Size See abstract
Age Range See abstract
Condition See abstract

MeSH Terms

  • Antioxidants
  • Ascorbic Acid
  • Ascorbic Acid Deficiency
  • Cardiovascular Agents
  • Cardiovascular Diseases
  • Dyslipidemias
  • Humans
  • Hyperlipidemias
  • Hypolipidemic Agents
  • Oxidative Stress
  • Randomized Controlled Trials as Topic
  • Reproducibility of Results
  • Risk

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: vitamin-c

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09