Key findings from detailed records
Vitamin C is essential for normal collagen synthesis and other functions. In a prevention trial involving 14,641 male physicians aged 50 or older, 500 mg/day for about 8 years did not reduce major cardiovascular events. Correcting deficiency and adding a supplement to an adequately nourished population are different questions.
KNOWLEDGE RECORD
- Category
- Vitamins and minerals
- Last Reviewed
Names and related search termsVitamin C / Vitamin C / Ascorbic acid
Study type: human intervention study.
OUTCOME-SPECIFIC EVIDENCE
Scientific Evidence Profile
Assessment pending
An outcome-specific assessment has not yet been completed. This is not a finding that the ingredient is ineffective. The study records below remain available.
This profile concerns the stated outcome and population, not the ingredient as a whole. It is not a probability of benefit, a safety rating, a product efficacy rating or an indication of product adoption.
How we assess evidenceIngredient Profile
- What is it, and where is it found?
- Vitamin C, or ascorbic acid, is water-soluble. Fruit and vegetables are important sources; storage and cooking can affect their vitamin C content. [1]
Sources for this profile
Compound properties and formulation properties are different. These sources do not establish the efficacy of a finished supplement.
- NIH Office of Dietary Supplements — VitaminC Nutrient identity and food-source reference. Published by NIH Office of Dietary Supplements. Reference synthesis; not an individual clinical trial.
Profile sources checked:
Read the evidence in context
- Evidence: what was measured in the stated population or experimental model.
- Inference: an interpretation connecting findings; its applicability depends on the study conditions.
- Hypothesis: a proposed explanation or effect that remains to be tested.
Why It Matters #
Does supplementing an essential nutrient prevent cardiovascular events? Check the detailed records for study conditions and use the literature map to compare other populations and outcomes.
What Was Studied #
14,641 US male physicians aged 50 or older Physicians’ Health Study II: double-blind factorial randomized trial. Outcomes: Composite of myocardial infarction, stroke and cardiovascular death[1]
What Was Found #
Major cardiovascular events with vitamin C: HR 0.99 (95% CI 0.89–1.11). No significant reduction.[1]
What the Evidence Means #
A population of male physicians. The trial did not directly address deficiency, skin, infection or other questions.[1]
Comparing similar populations, formulations, durations and outcomes helps identify where findings agree and where they differ.
What We Can Learn #
Distinguish a nutrient's essential role from disease prevention through additional supplementation.
What Remains Unknown #
Further questions include reproducibility across populations and formulations, and the long-term balance of benefits and harms. Use the literature map as a starting point for these questions.
LITERATURE MAP / 10 PAPERS
Compare papers by conditions and findings.
A literature map covering different populations, outcomes and formulations. Read alongside detailed records to avoid treating one trial as the conclusion for an entire ingredient.
Selected: 2026-09-21. Bibliographic information checked against Europe PMC / PubMed. Editorial selection considered major papers and a range of populations and questions. This is not a systematic search covering all recent research.
10 RECORDS
A dash marks fields outside the bibliographic record. Use detailed records to compare findings and design records to connect mechanisms.
No papers match. Change the search conditions.
The literature map is an index of research questions and references. Individual assessment of results, doses, funding and COI is limited to the detailed study records. Related reports from the same trial may be included; paper counts are not counts of independent trials.
Explore the research Study Records
Listed doses describe study conditions, not recommended intake.
Vitamins E and C in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial.
PubMed 18997197DOI: 10.1001/jama.2008.600
- Authors
- Sesso HD, Buring JE, Christen WG, Kurth T, Belanger C, MacFadyen J, Bubes V, Manson JE, Glynn RJ, Gaziano JM.
- Journal
- JAMA
- Publication year
- 2008
- Study design
- Physicians’ Health Study II: double-blind factorial randomized trial
- Participants
- 14,641 US male physicians aged 50 or older
- Dose and intervention
- Vitamin C 500 mg/day. Vitamin E was a separate randomized factor.
- Duration
- Mean 8 years
- Outcomes and their role in the study
- Composite of myocardial infarction, stroke and cardiovascular death
- Findings
- Major cardiovascular events with vitamin C: HR 0.99 (95% CI 0.89–1.11). No significant reduction.
- Limitations
- A population of male physicians. The trial did not directly address deficiency, skin, infection or other questions.
- Funding
- Not verified within the scope of this review. This does not mean “no funding” or “no conflicts of interest.”
- Conflict of Interest
- Not verified within the scope of this review. This does not mean “no funding” or “no conflicts of interest.”
- Scope of source review
- Bibliographic information and abstract checked. Full text and detailed funding/COI information have not been verified.
Cite this page
LÍFSVARÐA. Vitamin C: Does supplementing an essential nutrient prevent cardiovascular events? Version 1.1 / Updated 2026-10-24
https://lifsvarda.com/knowledge/vitamin-c/Edited by LÍFSVARÐA (product brand).Editorial policy
Safety and interactions
High supplemental doses can cause diarrhea and abdominal cramps. Kidney disease or a history of stones warrants individualized advice because vitamin C can increase urinary oxalate. Long-term high doses can worsen iron overload in hereditary hemochromatosis.
Sources and updates
- Sesso HD, Buring JE, Christen WG, Kurth T, Belanger C, MacFadyen J, Bubes V, Manson JE, Glynn RJ, Gaziano JM. (2008). Vitamins E and C in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial.Bibliographic information and abstract checked. Full text and detailed funding/COI information have not been verified.
First published: 2026-09-21 / Version 1.1. Updated 2026-09-23: Added a research comparison table and links to design records. Source notes identify the scope of verification when the full paper has not been reviewed. Research summaries and LÍFSVARÐA’s interpretation are distinguished.