Vitamin D for Cancer Survival Rate
Higher 25(OH)D levels are associated with better colorectal and breast cancer survival in observational cohorts, and VITAL showed a signal for reduced cancer mortality in secondary analyses. However, no trial has established that supplementing vitamin D improves survival. Correcting deficiency is reasonable for bone and immune health — not as cancer therapy.
Overview
Verdict
Observational links between vitamin D sufficiency and cancer outcomes have not translated into proven survival benefit from supplementation.
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- Only to correct deficiency (1,000–4,000 IU/day), in coordination with the oncology team.
- Expected timeframe
- Not applicable for survival endpoints.
Protocol
- form
- Vitamin D3 (cholecalciferol); VITAL used 2,000 IU/day, and the SUNSHINE trial used high-dose D3 alongside chemotherapy
- duration
- VITAL ran 5 years; oncology trials ran through treatment courses
- co factor
- Evidence is insufficient for survival benefit. The VITAL trial of 25,871 adults found vitamin D3 2,000 IU/day did not reduce cancer incidence, but a secondary analysis suggested reduced cancer mortality, particularly after excluding the first two years - a post-hoc finding. Meta-analyses of vitamin D trials similarly hint at reduced cancer mortality without reduced incidence. The SUNSHINE trial in metastatic colorectal cancer found high-dose vitamin D improved progression-free survival in a secondary analysis, but the trial was small and the primary endpoint was not met. None of this is confirmatory.
- titration
- Not applicable for this indication; 4,000 IU/day is the tolerable upper intake level for general use
- starting dose
- Not established as a cancer treatment. Trials used 2,000-4,000 IU/day of vitamin D3
Evidence
Efficacy of vitamin D3 supplementation on cancer mortality: systematic review and individual patient data meta-analysis of randomised controlled trials
Kuznia S, et al
A subgroup analysis revealed that vitamin D3 administered daily, in contrast to bolus supplementation, reduced cancer mortality by 12%.
Association between vitamin D supplementation and mortality: systematic review and meta-analysis
Zhang Y, et al
Vitamin D supplementation reduced the risk of cancer death by 16%.
Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease (VITAL)
Manson JE, Cook NR, Lee IM
Supplementation with vitamin D did not result in a lower incidence of major cardiovascular events than placebo.
Long-Term Effect of Randomization to Calcium and Vitamin D Supplementation on Health in Older Women: Postintervention Follow-up of a Randomized Clinical Trial
Thomson CA, et al
Calcium and vitamin D supplements seemed to reduce cancer mortality and increase CVD mortality after more than 20 years of follow-up.
Safety
Caveats
Never delay or replace oncology treatment. Discuss all supplements with the treating oncologist due to interaction risks.
Less likely to help if
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.