Published on July 29, 2025
New research consolidates vitamin D’s critical role in reducing cancer risk and improving treatment outcomes across multiple cancer types
Key Points
- Vitamin D and cancer prevention: Robust evidence links optimal vitamin D status with significantly lower risks of breast, colorectal, prostate, lung, melanoma, and at least a dozen other cancers.
- Impact on treatment outcomes: Adequate vitamin D levels are associated with enhanced survival rates, reduced tumor progression, and lower metastasis incidence.
- Underlying mechanisms: Vitamin D exerts anticancer effects by regulating immune function, inhibiting malignant cell proliferation, reducing inflammation, and promoting DNA repair.
- GrassrootsHealth’s legacy: Founded by breast cancer survivor Carole Baggerly, GrassrootsHealth leads a global movement advocating for vitamin D awareness, testing, and personalized supplementation to empower cancer prevention.
It was our founder Carole Baggerly’s breast cancer diagnosis, treatment, and recovery story that fueled the founding of GrassrootsHealth and our mission to empower individuals through education, research, and vitamin D testing. Due to her motivation to share the importance of vitamin D in cancer prevention using innovative community research models and advocacy, GrassrootsHealth has significantly advanced public understanding of vitamin D’s role in cancer prevention and survival worldwide.
Learn more about the story of our founding here.
While vitamin D’s role in bone health is well-established, emerging science reveals its far-reaching influence in oncology. A newly published 2025 comprehensive review in Nutrients by Dr. Sunil Wimalawansa, a member of the GrassrootsHealth scientist panel, synthesizes findings from extensive epidemiological studies, randomized controlled trials, and mechanistic research. A summary of his findings are presented below.
Vitamin D and Cancer Prevention: Substantial Evidence Across Key Cancers
The review affirms consistent, statistically significant associations between higher circulating 25(OH)D concentrations and reduced cancer incidence, including:
Breast cancer: Vitamin D promotes cellular differentiation, inhibits tumor growth pathways, and modulates hormone-related cancer mechanisms.
Colorectal cancer: By supporting gut mucosal immunity and attenuating chronic inflammation, vitamin D helps prevent tumorigenesis.
Prostate cancer: Elevated vitamin D levels correlate with slower disease progression and improved patient prognoses.
Lung and melanoma cancers: Immune-enhancing and anti-proliferative properties of vitamin D contribute to lower incidence and improved outcomes.
The findings are summarized in the table below, courtesy of vitamindwiki.com.
Vitamin D Enhances Cancer Prognosis and Treatment Efficacy
Beyond prevention, optimal vitamin D status supports better clinical outcomes:
- Patients with sufficient vitamin D generally show greater responsiveness to conventional treatments, including chemotherapy and immunotherapy.
- Vitamin D facilitates anti-tumor immune responses, bolstering the body’s natural defenses against malignant cells.
- It may inhibit metastatic processes by altering cancer cell adhesion, migration, and the tumor microenvironment.
Mechanistic Insights: How Vitamin D Works Against Cancer
Vitamin D’s anticancer actions operate via multiple molecular pathways:
- Regulating gene expression to induce cancer cell cycle arrest and apoptosis, limiting tumor growth.
- Suppressing pro-inflammatory signaling cascades, thereby reducing a key driver of carcinogenesis.
- Enhancing DNA repair capacity and reducing oxidative DNA damage, protecting genomic integrity.
- Modulating innate and adaptive immune responses to promote tumor surveillance and clearance.
What This Means for You: Proactive Steps Toward Cancer Prevention & Survival
Maintaining optimal vitamin D status represents a cost-effective, accessible strategy for reducing cancer risk and supporting therapeutic outcomes. Regular serum 25(OH)D testing is essential to guide personalized vitamin D optimization and maximize benefits.
Take control of your health—test your vitamin D levels today and support your body’s natural defenses against cancer.
About Dr. Sunil Wimalawansa, M.D., Ph.D.
Dr. Sunil Wimalawansa, M.D., Ph.D., is a renowned physician, scientist, and expert in the field of endocrinology, particularly known for his work in the areas of vitamin D and its clinical applications. He holds multiple academic positions and is recognized for his extensive research on the role of vitamin D in health and disease prevention. Dr. Wimalawansa has contributed to numerous scientific publications, exploring the therapeutic potential of vitamin D in various medical conditions, including osteoporosis, cardiovascular disease, and diabetes. His work emphasizes the importance of optimal vitamin D levels for overall health and wellness, and he has been a vocal advocate for broader public health initiatives regarding vitamin D deficiency. In addition to his clinical and research expertise, Dr. Wimalawansa is also involved in education, speaking at international conferences and authoring books on the subject of vitamin D and its impact on human health.
Measure Your Levels Today!
Check your vitamin D, CRP, omega-3s and 6s, magnesium, and other important markers today as part of the vitamin D*action project.
Measure your:
- Vitamin D
- Magnesium PLUS Elements (including zinc, copper, selenium, mercury, cadmium and lead)
- Omega-3 Fatty Acids
- hsCRP (for Inflammation)
- HbA1c (for Blood Sugar)
- and more
Did you know that each of the above can be measured at home using a simple blood spot test? As part of our ongoing research project, you can order your home blood spot test kit to get your levels, followed by education and steps to take to help you reach your optimal target levels. Start by enrolling and ordering your kit to measure each of the above important markers, and make sure you are getting enough of each to support better health and wellbeing!
Start Here to Measure Your Levels
How Can You Use this Information for YOUR Health?
Having and maintaining healthy vitamin D and other nutrient levels can help improve your health now and for your future. Measuring is the only way to make sure you are getting enough!
STEP 1 Order your at-home blood spot test kit to measure vitamin D and other nutrients of concern to you, such as omega-3s, magnesium, essential and toxic elements (zinc, copper, selenium, lead, cadmium, mercury); include hsCRP as a marker of inflammation or HbA1c for blood sugar health
STEP 2 Answer the online questionnaire as part of the GrassrootsHealth study
STEP 3 Using our educational materials and tools (such as our dose calculators), assess your results to determine if you are in your desired target range or if actions should be taken to get there
STEP 4 After 3-6 months of implementing your changes, re-test to see if you have achieved your target level(s)
