Vitamin D for Cancer

Vitamin D for Cancer: What It Is and How It May Help

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Nancy Hepp, MS

past Lead Researcher

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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher and writer for CancerChoices and also served as the first program manager. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS past Lead Researcher

Reviewer

Laura Pole, MSN, RN, OCNS

Senior Clinical Consultant

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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, MSN, RN, OCNS Senior Clinical Consultant

Last update: May 4, 2026

Vitamin D for cancer: what you need to know

• Vitamin D is a hormone that is created by the body with sun exposure; it can also be taken as a supplement and is found naturally in some foods.
• Optimal vitamin D blood levels are linked to better survival, better body terrain factors linked to improved cancer outcomes, and lower risk of cancer.
• Optimal blood levels may also help manage some side effects and symptoms common during cancer treatment.
• Caution with dosing is essential: blood levels of vitamin D above the optimal range may increase risk of certain cancers, and toxicity and overdose are possible when taking high doses of supplements. 
• Chemotherapy may affect vitamin D levels, talk with your doctor about monitoring your levels while in treatment.
• This is not a standalone treatment for cancer; it is a complementary therapy used alongside standard medical care to support treatment and/or well-being.

What is vitamin D?

Vitamin D is a hormone that is created by the body with ultraviolet B (UVB) exposure from the sun. It can also be taken as a supplement and is found naturally in some foods. 

Although definitions of deficiency vary, blood levels below 20 ng/mL are generally considered deficient in vitamin D with regard to cancer risk and outcomes. Optimal vitamin D blood levels are linked to better survival, better conditions—body terrain factors—that are linked to better cancer outcomes, and lower risk of cancer. Optimal levels are also linked to fewer symptoms or less severe symptoms of some side effects common during cancer treatment. Vitamin D supplementation among people who have low blood levels shows benefits.

Testing matters

Some research has found that vitamin D in the body reaches an optimum level regarding cancer risk starting at 20 ng/mL (50 nmol/L) and may have an upper limit below 40 ng/mL (100 nmol/L). Higher levels of vitamin D are not always better and may even carry health risks. An optimal blood level is a better indicator of health benefits than your daily or weekly intake of supplements.

• Note that Vitamin D is measured on two scales: ng/ml and nmol/L. Your doctor can explain which scale is used at your clinic.
• Vitamin D shows up on blood work as 25(OH)D.

It is important to monitor vitamin D levels with a healthcare professional. 

Safety

• Supervision by a medical professional is highly recommended.
• Individuals with calcium metabolism disorders, gastrointestinal disease, kidney disease, heart disease, or liver disease should consult a physician before using vitamin D supplements.
• Vitamin D toxicity and overdose are possible when taking high doses of supplements.
• Increased risk of some types of cancer with blood levels higher than 40 ng/mL (100 nmol/L)
• Known interactions, consult with your healthcare provider before adding to your regimen.

See full safety details, side effects & drug interactions →

How vitamin D may help people with cancer

Strength of evidence rating

We rate the strength of the evidence with 0=no evidence, 1=weak evidence, 2=modest evidence, and 3=good evidence. Read more about our method in detail here ›

Optimizing your body terrain

Research suggests that vitamin D plays a meaningful role in several aspects of body terrain relevant to cancer risk and progression. Low vitamin D levels are associated with obesity,³³Ganji V, Tangpricha V, Zhang X. Serum vitamin D concentration ≥75 nmol/L is related to decreased cardiometabolic and inflammatory biomarkers, metabolic syndrome, and diabetes; and increased cardiorespiratory fitness in US adults. Nutrients. 2020 Mar 10;12(3):730; Shanmugalingam T, Crawley D et al. Obesity and cancer: the role of vitamin D. BMC Cancer. 2014 Sep 25;14:712; Bellia A, Garcovich C et al. Serum 25-hydroxyvitamin D levels are inversely associated with systemic inflammation in severe obese subjects. Internal and Emergency Medicine. 2013 Feb;8(1):33-40; Esteghamati A, Aryan Z, Esteghamati A, Nakhjavani M. Differences in vitamin D concentration between metabolically healthy and unhealthy obese adults: associations with inflammatory and cardiometabolic markers in 4391 subjects. Diabetes & Metabolism. 2014 Nov;40(5):347-55; Xu J, Yuan X et al. Association of circulating 25-hydroxyvitamin D levels with colorectal cancer: an updated meta-analysis. Journal of Nutritional Science and Vitaminology (Tokyo). 2018;64(6):432-444. and people with higher vitamin D levels tend to show better blood sugar control and lower risk of insulin resistance³⁴Ganji V, Tangpricha V, Zhang X. Serum vitamin D concentration ≥75 nmol/L is related to decreased cardiometabolic and inflammatory biomarkers, metabolic syndrome, and diabetes; and increased cardiorespiratory fitness in US adults. Nutrients. 2020 Mar 10;12(3):730; Kostoglou-Athanassiou I, Athanassiou P, Gkountouvas A, Kaldrymides P. Vitamin D and glycemic control in diabetes mellitus type 2. Therapeutic Advances in Endocrinology and Metabolism. 2013 Aug;4(4):122-8; Bellan M, Guzzaloni G et al. Altered glucose metabolism rather than naive type 2 diabetes mellitus (T2DM) is related to vitamin D status in severe obesity. Cardiovascular Diabetology. 2014 Mar 11;13:57; Esteghamati A, Aryan Z, Esteghamati A, Nakhjavani M. Differences in vitamin D concentration between metabolically healthy and unhealthy obese adults: associations with inflammatory and cardiometabolic markers in 4391 subjects. Diabetes & Metabolism. 2014 Nov;40(5):347-55. and type 2 diabetes.³⁵Song Y, Wang L et al. Blood 25-hydroxy vitamin D levels and incident type 2 diabetes: a meta-analysis of prospective studies. Diabetes Care. 2013 May;36(5):1422-8; Pittas AG, Lau J, Hu FB, Dawson-Hughes B. The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. Journal of Clinical Endocrinology and Metabolism. 2007 Jun;92(6):2017-29; Gagnon C, Lu ZX et al. Serum 25-hydroxyvitamin D, calcium intake, and risk of type 2 diabetes after 5 years: results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle study). Diabetes Care. 2011 May;34(5):1133-8. Among people already living with diabetes, vitamin D supplementation has been linked to improved glycemic markers.³⁶Kazemi A, Ryul Shim S et al. Comparison of nutritional supplements for glycemic control in type 2 diabetes: a systematic review and network meta-analysis of randomized trials. Diabetes Research and Clinical Practice. 2022;191:110037; Safarpour P, Daneshi-Maskooni M et al. Vitamin D supplementation improves SIRT1, Irisin, and glucose indices in overweight or obese type 2 diabetic patients: a double-blind randomized placebo-controlled clinical trial. BMC Family Practice. 2020 Feb 7;21(1):26. Women with polycystic ovary syndrome treated with vitamin D have shown better markers of hormone balance.³⁷Fang F, Ni K et al. Effect of vitamin D supplementation on polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Complementary Therapies in Clinical Practice. 2017 Feb;26:53-60.

Evidence consistently shows that sufficient vitamin D levels are associated with lower markers of inflammation,³⁸Yang F, Sun M et al. Associations of C-reactive protein with 25-hydroxyvitamin D in 24 specific diseases: a cross-sectional study from NHANES. Scientific Reports. 2020 Apr 3;10(1):5883; Ganji V, Tangpricha V, Zhang X. Serum vitamin D concentration ≥75 nmol/L is related to decreased cardiometabolic and inflammatory biomarkers, metabolic syndrome, and diabetes; and increased cardiorespiratory fitness in US adults. Nutrients. 2020 Mar 10;12(3):730; Amer M, Qayyum R. Relation between serum 25-hydroxyvitamin D and C-reactive protein in asymptomatic adults (from the continuous National Health and Nutrition Examination Survey 2001 to 2006). American Journal of Cardiology. 2012 Jan 15;109(2):226-30; Ngo DT, Sverdlov AL, McNeil JJ, Horowitz JD. Does vitamin D modulate asymmetric dimethylarginine and C-reactive protein concentrations? The American Journal of Medicine. 2010 Apr;123(4):335-41; Laird E, McNulty H et al. Vitamin D deficiency is associated with inflammation in older Irish adults. Journal of Clinical Endocrinology & Metabolism. 2014 May;99(5):1807-15; Finkelmeier F, Kronenberger B et al. Severe 25-hydroxyvitamin D deficiency identifies a poor prognosis in patients with hepatocellular carcinoma—a prospective cohort study. Alimentary Pharmacology & Therapeutics. 2014 May;39(10):1204-12; Bellia A, Garcovich C et al. Serum 25-hydroxyvitamin D levels are inversely associated with systemic inflammation in severe obese subjects. Internal and Emergency Medicine. 2013 Feb;8(1):33-40. and supplementation has been linked to reduced inflammation³⁹Hu X, Wang W et al. Comparison of nutritional supplements in improving glycolipid metabolism and endocrine function in polycystic ovary syndrome: a systematic review and network meta-analysis. PeerJ. 2023 Nov 13;11:e16410; Gwenzi T, Zhu A et al. Effects of vitamin D supplementation on inflammatory response in patients with cancer and precancerous lesions: systematic review and meta-analysis of randomized trials. Clinical Nutrition. 2023 Jul;42(7):1142-1150; Zhao JF, Li BX, Zhang Q. Vitamin D improves levels of hormonal, oxidative stress and inflammatory parameters in polycystic ovary syndrome: a meta-analysis study. Annals of Palliative Medicine. 2021 Jan;10(1):169-183; Akbari M, Ostadmohammadi V et al. The effects of vitamin D supplementation on biomarkers of inflammation and oxidative stress among women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Hormone and Metabolic Research. 2018 Apr;50(4):271-279; Corrao S, Mallaci Bocchio R et al. Does evidence exist to blunt inflammatory response by nutraceutical supplementation during COVID-19 pandemic? An overview of systematic reviews of vitamin D, vitamin C, melatonin, and zinc. Nutrients. 2021;13(4):1261; Ghavamzadeh S, Mobasseri M, Mahdavi R. The effect of vitamin D supplementation on adiposity, blood glycated hemoglobin, serum leptin and tumor necrosis factor-α in type 2 diabetic patients. International Journal of Preventive Medicine. 2014 Sep;5(9):1091-8; Chen N, Wan Z  et al. Effect of vitamin D supplementation on the level of circulating high-sensitivity C-reactive protein: a meta-analysis of randomized controlled trials. Nutrients. 2014 Jun 10;6(6):2206-16. and oxidative stress⁴⁰Vahedpoor Z, Mahmoodi S et al. Long-term vitamin D supplementation and the effects on recurrence and metabolic status of cervical intraepithelial neoplasia grade 2 or 3: a randomized, double-blind, placebo-controlled trial. Annals of Nutrition and Metabolism. 2018;72(2):151-160; Avelino CMSF, de Araújo RFF. Effects of vitamin D supplementation on oxidative stress biomarkers of Iranian women with polycystic ovary syndrome: a meta-analysis study. Revista Brasileira de Ginecologia e Obstetricia. 2024 Jun 27;46:e-rbgo37; Zhao JF, Li BX, Zhang Q. Vitamin D improves levels of hormonal, oxidative stress and inflammatory parameters in polycystic ovary syndrome: a meta-analysis study. Annals of Palliative Medicine. 2021 Jan;10(1):169-183; Akbari M, Ostadmohammadi V et al. The effects of vitamin D supplementation on biomarkers of inflammation and oxidative stress among women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Hormone and Metabolic Research. 2018 Apr;50(4):271-279. across many studies. Preliminary findings suggest vitamin D may also support more balanced immune function.⁴¹Chadha MK, Fakih M, Muindi J. Effect of 25-hydroxyvitamin D status on serological response to influenza vaccine in prostate cancer patients. Prostate. 2011 Mar 1;71(4):368-72; Khoo AL, Chai LY et al. Regulation of cytokine responses by seasonality of vitamin D status in healthy individuals. Clinical & Experimental Immunology. 2011 Apr;164(1):72-9; Morita M, Okuyama M et al. Vitamin D supplementation regulates postoperative serum levels of PD-L1 in patients with digestive tract cancer and improves survivals in the highest quintile of PD-L1: a post hoc analysis of the AMATERASU randomized controlled trial. Nutrients. 2021 Jun 9;13(6):1987. In colorectal cancer, one small study found that vitamin D supplementation was associated with lower levels of a pro-inflammatory gut bacterium linked to poorer outcomes.⁴²Bellerba F, Serrano D et al. Colorectal cancer, vitamin D and microbiota: a double-blind phase II randomized trial (ColoViD) in colorectal cancer patients. Neoplasia. 2022 Dec;34:100842.

Reducing cancer risk or recurrence

People with low vitamin D levels have shown a higher risk of cancer as a whole across many studies.⁴³Arayici ME, Basbinar Y, Ellidokuz H. Vitamin D intake, serum 25-hydroxyvitamin-D (25(OH)D) levels, and cancer risk: a comprehensive meta-meta-analysis including meta-analyses of randomized controlled trials and observational epidemiological studies. Nutrients. 2023 Jun 12;15(12):2722. Studies observing people without cancer over time found that vitamin D sufficiency was correlated with lower cancer mortality.⁴⁴Arayici ME, Basbinar Y, Ellidokuz H. Vitamin D intake, serum 25-hydroxyvitamin-D (25(OH)D) levels, and cancer risk: a comprehensive meta-meta-analysis including meta-analyses of randomized controlled trials and observational epidemiological studies. Nutrients. 2023 Jun 12;15(12):2722; Zhang Y, Fang F et al. Association between vitamin D supplementation and mortality: systematic review and meta-analysis. British Medical Journal. 2019 Aug 12;366:l4673; Keum N, Lee DH, Greenwood DC, Manson JE, Giovannucci E. Vitamin D supplementation and total cancer incidence and mortality: a meta-analysis of randomized controlled trials. Annals of Oncology. 2019 May 1;30(5):733-743; Brenner H, Jansen L, Saum KU, Holleczek B, Schöttker B. Vitamin D supplementation trials aimed at reducing mortality have much higher power when focusing on people with low serum 25-hydroxyvitamin D concentrations. Journal of Nutrition. 2017 Jul;147(7):1325-1333; Bjelakovic G, Gluud LL et al. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database of Systematic Reviews. 2014 Jan 10;(1):CD007470. 

Some evidence across many studies suggests that people with low vitamin D levels have higher risk of these cancers: advanced (metastatic) cancer⁴⁵Chandler PD, Chen WY et al. Effect of vitamin D₃ supplements on development of advanced cancer: a secondary analysis of the VITAL randomized clinical trial. Journal of the American Medical Association Network Open. 2020 Nov 2;3(11):e2025850. and cancers of the bladder,⁴⁶Zhao Y, Chen C et al. Comparative efficacy of vitamin D status in reducing the risk of bladder cancer: a systematic review and network meta-analysis. Nutrition. 2016 May;32(5):515-23; Zhang H, Zhang H et al. Vitamin D deficiency and increased risk of bladder carcinoma: a meta-analysis. Cell Physiology and Biochemistry. 2015;37(5):1686-92; Chen F, Li Q, Yu Y, Yang W, Shi F, Qu Y. Association of vitamin C, vitamin D, vitamin E and risk of bladder cancer: a dose-response meta-analysis. Scientific Reports. 2015 Apr 23;5:9599; Liao Y, Huang JL, Qiu MX, Ma ZW. Impact of serum vitamin D level on risk of bladder cancer: a systemic review and meta-analysis. Tumour Biology. 2015 Mar;36(3):1567-72. breast,⁴⁷Torres A, Cameselle C, Otero P, Simal-Gandara J. The impact of vitamin D and its dietary supplementation in breast cancer prevention: an integrative review. Nutrients. 2024 Feb 20;16(5):573; Voutsadakis IA. Vitamin D baseline levels at diagnosis of breast cancer: a systematic review and meta-analysis. Hematology/Oncology and Stem Cell Therapy. 2021 Mar;14(1):16-26; Song D, Deng Y et al. Vitamin D intake, blood vitamin D levels, and the risk of breast cancer: a dose-response meta-analysis of observational studies. Aging (Albany NY). 2019 Dec 28;11(24):12708-12732; Hossain S, Beydoun MA et al. Vitamin D and breast cancer: a systematic review and meta-analysis of observational studies. Clinical Nutrition ESPEN. 2019 Apr;30:170-184; Estébanez N, Gómez-Acebo I, Palazuelos C, Llorca J, Dierssen-Sotos T. Vitamin D exposure and Risk of Breast Cancer: a meta-analysis. Scientific Reports. 2018 Jun 13;8(1):9039; Kim Y, Je Y. Vitamin D intake, blood 25(OH)D levels, and breast cancer risk or mortality: a meta-analysis. British Journal of Cancer. 2014 May 27;110(11):2772-84. colon/rectum,⁴⁸Hernández-Alonso P, Boughanem H et al. Circulating vitamin D levels and colorectal cancer risk: a meta-analysis and systematic review of case-control and prospective cohort studies. Critical Reviews in Food Science and Nutrition. 2023;63(1):1-17; Arayici ME, Basbinar Y, Ellidokuz H. Vitamin D intake, serum 25-hydroxyvitamin-D (25(OH)D) levels, and cancer risk: a comprehensive meta-meta-analysis including meta-analyses of randomized controlled trials and observational epidemiological studies. Nutrients. 2023 Jun 12;15(12):2722; Huang D, Lei S et al. Additively protective effects of vitamin D and calcium against colorectal adenoma incidence, malignant transformation and progression: a systematic review and meta-analysis. Clinical Nutrition. 2020 Aug;39(8):2525-2538; McCullough ML, Zoltick ES et al. Circulating vitamin D and colorectal cancer risk: an international pooling project of 17 cohorts. JNCI: Journal of the National Cancer Institute. 2019 Feb 1;111(2):158-169; Garland CF, Gorham ED. Dose-response of serum 25-hydroxyvitamin D in association with risk of colorectal cancer: a meta-analysis. Journal of Steroid Biochemistry and Molecular Biology. 2017 Apr;168:1-8; Ma Y, Zhang P et al. Association between vitamin D and risk of colorectal cancer: a systematic review of prospective studies. Journal of Clinical Oncology. 2011 Oct 1;29(28):3775-82; Zhang L, Zou H et al. Association between blood circulating vitamin D and colorectal cancer risk in Asian countries: a systematic review and dose-response meta-analysis. British Medical Journal Open. 2019 Dec 23;9(12):e030513; Touvier M, Chan DS et al. Meta-analyses of vitamin D intake, 25-hydroxyvitamin D status, vitamin D receptor polymorphisms, and colorectal cancer risk. Cancer Epidemiology, Biomarkers & Prevention. 2011 May;20(5):1003-16; Choi YJ, Kim YH, Cho CH, Kim SH, Lee JE. Circulating levels of vitamin D and colorectal adenoma: a case-control study and a meta-analysis. World Journal of Gastroenterology. 2015 Aug 7;21(29):8868-77. liver,⁴⁹Yi Z, Wang L, Tu X. Effect of vitamin D deficiency on liver cancer risk: a systematic review and meta-analysis. Asian Pacific Journal of Cancer Prevention. 2021 Apr 1;22(4):991-997; Guo XF, Zhao T, Han JM, Li S, Li D. Vitamin D and liver cancer risk: a meta-analysis of prospective studies. Asia Pacific Journal of Clinical Nutrition. 2020;29(1):175-182; Zhang Y, Jiang X et al. Serum vitamin D levels and risk of liver cancer: a systematic review and dose-response meta-analysis of cohort studies. Nutrition and Cancer. 2021;73(8):1-9. head, neck, or mouth,⁵⁰Patini R, Favetti Giaquinto E et al. Malnutrition as a risk factor in the development of oral cancer: a systematic literature review and meta-analyses. Nutrients. 2024 Jan 26;16(3):360; Pu Y, Zhu G et al. Association between vitamin D exposure and head and neck cancer: a systematic review with meta-analysis. Frontiers in Immunology. 2021 Feb 23;12:627226. kidney,⁵¹Wu J, Yang N, Yuan M. Dietary and circulating vitamin D and risk of renal cell carcinoma: a meta-analysis of observational studies. International Brazilian Journal of Urology. 2021 Jul-Aug;47(4):733-744. lung,⁵²Sun K, Zuo M et al. Anti-tumor effect of vitamin D combined with calcium on lung cancer: a systematic review and meta-analysis. Nutrition and Cancer. 2021;73(11-12):2633-2642; Feng Q, Zhang H, Dong Z, Zhou Y, Ma J. Circulating 25-hydroxyvitamin D and lung cancer risk and survival: a dose-response meta-analysis of prospective cohort studies. Medicine (Baltimore). 2017 Nov;96(45):e8613; Wei H, Jing H, Wei Q, Wei G, Heng Z. Associations of the risk of lung cancer with serum 25-hydroxyvitamin D level and dietary vitamin D intake: a dose-response PRISMA meta-analysis. Medicine (Baltimore). 2018 Sep;97(37):e12282; Chen GC, Zhang ZL et al. Circulating 25-hydroxyvitamin D and risk of lung cancer: a dose-response meta-analysis. Cancer Causes and Control. 2015 Dec;26(12):1719-28; Zhang L, Wang S, Che X, Li X. Vitamin D and lung cancer risk: a comprehensive review and meta-analysis. Cell Physiology and Biochemistry. 2015;36(1):299-305. skin,⁵³Shellenberger RA, Gowda S, Kurn H, Albright J, Mayo MH. Vitamin D insufficiency and serum levels related to the incidence and stage of cutaneous melanoma: a systematic review and meta-analysis. Melanoma Research. 2023 Aug 1;33(4):265-274; Caini S, Boniol M et al. Vitamin D and melanoma and non-melanoma skin cancer risk and prognosis: a comprehensive review and meta-analysis. European Journal of Cancer. 2014 Oct;50(15):2649-58; Samimi M, Touzé A et al. Vitamin D deficiency is associated with greater tumor size and poorer outcome in Merkel cell carcinoma patients. Journal of the European Academy of Dermatology and Venereology. 2014 Mar;28(3):298-308. ovary,⁵⁴Jung S, Jin S, Je Y. Vitamin D intake, blood 25-hydroxyvitamin D, and risk of ovarian cancer: a meta-analysis of observational studies. Journal of Women’s Health (Larchmont). 2023 May;32(5):561-573; Liao MQ, Gao XP et al. Effects of dairy products, calcium and vitamin D on ovarian cancer risk: a meta-analysis of twenty-nine epidemiological studies. British Journal of Nutrition. 2020 Nov 28;124(10):1001-1012. pancreas (among nonsmokers),⁵⁵Genkinger JM, Wang M et al. Dairy products and pancreatic cancer risk: a pooled analysis of 14 cohort studies. Annals of Oncology. 2014 Jun;25(6):1106-15. prostate,⁵⁶Kristal AR, Till C et al. Plasma vitamin D and prostate cancer risk: results from the Selenium and Vitamin E Cancer Prevention Trial. Cancer Epidemiology, Biomarkers and Prevention. 2014 Aug;23(8):1494-504; Tuohimaa P, Lyakhovich A et al. Vitamin D and prostate cancer. Journal of Steroid Biochemistry and Molecular Biology. 2001 Jan-Mar;76(1-5):125-34; Tuohimaa P, Tenkanen L et al. Both high and low levels of blood vitamin D are associated with a higher prostate cancer risk: a longitudinal, nested case-control study in the Nordic countries. International Journal of Cancer. 2004 Jan 1;108(1):104-8. stomach,⁵⁷Zhao X, Wang J, Zou L. Vitamin D and gastric cancer—a systematic review and meta-analysis. Nutrición Hospitalaria. 2023 Oct 6;40(5):1080-1087; Liu X, Zhou Y, Zou X. Correlation between serum 25-hydroxyvitamin D levels and gastric cancer: a systematic review and meta-analysis. Current Oncology. 2022 Nov 2;29(11):8390-8400. and thyroid.⁵⁸Zhao J, Wang H et al. Vitamin D deficiency as a risk factor for thyroid cancer: A meta-analysis of case-control studies. Nutrition. 2019 Jan;57:5-11; Hu MJ, Zhang Q et al. Association between vitamin D deficiency and risk of thyroid cancer: a case-control study and a meta-analysis. Journal of Endocrinological Investigation. 2018 Oct;41(10):1199-1210. Low vitamin D levels are also linked to polycystic ovary syndrome, a risk factor for endometrial cancer.⁵⁹Bacopoulou F, Kolias E, Efthymiou V, Antonopoulos CN, Charmandari E. Vitamin D predictors in polycystic ovary syndrome: a meta-analysis. European Journal of Clinical Investigation. 2017 Oct;47(10):746-755; Jia XZ, Wang YM et al. Effect of vitamin D on clinical and biochemical parameters in polycystic ovary syndrome women: a meta-analysis. Journal of Obstetrics and Gynaecology Research. 2015 Nov;41(11):1791-802; He C, Lin Z, Robb SW, Ezeamama AE. Serum vitamin D levels and polycystic ovary syndrome: a systematic review and meta-analysis. Nutrients. 2015 Jun 8;7(6):4555-77.

People with low vitamin D levels show higher risk of recurrence of breast cancer,⁶⁰Li C, Li H, Zhong H, Li X. Association of 25-hydroxyvitamin D level with survival outcomes in female breast cancer patients: a meta-analysis. Journal of Steroid Biochemistry and Molecular Biology. 2021 Sep;212:105947; Yao S, Sheng H et al. Clinically sufficient vitamin D levels at breast cancer diagnosis and survival outcomes in a prospective cohort of 3,995 patients after a median follow-up of 10 years. Poster presentation at the ASCO 2021 Annual Meeting. Viewed June 15, 2021; Li M, Chen P et al. Review: the impacts of circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis. Journal of Clinical Endocrinology and Metabolism. 2014 Jul;99(7):2327-36; Rose AA, Elser C, Ennis M, Goodwin PJ. Blood levels of vitamin D and early stage breast cancer prognosis: a systematic review and meta-analysis. Breast Cancer Research and Treatment. 2013 Oct;141(3):331-9. lymphoma,⁶¹Li M, Chen P et al. Review: the impacts of circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis. Journal of Clinical Endocrinology and Metabolism. 2014 Jul;99(7):2327-36. and melanoma.⁶²Johansson H, Spadola G et al. Vitamin D supplementation and disease-free survival in stage ii melanoma: a randomized placebo controlled trial. Nutrients. 2021 Jun 4;13(6):1931; Lipplaa A, Fernandes R et al. 25-hydroxyvitamin D serum levels in patients with high risk resected melanoma treated in an adjuvant bevacizumab trial. British Journal of Cancer. 2018 Oct;119(7):793-800.

People taking vitamin D supplements after a cancer diagnosis showed a lower risk of recurrence of cancers of the esophagus,⁶³Wang L, Wang C, Wang J, Huang X, Cheng Y. Longitudinal, observational study on associations between postoperative nutritional vitamin D supplementation and clinical outcomes in esophageal cancer patients undergoing esophagectomy. Scientific Reports. 2016 Dec 13;6:38962. head and neck,⁶⁴Yokosawa EB, Arthur AE et al. Vitamin D intake and survival and recurrence in head and neck cancer patients. Laryngoscope. 2018 Nov;128(11):E371-E376. plus ER positive (but not ER negative) breast cancer⁶⁵Poole EM, Shu X et al. Postdiagnosis supplement use and breast cancer prognosis in the After Breast Cancer Pooling Project. Breast Cancer Research and Treatment. 2013 Jun;139(2):529-37. and cervical intraepithelial neoplasia.⁶⁶Vahedpoor Z, Mahmoodi S et al. Long-term vitamin D supplementation and the effects on recurrence and metabolic status of cervical intraepithelial neoplasia grade 2 or 3: a randomized, double-blind, placebo-controlled trial. Annals of Nutrition and Metabolism. 2018;72(2):151-160. 

See the full evidence summary ›

Affordability and access

Is a prescription required?

• Not for over-the-counter supplements, but we recommend you consult your oncology team if you are taking or planning on taking vitamin D supplements.
• Some formulations and analogs of vitamin D require a prescription.

Forms of vitamin D

Vitamin D supplements come in two forms, D₂ and D₃. Vitamin D₃ is found mainly in animals, while vitamin D₂ comes from plant-sourced foods. Vitamin D₂ is the most common form in fortified foods, but it’s also less effective at raising your blood serum levels.⁶⁷Vitamin D2 vs. D3: What’s the Difference? Healthline. February 21, 2020. Viewed July 1, 2022. When shopping for supplements, pay attention to whether you’re buying vitamin D₂ or D₃, consistent with whether you want nutrients sourced from animals, how severe your deficiency may be, and what your doctor recommends.

Where to find it

Vitamin D supplements are available without a prescription in retail stores:

• Drug stores
• Supplement stores
• Online supplement distributors

Vitamin D is available in some foods:

• Egg yolks
• Cod liver oil
• Fish oil
• Wild fish such as salmon, sardines, herring, and cod
• Blood sausage
• Some organ meats, such as liver
• Butter
• Mushrooms, including medicinal mushrooms, that have been exposed to sunlight, but as a source of vitamin D₂;⁶⁸Keegan RJ, Lu Z, Bogusz JM, Williams JE, Holick MF. Photobiology of vitamin D in mushrooms and its bioavailability in humans. Dermatoendocrinology. 2013 Jan 1;5(1):165-76; Plotnikoff GA. Anticancer medicinal mushrooms can provide significant vitamin D₂ (ergocalciferol). International Journal of Medicinal Mushrooms. 2005;7(3):471-2. vitamin D₂ is less effective than vitamin D₃, which comes only from animal sources, as noted above
• Some dairy products, orange juice, soy milk, and cereals to which vitamin D has been added⁶⁹Derrer DT. Top foods for calcium and vitamin D. WebMD. July 22, 2020. Viewed June 8, 2022.

See our blog post, Plant-Based Sources of Vitamin D for Cancer ›

Sun exposure

You make vitamin D when your skin is exposed to relatively intense sunlight. The Vitamin D Council advises that fifteen minutes (for a person with light skin) to a couple of hours (for a person with very dark skin) in the summer midday sun in swimwear three times a week is sufficient sun exposure for vitamin D.⁷⁰Barrell A. How to get more vitamin D from the sun. Medical News Today. January 21, 2021. Viewed August 1, 2022; McNeill AM. Wesner E. Sun protection and vitamin D. Skin Cancer Foundation. May 14, 2018. Viewed August 1, 2022. Further sun exposure does not add vitamin D benefit. Prolonged sun exposure increases skin cancer risk; ask your doctor about ways to balance the benefits and risks of sun exposure. 

Affordability

• Supplements are generally inexpensive (less than $45 US/month)

Find an integrative provider ›

FAQs

• Can vitamin D help fight cancer?
  People with cancer with low vitamin D levels have shown worse cancer-specific survival across many studies and many types of cancer, and people with cancer taking vitamin D supplements show better overall survival.
• Can vitamin D help with cancer side effects?
  Studies show that optimal vitamin D levels may help with various cancer side effects, with strongest evidence for pain and chemotherapy-induced peripheral neuropathy. Women with breast cancer with optimal vitamin D levels have reported better health-related quality of life.
• Can vitamin D reduce cancer risk?
  Many studies show that people with low vitamin D levels have a higher risk of cancer. However, high blood levels of vitamin D or treatment with higher doses of supplements may increase risk for some cancers. It is important to monitor vitamin D levels with a healthcare professional.
• Does vitamin D support immune function in cancer patients?
  In three studies, including two studies on people with cancer, people with higher blood levels of vitamin D or treated with vitamin D showed more balanced immune function.
• Can vitamin D reduce inflammation in cancer patients?
  Many studies have found that people treated with vitamin D show lower markers of inflammation, including some studies on people with cancer. Studies also show higher markers of inflammation among people with low blood levels of vitamin D.

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