Vitamin D

Also known by these names

  • Calciferol
  • Vitamin D3 (cholecalciferol)
  • Vitamin D2 (ergocalciferol)
  • Calcitriol

Key Points

  • Vitamin D is made by our bodies when skin is exposed to  sunlight and is also available in a few foods and in supplements.
  • BCCT’s interest in vitamin D derives from benefit found in reducing risk of a small number of cancers, including breast and colorectal cancers, and cancer mortality.
  • Vitamin D deficiency is associated with some cancers, inflammation and several other health conditions.
  • Vitamin D is widely available in supplements and is generally considered safe at doses up to 4,000 IU/day.  
  • Consider having your doctor check your vitamin D levels to determine if there is a deficiency and to prescribe a dosage if needed.
  • A few adverse effects and interactions with drugs are noted. Individuals with disorders of calcium metabolism, gastrointestinal disease, kidney disease, heart disease or liver disease should consult a physician before use.

Vitamin D is fat-soluble vitamin created by the body when skin is exposed to ultraviolet rays in sunlight. It is also found naturally in a small number of foods:1

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Treating the Cancer

Working against cancer growth or spread, improving survival, or working with other treatments or therapies to improve their anticancer action

Clinical Evidence

Benefits seen from vitamin D status or use in treatment:

  • Regression and improved metabolic status in cervical intraepithelial neoplasia grade 15
  • Slowing of the rate of rise of prostate specific antigen (PSA) in men in a small trial, in combination with naproxen6
  • Enhanced effects of cryotherapy and radiation therapy7
  • Higher vitamin D status is strongly associated with better breast cancer survival.8

A deficiency of vitamin D has been associated with these outcomes:

  • Reduced effectiveness of the medication rituximab in patients with diffuse large B-cell lymphoma9
  • Lower odds of receiving a pathologic complete response to breast cancer treatment10
  • Breast cancer metastasis11

Vitamin D supplementation "plays an important role in disease-free survival in a number of cancers, particularly breast."12

Managing Side Effects and Promoting Wellness

Managing or relieving side effects or symptoms, reducing treatment toxicity, supporting quality of life or promoting general well-being

Cinical Evidence

Benefits with symptoms seen from vitamin D use:

  • Improved pain and muscle strength in patients with advanced hormone-refractory prostate cancer13
  • Improved bone health in patients with prostate cancer or breast cancer when used with calcium14

Reducing Risk

Reducing the risk of developing cancer or the risk of recurrence

Vitamin D has been associated with lower risks of cancer and cancer mortality.

Clinical Evidence

  • Reduced risk of breast cancer15
  • Modest but significantly lower risk of mortality from all cancer types in a review of four trials involving more than 40,000 patients16
  • Reduced risk of colorectal cancer in women not undergoing estrogen therapy; estrogen therapy interacted with this benefit17
  • Reduced risk of melanoma in women with history of nonmelanoma skin cancer18

A deficiency of vitamin D has been associated with these cancers:

  • Advanced pancreatic cancer
  • Colorectal cancer

However, vitamin D is also associated with an increased risk of aggressive prostate cancer, and high levels are associated with increased risk of pancreatic cancer, even though a deficiency is also associated with advanced pancreatic cancer..19

Lab and Animal Evidence

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Vitamin D is generally considered safe at moderate levels. A few rare adverse reactions and drug interactions are noted on the About Herbs website.

What’s the Right Amount of Vitamin D?

The Vitamin D Council website provides information about vitamin D testing and a table to assist in interpreting the results.

Higher levels can lead to calcinosis (the deposit of calcium salts in tissues such as the kidneys, heart or lungs) and hypercalcemia.21 Increased levels may also significantly increase risk of aggressive prostate cancer. High vitamin D blood levels (greater than or equal to 100 nmol/L) are associated with increased risk of pancreatic cancer.22

Individuals with disorders of calcium metabolism, gastrointestinal disease, kidney disease, heart disease or liver disease should consult a physician before using vitamin D supplements.


Vitamin D supplements are widely available in two forms: D2 and D3. The Vitamin D Council website recommends taking vitamin D3 (cholecalciferol) rather than vitamin D2.23


BCCT does not recommend therapies or doses, but only provides information for patients and providers to consider as part of a complete treatment plan. Patients should discuss therapies with their physicians, as contraindications, interactions and side effects must be evaluated. Levels of active ingredients of natural products can vary widely between and even within products. See Quality and Sources of Herbs, Supplements and Other Natural Products.

The National Academies Health and Medicine Division (formerly the Institute of Medicine) recommends a Daily Dietary Allowance of vitamin D at 600 IU/day (increasing to 800 IU/day at age 71) with the Upper Level Intake at 4,000 IU/day starting at age nine for healthy individuals.24

Dosage recommendations with cancer are available from these sources:

Integrative Plans, Protocols and Medical Systems

For more information about plans and protocols, see our Integrative Plans and Protocols page.
  • Plans, protocols and programs
    • Abrams & Weil integrative medicine approaches25
      • Breast cancer
      • Colorectal cancer
      • Lung cancer
      • Prostate cancer
    • Alschuler & Gazella complementary approaches26
      • Breast cancer
      • Colon cancer
      • Kidney cancer
      • Lung cancer
      • Melanoma
      • Ovarian cancer
      • Prostate cancer
    • Bastyr University Integrative Oncology Research Center protocol for stage IV breast cancer27
    • Block program28
      • Core diet plan: vitamin supplementation
      • Symptom management: osteoporosis
      • Glycemic support and terrain modification
      • Progression pathway targeting
      • Remission maintenance program: chemoprevention
    • Chang strategies29
    • Lemole, Mehta & McKee protocols30
      • Bladder cancer
      • Breast cancer
      • Colorectal cancer
      • Endometrial cancer
      • Leukemia
      • Lung cancer
      • Lymphoma
      • Melanoma
      • Prostate cancer
      • Renal cancer
      • Thyroid cancer
    • McKinney protocols31
      • General cancer
      • Breast cancer
      • Leukemia
      • Lung cancer
      • Lymphoma
      • Melanoma
      • Multiple myeloma
      • Myelodysplastic syndrome
      • Pancreatic cancer
      • Prostate cancer
      • Sarcoma
      • Skin cancer

Non-cancer Uses of Vitamin D

BCCT has not reviewed the effectiveness of this therapy for non-cancer uses.

  • To improve bone mineral density and prevent fractures in the elderly and  postmenopausal women.
  • In preventing cardiovascular disease
  • To reduce relapse risk in patients with Crohn’s disease
  • To reduce weight gain in postmenopausal women (with calcium)
  • To reduce fatigue in vitamin D-deficient individuals
  • In reversing insulin resistance32

A deficiency of vitamin D has been associated with these conditions:

  • Increased risk for development of multiple sclerosis in women
  • Greater risk of mortality
  • During pregnancy, altered neurocognitive development of newborns
  • Rickets or other bone disorders, and may be a risk factor for extraskeletal diseases
  • Autoimmune disorders
  • Cystic fibrosis
  • Kidney disease

Some speculate that vitamin D deficiency is a result of ill health rather than a cause.33

Written by Nancy Hepp, MS, with review by Laura Pole, RN, MSN, OCNS; most recent update January 15, 2019. Note: BCCT has not conducted an independent review of research of Vitamin D. This information draws from the About Herbs website, the National Cancer Institute: Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)–Health Professional Version, and other sources as noted.

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