Vitamin D and Cancer

Vitamin D is one of four fat soluble vitamins found in fortified foods, fatty fish, egg yolks, mushrooms, and sunlight. In plants, vitamin D takes form of vitamin D2, from sunlight 7-dehydrocholesterol, and in humans as vitamin D3. When in the liver, these forms of vitamin D metabolize into 25-hydroxyD3 (circulating form), then enters the kidneys where it gets hydroxylyzed and turns into 1,25-dihydroxyD3 or calcitriol (active form).


High blood levels or intake of vitamin D is believed to be beneficial in reducing cancer risk.

Binding with a Vitamin D receptor in an organ was found to aid in:

  • Lymph Node Function

  • Decrease of Tumor Size

  • Overall Better Survival Rate

Cancer cells are affected by Vitamin D’s regulation of:

  1. Cell Death

  2. Change of One Cell Type to Another

  3. Restrain of a Rapid Reproduction of Cells

  4. Formation of Blood Vessels that "Feed" a Tumor

  5. Spread of Cells

Several studies were done on the comparison of disease specific mortality in colorectal (CRC) and breast cancer (BC) patients and vitamin D levels. CRC and BC patients from different countries were studied, most being over the age of 50. For most of the studies, a high level of vitamin D was associated with the reduced risk of dying in CRC (30%) and BC (40%) patients.

A Women’s Healthy Eating and Living Study was done to measure vitamin D levels in the body in 904 female breast cancer survivors who had recently received treatment for early breast cancer. Results showed that vitamin D concentrations positively correlated with Hispanic and African American ethnicity (skin pigmentation), body mass index (BMI)(less physical activity), body surface area(BSA)(increased adiposity), and winter season (little UV exposure). It was proven that as woman’s breast cancer advances she becomes less physically active, increases adiposity and BMI, and grows to be vitamin D deficient. It is thought that vitamin D deficiency might be the result of either a hemodilution effect or little UV exposure due to increased BMI.

People with high vitamin D levels most likely live a healthy lifestyle, and for all we know another healthy component in their lives may be the reason behind cancer risk. Further examination of vitamin D in the population needs to be and is continuing to be researched to better explain the effects behind vitamin D and cancer, especially when vitamin D is in combination with another element.