Vitamin D is a fantastic supplement that should be at the top of the list of everyone's cancer prevention, or fighting treatment plan. Vitamin D is classified as both a vitamin and hormone.

The body produces most of its Vitamin D by converting a type of cholesterol found in the skin to Vitamin D, through a chemical reaction caused by exposure to ultraviolet B sunlight. The Vitamin D produced by sunlight is then synthesized in the liver into Vitamin D3, the form the body can use. Some studies show that five to 30 minutes of sunlight exposure to uncovered face, arms and legs, five days a week, should meet our weekly Vitamin D requirements. Certain fish, like salmon, herring and cod contain a natural form of Vitamin D that the liver can synthesize into D3. It is best absorbed when taken with calcium, or with foods high in calcium.

The recommended daily FDA dose is 400 IU. In a preventive scenario 2,000 to 4,000 IU is recommended by most naturopathic doctors. An optimal cancer fighting Vitamin D scenario is weekly exposure to natural sunlight, and at least 4,000 IU of a Vitamin D3 supplement, and one to two teaspoons of natural fish oil, daily.

Researchers at the University of California, San Diego School of Medicine, discovered that when breast cancer patients took high levels of Vitamin D that they were 200 percent more likely to survive cancer than breast cancer patients who had low levels of it in their blood. In fact, there is substantial research that shows that the vast majority of women who get breast cancer are deficient in Vitamin D. 

Vitamin D3 activates mechanisms within the body's immune system to not only prevent cancer but reduce the progression of active cancer.