Breast Cancer & Vitamin D

Released: Wednesday, April 6, 2011

By Jennifer Spina

Breast cancer is the most common malignancy of women in the western world. Many factors contribute to causing breast malignancy, though heredity is a major one. Certain diets help to prevent it, such as diets high in vegetables and fruit and low in fat.  Calcium is very important as well. The role of vitamin D in both the prevention and treatment of breast cancer is being explored by scientists, and the results so far have been promising.

No matter what cancer you have, or are trying to prevent, the question is: should cancer patients be left vitamin D deficient? The current research indicates the answer to this question is no, women with breast cancer should not allow themselves to be vitamin D deficient, and neither should their doctors.  You should know that evidence suggests that the proper amount of vitamin D may help you in your fight against breast cancer.

Let's have a look at selected studies from the scientific literature to see what clues exist about the role vitamin D may play in preventing and treating breast cancer.

In 1989, the prestigious medical journal, The Lancet, reported that the most active form of vitamin D (calcitriol) significantly reduced the growth of breast cancer in an animal model. Furthermore the researchers from St. Georges Hospital Medical School in London found women who had vitamin D receptor-positive tumors had longer disease free intervals than women whose tumors had no measurable receptors for vitamin D.

Current research suggests most, if not all, women would have those vitamin D receptors unless they were deficient in vitamin D—that is, they would have those receptors if they were vitamin D replete. It seems as if the receptor is present in breast tissue if the most active form of vitamin D has been present and that is only the case if vitamin D's less-active form, calcidiol, has been present. In other words, if you test vitamin D-deficient breast cancer patients for vitamin D receptors, they will not have many; if you treat their deficiency, they will probably develop those receptors.

Not only does calcitriol (the form made in optimal quantities by your body when your vitamin D blood levels are ideal) inhibit breast cancer cells from growing, it makes those cells grow and die more like natural cells. Furthermore, vitamin D inhibits the formation of excessive blood vessel growth around the cancerous tumor, a process called anti-angiogenesis.

Let’s take a look at ways we can get the proper amounts of Vitamin D.

1.      Sunlight Exposure: In the 1990s, a group of scientists from the University of California at San Diego provided the first look at how many women may be dying needlessly from breast cancer due to low vitamin D blood levels. The researchers measured the amount of sunlight available to the women at the latitude where they lived and combined that with the frequency of cloudy weather, as sunny climates are associated with higher vitamin D levels. They found that women in the sunniest regions of the United States were about half as likely to die from breast cancer as were women who lived in less sunny regions. Garland FC, Garland CF, Gorham ED, Young JF. Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Prev Med. 1990 Nov;19(6):614–22.

2.      Sunlight Exposure and its effects: All of these factors reduced the risk of breast cancer. Dietary vitamin D reduced the risk a little (due to the tiny doses of vitamin D consumed) but women with high occupational and recreational sun exposure who also lived in a sunny climate reduced their risk three-fold. Remember, 90% of our vitamin D comes from sun exposure. Vitamin D from diet and supplements is close to insignificant due to the small amounts consumed.

Vitamin D's Promise

Numerous studies on the effects of vitamin D in regards to breast cancer have indicated that vitamin D3 holds great promise. Yet there is still so much more to learn about vitamin D and its relation to cancer and overall health in general. As more and more studies are performed on vitamin D, we anticipate that the future holds even more good news to come.