Knowing your vitamin D levels is key to cancer prevention

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    Vitamin D has been traditionally considered to be solely related to bone health. The scientific community has only recently begun to recognize the remarkable role of vitamin D in disease prevention and management.

    Nowadays, vitamin D is considered to be a hormone rather than a vitamin and it has been shown to play a central role in the healthy functioning of our bodies and particularly in cancer prevention.

    As Vitamin D levels increase, the incidence of major health problems is reduced. Figure obtained from:

    As seen in the graph above, various studies have shown that as the levels of vitamin D in the blood increase, the incidence of major health problems is reduced. More specifically, heart attacks, Type I diabetes and hypertension decrease. Low vitamin D levels also result in a malfunctioning immune system and an increase in cancer risk. 

    According to Michael F. Holick, PhD, MD, who heads the Vitamin D, Skin, and Bone Research Laboratory at Boston University School of Medicine, activated vitamin D is one of the strongest inhibitors of cancer cell growth.  

    Vitamin D is required for normal cell growth

    Vitamin D is one of the most potent hormones for regulating normal cell growth. It was recently discovered that many cell types contain vitamin D receptors. When these receptors are activated by vitamin D the cells grow, function and multiply in a healthy way. Vitamin D inhibits the development of abnormal cells and blocks the invasiveness, uncontrolled angiogenesis and metastatic potential of cancer cells.

    Vitamin D protects healthy cells from developing into cancerous cells

    According to many researchers on Vitamin D, such as David Feldman, M.D., Professor of Medicine at Stanford University School of Medicine, data from a large number of studies strongly suggest that vitamin D deficiency increases the risk of cancer development. Avoiding deficiency and adding vitamin D supplements seems to be an economical and safe way to reduce cancer incidence and improve cancer patient’s treatment.

    Cancers of the gastrointestinal tract

    The protective relationship between sufficient vitamin D status and lower risk of cancer has been found in many studies. A study by Frank and Cedric Garland back in 1989 found that low levels of vitamin D in the blood (below 20 ng/mL), were associated with a doubling of the risk of developing colon cancer. A similar study for colorectal cancer found that a blood level of vitamin D of 34 ng/mL could reduce the incidence by half, whereas a level of 46 ng/mL could further reduce it by two thirds.

    Vitamin D and breast cancer

    Women with breast cancer are more likely to have low levels of vitamin D in their body. Some research has shown that post-menopausal women who don’t get very much vitamin D may be more likely to develop breast cancer later in life. It was also found that women who have breast cancer are more likely to develop bigger tumors and are more likely to have recurrent breast cancer if they have low levels of vitamin D.

    In a review of many studies, researchers found that women with breast cancer who had low vitamin D levels had a more than double risk of their cancer coming back, and an almost double risk of dying compared to women with high vitamin D levels.

    A study done in 2009 in Canada looked at a group of women who had an early stage of breast cancer and followed them over 12 years. They found that in women who have breast cancer, low levels of vitamin D are linked to worse outcomes like bigger tumors and cancer spreading to other parts of the body.

    Vitamin D reduces the risk of metastasis

    The reduced risk of metastasis in cancer patients with high serum vitamin D levels was also found in many other studies. Cancer patients with higher vitamin D levels were also found to live much longer compared to patients with lower vitamin D levels. Furthermore, vitamin D3 treatment significantly suppressed the viability of some cancers (i.e. gastric cancer) and it was been proven that it can act synergistically with other anti-cancer drugs.

    Optimize your Vitamin D levels

    Vitamin D can be obtained from skin exposure to the sun, from our diet and if necessary from supplements. Ultraviolet rays from the sun, the UVB rays, trigger the production of vitamin D in the outer layer of the skin. This inactive vitamin D is then transported into the liver and then the kidneys, where it is converted into its active hormone form, known as calcitriol.

    Blood vitamin D level is among the most important factors related to the risk of developing cancer and a wide variety of other diseases. Vitamin D in the blood is measured in ng/ml or in nmol/l. To convert ng/ml to nmol/l multiply by 2.5 and to convert nmol/l to ng/ml multiply by 0.4. Recent research showed that for maximum health, vitamin D levels need to be between 50 - 70 ng/ml year-round.


    Read Part II of the article: Sun vs Food: Which is best for optimizing your vitamin D levels?




    2. Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF.  Vitamin D and prevention of colorectal cancer.  J Steroid Biochem Mol Biol  2005; 97(1-2):179-194.
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