In the previous sections, we have outlined the connection between vitamin D deficiency and cancers, alongside the uncertain nature of this connection. The question arises – Can vitamin D supplementation prevent, or even cure, cancer?
This proposal has been explored by numerous researchers, who conclude there is a biological rationale (Ingraham et al. 2008, Tagliabue et al. 2015). Vitamin D appears to modify how cells function in a preventative and even anti-cancer way (Ingraham et al. 2008), such as increasing cancer cell detection (Speer 2010). Early studies comparing vitamin D levels, sun exposure and cancer showed an association with higher vitamin D levels and decreased cancer (Ingraham et al. 2008, Speer 2010). Of the cancer types, the data suggests a particularly strong association in colorectal cancer (Theodoratou et al.2014).
Despite the biological rationale, the current data is inconclusive for the role vitamin D may play in either preventing or curing cancer. The picture appears mixed for almost all cancer types (Kennel & Drake 2013). Highlighting colorectal cancer as an example of this, one large meta-analysis in 2006 showed no change in outcomes based on vitamin D supplementation and cancer incidence (Wactawski-Wende et al.2006). Yet, another study found a possible connection between increased vitamin D and calcium intake with better colorectal cancer prognosis (Yang et al. 2014).
This inconclusiveness is partly due to study limitations preventing scientists from arriving at firm and repeatable outcomes (Kennel & Drake 2013), in addition to uncertainty regarding effective and toxic treatment doses (Tagliabue et al. 2015). Some researchers support vitamin D supplementation in spite of the above, given the cheap cost of vitamin D capsules and the biological rationale (Garland et al. 2006).
Irrespective of these findings, the evidence is clear that cancer and the various established treatment choices do negatively affect patient bone health (Kennel & Drake 2013). As such, cancer patients will benefit from preventative measures, which includes vitamin D supplementation.
Garland CF, Garland FC, Gorham ED, Lipkin M, Newmark H, Mohr SB, Holick MF. The role of vitamin D in cancer prevention. Am J Public Health. 2006 Feb;96(2):252-61.
Ingraham BA, Bragdon B, Nohe A. Molecular basis of the potential of vitamin D to prevent cancer. Curr Med Res Opin. 2008 Jan;24(1):139-49.
Kennel KA, Drake MT. Vitamin D in the cancer patient. Curr Opin Support Palliat Care. 2013 Sep;7(3):272-7.
Speer G. The role of vitamin D in the prevention and the additional therapy of cancers. Magy Onkol. 2010 Dec;54(4):303-14. [Article in Hungarian]
Tagliabue E, Raimondi S, Gandini S. Vitamin D, Cancer Risk, and Mortality. Adv Food Nutr Res. 2015;75:1-52. doi: 10.1016/bs.afnr.2015.06.003.
Theodoratou E, Tzoulaki I, Zgaga L, Ioannidis JP. Vitamin D and multiple health outcomes: umbrella review of systematic reviews and meta-analyses of observational studies and randomised trials. BMJ. 2014 Apr 1;348:g2035.
Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O’Sullivan MJ et al. Calcium plus vitamin D supplementation and the risk of colorectal cancer. N Engl J Med. 2006 Feb 16;354(7):684-96.
Wranicz J, Szostak-Węgierek D. Health outcomes of vitamin D. Part II. Role in prevention of diseases. Rocz Panstw Zakl Hig. 2014;65(4):273-9.
Yang B, McCullough ML, Gapstur SM, Jacobs EJ, Bostick RM, Fedirko V et al. Calcium, vitamin D, dairy products, and mortality among colorectal cancer survivors: the Cancer Prevention Study-II Nutrition Cohort. J Clin Oncol. 2014 Aug 1;32(22):2335-43.
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