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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Study finds vitamin D supplementation may reduce the risk of cancer related deaths

Current research indicates that vitamin D is more protective than preventative when it comes to most cancers. That is, if an individual has cancer, higher 25(OH)D levels may extend their life. This was recently confirmed in a study from Australia of about 1,200 elderly women who were followed for about ten years after having their baseline 25(OH)D measured in 1998.

Wong G, Lim WH, Lewis J, Craig JC, Turner R, Zhu K, Lim EM, Prince R. Vitamin D and cancer mortality in elderly women. BMC Cancer. 2015 Mar 8;15:106. doi: 10.1186/s12885-015-1112-5.


HR cancer mortality

Figure 1: Adjusted hazard ratios for death from cancer across continuous measures of serum 25(OH) D concentrations

The researchers found that death from cancer decreased by 33% for every 12 ng/ml (30nmol/l) increase in 25(OH)D. They also analyzed the cancer mortality risk by comparing those with very low serum 25 (OH) D concentrations (less than 18 ng/ml; 45 nmol/l) to those with baseline serum 25 (OH) D concentrations greater than 33 ng/ml (82.5 nmol/l). They found an increased risk of cancer death by at least 2.6 fold among those with very low serum 25 (OH) D concentrations (HR: 2.63; p = 0.04).

The authors did not want to say what their study actually showed, which was the association between death from cancer and baseline 25(OH)D. These findings were linear without evidence of a cut-off at 20 or 30 ng/ml.

The take away message from this study is that if you have cancer, higher vitamin D levels may extend your life.

Like all such studies, this one was limited to only one 25(OH)D measurement, at baseline. So we don’t know how the women’s vitamin D levels changed over the duration of the study. Also, this was not a randomized controlled trial of vitamin D supplementation; therefore, we don’t know whether supplementing with vitamin D will extend your life if you have cancer. Like all such decisions, it is a risk vs. benefit analysis. The risk of having a low 25(OH)D appears to be real. The risk of taking 10,000 IU/day if you have cancer appears to be very low, while the benefits may be very large.

However, keep something in mind: everyone who takes vitamin D supplements will die.  It is just a question of when.

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

One Response to Study finds vitamin D supplementation may reduce the risk of cancer related deaths

  1. Rita Celone Umile says:

    Everyone who takes vitamin D supplements will die, just as folks who do not supplement with vitamin D will also die.

    We all die.

    For me, rather than death being a question of when, it is rather “who will lead the healthier, more productive and happier life–someone who takes vitamin D or someone who does not?”

    In other words, does vitamin D allow you to be in better health for the given amount of time you’re granted upon this Earth? I think so, and so I supplement to keep my 25(OH)D level at the very highest level of optimal.

    This is solely my decision based on how I respond to vitamin D. I do not have a personal physician here in Connecticut, and I doubt very much if I’d find one here who was very knowledgeable in vitamin D.

    We each make our own decisions. I encourage folks to consider NOT running from death (it cannot be done) especially at the sacrifice of living a full life.

    Just a few thoughts here….

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