Vitamin D & Cancer

It’s the time of year again in Canada to start thinking about vitamin D levels. Most of us are aware of vitamin D – we make it when sunlight hits our skin, and so our long, dark winters make us more susceptible to deficiency. Vitamin D has many essential functions including improving calcium absorption and immune function. Specifically in people diagnosed with cancer, a recent large study found that Vitamin D supplementation significantly reduced the risk of cancer death. In the study, compared to people with cancer not supplementing vitamin D, there was a 16% reduced risk of cancer death.

A question that we field here at the CCNM Integrative Cancer Centre is “how much vitamin D should I be taking and how often?” Vitamin D is fat-soluble, meaning it can be stored in our fatty tissue or liver. Because of this, people will have variable amounts of the vitamin in their system, making a one-size-fits-all dose ineffective. Another large study, this one of women and breast cancer incidence, found that those women with higher blood levels of vitamin D had an 82% lower incidence rate of breast cancer compared to women with deficient levels. For people with cancer, this makes knowing your blood level important in order to determine what dose of vitamin D to take to achieve those benefits. Having a blood test to measure the amount of vitamin D in your blood is the only way to know if you’re getting enough vitamin D or not and here in Ontario, this is an out-of-pocket expense of about $30-40 CAD. For people diagnosed with cancer, consider having your blood level tested by your naturopathic doctor or medical doctor, and then visiting the CCNM Integrative Cancer Centre or your local naturopathic doctor, to get an appropriate daily dose.