Vitamin D and Breast Cancer

Breast cancer patients: have you had your vitamin D tested?   It’s become increasingly clear that vitamin D status impacts cancer risk.  A report just released by the American Society of Clinical Oncology provides more evidence that vitamin D status is related to breast cancer.  According to the ASCO website: “Women with vitamin D deficiency at the time of breast cancer diagnosis were more likely to experience spread (metastasis) of their cancer and more likely to die, compared to women with adequate vitamin D levels; moreover, more than a third of breast cancer patients in the study had deficient levels of vitamin D.”  According to lead author Dr. Pamela Goodwin, this is “the first time that vitamin D has been linked to breast cancer progression.”

More interesting evidence comes from a study at UC San Diego.  Researchers compared statistics about breast cancer incidence to a global map.  The farther from the equator one looked, the higher the breast cancer incidence.  Why is this significant?  Vitamin D is made in skin in response to sunlight in a narrow range of wavelengths.  Those intense wavelengths are plentiful at the equator, and fall off the farther north or south you go.  Beyond certain latitudes, vitamin D production in skin is not possible.

And breast cancer isn’t the only possible connection.  Researchers have linked vitamin D deficiency to rates of other cancers, notably colon cancer.  As yet, the exact mechanism that explains how vitamin D might be protective isn’t understood.  Also not known: would vitamin D supplements be helpful for cancer patients.  That’s the $64 question.  Taking a simple vitamin would obviously be a very attractive treatment option.  However, as researchers point out, the potential benefits of supplementing patients with existing cancer is unknown.  So far, the studies suggest that vitamin D insufficiency is linked to increased cancer risk.  This new study links vitamin D to increased risk for breast cancer metastases and poorer outcome.

I’ve said it before - people need to be tested.  Vitamin D deficiency is turning out to be the perfect storm of nutrient vs. 21st Century Lifestyle.  Mother Nature's nifty system of getting this nutrient -- sunlight hits skin and light-sensitive compounds transform into vitamin D -- is being defeated by our lifestyle.  We live mostly inside buildings and cars.  If we venture out, we cover our skin with sunscreen, which effectively shuts down vitamin D production.  There are very few food sources of this nutrient, other than fish livers and fortified milk and cereal.  As soft drinks replace milk in the diet, even that small amount of vitamin D intake goes down.

If your vitamin D blood level is fine, then good.  If it’s low, you need to take action to increase intake, regardless of cancer risk.  If you are a breast cancer patient, talk to your oncologist about whether a test makes sense, and how that fits into your treatment regimen.   
Topics: breast cancer , vitamin D