The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.
VITAMIN D & BREAST CANCER RISK
As regular readers of this column already know, Vitamin D is a very hot molecule in the world of cancer prevention research. While there have been contradictory results among various clinical research studies regarding the proper role of Vitamin D in the prevention of cancer, there is a growing tally of clinical and laboratory research studies suggesting that higher levels of Vitamin D in the blood may be associated with a lower risk of developing certain cancers. Now, another clinical research trial, just published in the journal Cancer Epidemiology, Biomarkers & Prevention, adds further weight to the theory that Vitamin D may, in fact, significantly reduce the risk of developing certain cancers.
This study involved 2,465 women who were scheduled for diagnostic mammograms. Blood levels of Vitamin D were measured in these women prior to performing their mammograms. Of these nearly 2,500 women, 142 were subsequently confirmed to have a breast cancer. An additional 420 women participating in this study were matched with the newly diagnosed breast cancer patients in terms of age, menopausal status, and other factors known to play a role in breast cancer risk. (This group of 420 women turned out not to have breast cancer, following their mammograms, and so they served as a "control group" for this prospective clinical research study.)
As with several previous Vitamin D cancer prevention studies that I have previously reviewed, the results of this study were quite interesting. After analyzing their data, this study's authors determined that the women with the highest levels of Vitamin D in their blood experienced a 48 percent reduction in the relative risk of being diagnosed with breast cancer when compared to the women with the lowest levels of Vitamin D.
The evidence for a potential protective effect of Vitamin D against cancer is, arguably, strongest for colon and rectal cancer. However, there is a growing body of research hinting at a potential protective effect for Vitamin D against breast cancer, as well. (As is virtually always the case for disease prevention research, however, there have been several research studies that have failed to identify a cancer prevention benefit for Vitamin D.)
Clearly, additional research is necessary to ferret out the appropriate role of Vitamin D in cancer prevention, and large prospective, randomized, placebo-controlled clinical research (with long term follow-up of patients) will be necessary to resolve the conflicting cancer prevention research data with respect to Vitamin D. Meanwhile, given the stronger data for Vitamin D and colorectal cancer prevention (and for cardiovascular disease prevention, as well), Vitamin D remains, essentially, the only vitamin for which there is at least moderate clinical evidence supporting a potential cancer prevention benefit.
As always, before starting a new vitamin supplement, or other nutritional supplement, I encourage patients to see their personal physician first.