Breast cancer is the most common cancer in women worldwide with nearly 1.7 million diagnosed in 2012 according to World Cancer Research Fund International. A meta-analysis published in 2014 concluded that higher serum 25(OH)D concentrations (Vitamin D) were associated with lower fatality rates in patients with breast cancer. Patients with the highest concentration of 25(OH)D had approximately half the fatality rate compared to those with the lowest concentration (1)
In studies of cancer cells and of tumors in mice, vitamin D has been found to have several activities that might slow or prevent the development of cancer, including promoting cellular differentiation, decreasing cancer cell growth, stimulating cell death (apoptosis), and reducing tumor blood vessel formation (angiogenesis) (2)(3)
Another study conducted by Prof. Garland in 2011, which found that a 50 ng/ml level of 25-hydroxyvitamin D in the blood (a level that can be reached with an intake of 4,000 international units (IU) of vitamin D a day) reduces breast cancer risk by 50% (4). Although Prof. Garland says further research is needed to confirms the team's findings, he believes there is no reason why people should not increase their vitamin D intake now, after confirming with their health care provider that it is safe to do so.
1: Mohr SB, Gorham ED, Kim J, Hofflich H, Garland CF. Meta-analysis of vitamin D sufficiency for improving survival of patients with breast cancer. Anticancer Res. 2014 Mar;34(3):1163-6. PubMed PMID: 24596354.
2: Thorne J, Campbell MJ. The vitamin D receptor in cancer.
Proc Nutr Soc. 2008 May;67(2):115-27. doi: 10.1017/S0029665108006964. Review. PubMed PMID: 18412986.
3. Deeb KK, Trump DL, Johnson CS. Vitamin D signalling pathways in cancer: potential for anticancer therapeutics.
Nat Rev Cancer. 2007 Sep;7(9):684-700. Review. PubMed PMID: 17721433.
4. Mohr SB, Gorham ED, Alcaraz JE, Kane CJ, Macera CA, Parsons JK, Wingard DL,Garland CF. Serum 25-hydroxyvitamin D and prevention of breast cancer: pooled analysis.
Anticancer Res. 2011 Sep;31(9):2939-48. Erratum in: Anticancer Res. 2011 Oct;31(10):3637. PubMed PMID: 21868542.
Dr Nicole Ng (MBBS) is a medical doctor with a passion in women's health and medical research