Researchers from the University of Rochester have reported that 69% of women with localized breast cancer receiving adjuvant therapy were deficient in vitamin D. Vitamin D deficiency was corrected with high-dose, as opposed to low-dose, vitamin D supplementation. The details of this study were presented at the American Society of Clinical Oncology breast cancer symposium on October 8, 2009 in San Francisco.[1]

Vitamin D is a fat-soluble vitamin that comes from dietary supplements, exposure to sunlight, and foods such as fortified milk and cereal and certain kinds of fish (including salmon, mackerel, and tuna). Low levels of circulating vitamin D have been linked to worse outcomes for breast cancer patients.[2] In addition, vitamin D deficiency can result in reduced bone mineral density, thereby increasing the risk of bone fractures. The association between levels of vitamin D and risk for certain types of cancer continues to be evaluated.

Researchers analyzed vitamin D levels in 166 women with non-metastatic breast cancer who were undergoing one or more of the following treatments: hormone therapy, radiation, and chemotherapy. The mean baseline level of 25-OH vitamin D was 26.9ng/mL. They found that 69% of women studied had vitamin D deficiency, which was defined as less than 32ng/mL. Non-Caucasian patients had a mean vitamin D level of 18.3 ng/mL compared with 27.5ng/mL for Caucasian women. Women with Stage I breast cancer had a mean vitamin D level of 28.8ng/mL compared with 21.9ng/mL for women with Stage III breast cancer.

These researchers found that weekly high-dose vitamin D supplementation (50,000 IU or more) increased vitamin D levels more than conventional low-dose supplementation or no supplementation.  Low vitamin D levels were also associated with lower bone mineral density, but these differences were not statistically significant.

Comments: These data are consisted with other studies.  One of the major conclusions of several studies is that 1,000 IU or more of vitamin D per day is required for maximum benefit for prevention of colorectal adenomas and for correcting deficiency in breast cancer patients.

References:

[1] Peppone LJ, et al. Vitamin D deficiency prevalent in women being treated for breast cancer; High-dose supplementation can increase vitamin D blood levels. American Society of Clinical Oncology Breast Cancer Symposium, Abstract 211. Presented October 8, 2009.

[2] Goodwin P, Ennis M, Pritchard K, Koo J, Hood N. Vitamin D is common at breast cancer diagnosis and is associated with a significantly higher risk of distant recurrence and death in a prospective cohort study of T1-3, N0-1, M0 BC. Early Release Proceedings from the 2008 American Society of Clinical Oncology. Abstract #511.