Review affirms evidence for protective effect of vitamin D and calcium against breast cancer
A review published in the August, 2006 issue of the journal Cancer Epidemiology, Biomarkers & Preventionconcluded that despite inconsistent results from some epidemiologic studies, a number of other studies suggest that vitamin D and calcium play a role in breast cancer prevention.
For the current review, Yan Cui and Thomas E Rohan of the Department of Epidemiology and Population Health at Albert Einstein College of Medicine in the Bronx identified 8 epidemiologic studies concerning the association of dietary and supplemental vitamin D intake with breast cancer risk, 4 studies of blood vitamin D levels and breast cancer risk, 12 studies of dietary and/or supplemental calcium intake and breast cancer risk, 5 studies of calcium and vitamin intake and breast density (which is associated with increased breast cancer risk), 2 studies of vitamin D and calcium intake in relation to benign breast disease (which, when proliferative, increases breast cancer risk) , and 13 studies of vitamin D receptor polymorphisms and breast cancer risk.
The authors found studies that demonstrated an association between greater vitamin D and calcium intakes and a lower risk of breast cancer; inverse associations between serum, plasma and/or blood levels of vitamin D metabolites and breast cancer; an association between increased sunlight exposure (which increases the production of vitamin D) and a reduction in breast cancer risk; a decrease in breast density associated with greater vitamin D and calcium intakes; a lower risk of benign proliferative epithelial diseases of the breast associated with increased calcium intake; and an effect of vitamin D receptor polymorphisms on breast cancer risk.
Drs Cui and Rohan observed that there is evidence that vitamin D may have a greater protective effect against breast cancer in premenopausal women than in postmenopausal women. They note that vitamin D and calcium are correlated and share similar anticancer effects on the breast, therefore any effect of one nutrient could be due to the other. To confirm calcium and vitamin D's protective benefit against breast cancer, clinical trials are recommended.
Vitamin A and vitamin D3 inhibit breast cancer cell division and can induce cancer cells to differentiate into mature, noncancerous cells. Vitamin D3 works synergistically with tamoxifen (and melatonin) to inhibit breast cancer cell proliferation. The vitamin D3 receptor as a target for breast cancer prevention was examined. Preclinical studies demonstrated that vitamin D compounds could reduce breast cancer development in animals. Furthermore, human studies indicate that both vitamin D status and genetic variations in the vitamin D3 receptor (VDR) may affect breast cancer risk. Findings from cellular, molecular and population studies suggest that the VDR is a nutritionally modulated growth-regulatory gene that may represent a molecular target for chemoprevention of breast cancer (Welsh et al. 2003).
Daily doses of vitamin A, 350,000 to 500,000 IU were given to 100 patients with metastatic breast carcinoma treated by chemotherapy. A significant increase in the complete response was observed; however, response rates, duration of response and projected survival were only significantly increased in postmenopausal women with breast cancer (Israel et al. 1985).
Breast cancer patients may take between 4000 to 6000 IU, of vitamin D3 every day. Water-soluble vitamin A can be taken in doses of 100,000-300,000 IU every day. Monthly blood tests are needed to make sure toxicity does not occur in response to these high daily doses of vitamin A and vitamin D3. After 4-6 months, the doses of vitamin D3 and vitamin A can be reduced.
Calcium is an essential mineral that is often inadequately supplied, inefficiently absorbed, or excreted faster than it is being assimilated. The citrate salt of calcium has been documented to be well absorbed and utilized by the body.
Vitamin D3 is synthesized in the body from sunlight. However, the winter season, weather conditions, and sunblocks inhibit the body's ability to produce optimal levels of vitamin D. All of these factors point to the value of taking a daily supplement to ensure optimal vitamin D intake.
For those who need to take very high doses of vitamin D3 and are under a physician's supervision, Life Extension now makes available a 5000 IU vitamin D3 supplement.