Health studies about vitamin D and breast cancer:
Note: This is a technical overview of a study demonstrating how vitamin D prevents and can help treat breast cancer.
Is Prevention of Cancer by Sun Exposure More Than Just the Effect of Vitamin D? A Systematic Review of Epidemiological Studies (2013)
Conclusion: “We found that almost all epidemiological studies suggest that chronic (not intermittent) sun exposure is associated with a reduced risk of colorectal-, breast-, prostate cancer and NHL.”
Conclusion: 120 women being treated for invasive breast cancer and 120 cancer-free women serving as controls had their vitamin D levels tested and compared. The breast cancer group had significantly lower vitamin D levels than the cancer-free group.
Conclusion: In an experiment involving 224 women with breast cancer, those given 50,000 IU of vitamin per week experienced much more improved vitamin D levels compared to women given only 1,000 IU daily.
Conclusion: 2,921,714 breast cancer cases from 64 different global regions were analyzed. There is a consistent, world-wide increase in breast cancer diagnoses in the spring and fall. This increase is even stronger in regions farther away from the equator. Fall is when most people’s vitamin D levels begin dropping as the solar radiation starts to get weaker going into winter. Spring is when most people’s vitamin D levels are at their lowest, as they are coming out of winter and this is when it’s most difficult, or completely impossible, for many people to produce their own vitamin D from sun exposure.
Conclusion: Increasing sun exposure reduces breast cancer risk.
Conclusion: Individuals who achieve adequate vitamin D levels through supplementation and moderate sun exposure are 50% less likely to develop breast cancer compared to individuals who test as being deficient in vitamin D.
Conclusion: Sun exposure and vitamin D prevent colon, breast, prostate, and ovarian cancer
Conclusion: Women with higher vitamin D levels have a lower risk of developing breast cancer
Phytoestrogens and Vitamin D Metabolism: A New Concept for the Prevention and Therapy of Colorectal, Prostate, and Mammary Carcinomas. (2004)
Conclusion: Optimization of vitamin D levels is important for tumor prevention
Conclusion: 115,096 cases of breast, colon, and prostate cancer diagnosed over a 28-year period were observed. Researchers found that patients diagnosed in the summer and fall, when population vitamin D levels are highest, had the lowest cancer fatality rate. “The results suggest that a high level of vitamin D3 at the time of diagnosis, and thus, during cancer treatment, may improve prognosis of the three cancer types studied.” The study also found that men and women who received medium to high levels of occupational sun exposure had an extraordinarily lower cancer fatality rate compared to people with low occupational sun exposure.
Sunlight and Mortality From Breast, Ovarian, Colon, Prostate, and Non-Melanoma Skin Cancer: A Composite Death Certificate Based Case-Control Study (2002)
Conclusion: Sun exposure lowers your risk of developing breast, ovarian, prostate, and colon cancer
An Estimate of Premature Cancer Mortality in the U.S. Due to Inadequate Doses of Solar Ultraviolet-B Radiation (2002)
Conclusion: Lack of midday sun exposure increases one’s risk for developing and dying from breast, colon, ovary, prostate, bladder, esophageal, kidney, lung, pancreatic, rectal, stomach, and uterine cancer.
Conclusion: “Sunlight exposure and dietary vitamin D reduce the risk of breast cancer.”
Geographic Variation in Breast Cancer Mortality in the United States: A Hypothesis Involving Exposure to Solar Radiation (1990)
Conclusion: The U.S. breast cancer mortality rate is lower in the South and Southwest regions of America (which are closer to the equator and get more UVB) than it is in the Northeast (farther away from the equator, less UVB)
Conclusion: “ The pattern of increased breast cancer incidence in regions of low solar radiation in the USSR is consistent with the geographical pattern seen for breast cancer mortality in the US and worldwide.”