In another clinical trial conducted by Creighton University School of Medicine researcher Michael Parfitt focused on bone health in 1,179 postmenopausal women residing in rural Nebraska. He found that subjects supplemented daily with calcium (1,400-1,500 mg) and vitamin D3 (1,100 IU) had a significantly lower incidence of cancer over four years compared to women taking a placebo. While Parfitt cautions the small number of cancers reported (50) precludes generalizing about a protective effect from either or both nutrients or for cancers developing at different sites, but he says it shows some promise.
Most recently, the University of Rochester Medical Center researchers studied 166 women undergoing treatment for breast cancer, the majority of these women (70 percent) had more in common than their cancer: they had very low vitamin D blood levels. Those women whose cancer had progressed to late stage or were non-Caucasian had the lowest levels of all.
The researchers set out to study the affects of cancer treatments on women, not a causal relationship between low levels of vitamin D and cancer, but the findings are still significant.
“Vitamin D is essential to maintaining bone health, and women with breast cancer have accelerated bone loss due to the nature of hormone therapy and chemotherapy. It's important for women and their doctors to work together to boost their vitamin D intake,” said Luke Peppone, Ph.D., research assistant professor of Radiation Oncology, at Rochester's James P. Wilmot Cancer Center, and a member of the National Cancer Institute's Community Clinical Oncology Program research base in Rochester. The findings were reported at the 2009 American Society of Clinical Oncology's Breast Cancer Symposium held in San Francisco.
Vitamin D deficiencies include muscle pain, difficulty sleeping, weak bones resulting in fractures, low energy, fatigue, lowered immunity, symptoms of depression and mood swings. What’s more, these symptoms are also commonly seen in women who are undergoing breast cancer treatment with chemotherapy and/or radiation therapy.