Low vitamin D linked to higher risk of breast cancer

By David Liu

Breast cancer patients tend to suffer vitamin d deficiency, a new study presented Thursday, Oct. 8, at the American Society of Clinical Oncology's Breast Cancer Symposium in San Francisco shows.

The study led by researchers at the University of Rochester Medical Center shows that of women with breast cancer undergoing treatment for the disease, nearly 70 percent had low levels of vitamin d in their blood.

Breast cancer is diagnosed in more than 180,000 American women and the disease kills more than 50,000 each year in the country.

"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.

Vitamin D deficiency is not just a problem with bone health.  It has already been associated with elevated risk of at least 17 cancers including breast cancer in many previous studies, according to Dr. John Cannell, a vitamin D expert and president of vitamin D council. 

The study of data from 166 women with breast cancer showed those with late-stgage disease and non-caucasian women had even lower levels.  Non-caucasian women are more likely to have vitamin D deficiency, which is linked to high risk of cancer.

The study found the average level was 27 nangrams per milliliter and more than two-thirds of the subjects had vitamin D deficiency.

The University of Rochester released a press release saying that the U.S. Institute of Medicine recommends that blood levels of vitamin D should be maintained at 32 nanograms per mL.  But Dr. Cannell suggests that blood levels of this essential vitamin should be maintained between 50–80 ng/mL (or 125–200 nM/L) year-round.

The current study is not the first to find vitamin D deficiency in women with breast cancer. One study published in 2006 in the journal of clinical Pathology analysed data on 279 women with breast cancer and found that the vitamin D levels were very low in women in the late-stage breast cancer compared to those having early stgage breast cancer.

Garland CF and Garland FC of the University of California in San Diego stdied the history of exposure to sunlight or intake of vitamin D and  have found that high vitamin D levels are associated with a lower risk of breast cancer.

Garland et al. found “ individuals with serum 25(OH) D of approximately 52 ng per ml had 50% lower risk of breast cancer than those with serum <13 ng/ml.”   To achieve such a serum level of vitamin D, one needs to take 4000 IU of vitamin D3 daily.

Although these studies do not mean to say that vitamin D deficiency is definitely a cause for breast cancer, the possibility is great.  Vitamin d receptors have been found in breast cells meaning that this vitamin plays a role in the breast cell physiology and possibly in the development of the disease.

Actually, vitamin D has been found to have some therapeutical effect against breast cancer.  A new study by researchers from the Johns Hopkins Kimmel Cancer Center and other organizations suggests that taking vitamin D supplements may help breast cancer patients.

The study led by Dr. Nancy Davidson, director of the breast cancer program and colleagues showed women with breast cancer who had a vitamin D deficiency at the time diagnosis had a higher risk of recurrence or death from the disease.

Davidson and team also found that only 24 percent of the patients had adequate levels of vitamin D in their blood when the disease was diagnosed, which the researchers said suggests that vitamin D deficiency is linked to poorer outcomes in breast cancer patients.

For more information on vitamin d and breast cancer, visit http://www.vitamindcouncil.org/cancerBreast.shtml