Lack Of Vitamin D In Breast Cancer

One of the first studies published examining the link between vitamin D and breast cancer appeared in the January 1989 issue of the "Lancet." The researchers reported that the most active form of vitamin D known as calcitriol significantly reduced the growth of breast cancer cells in an animal model. Since then, numerous studies have been performed examining a possible link between breast cancer and vitamin D deficiency.

Ecological Factors

A January 2002 issue of the journal "Cancer" reported on ecological factors responsible for vitamin D levels in various peoples of the world. The researchers took data from the World Health Organization and cross referenced death rates from breast cancer with geographic regions that have the lowest levels of sunlight exposure. Vitamin D is synthesized by the body from ultraviolet light exposure and studies have shown vitamin D deficiency in people living in regions where there is low sunlight. The journal article reported that the highest rates of breast cancer deaths occurred in world regions in which sunlight is lowest.

Deficiency and Aggressive Tumors

A team of researchers from the University of Rochester Medical Center announced results of their study looking at vitamin D blood levels and breast cancer tumors at the May 2011 meeting of the American Society of Breast Surgeons. The researchers reported that breast cancer patients with the lowest levels of vitamin D had the poorest prognosis for recovery. Further, they disclosed that women who were vitamin D deficient also had the most aggressive cancer tumors. The researchers urged that doctors closely monitor vitamin D levels in their breast cancer patients and take corrective measures as needed.

Vitamin D is Protective

An April 2008 article published in "Science Daily" reports that high blood levels of vitamin D protect against breast cancer. The article discusses a study undertaken by German researchers involving 1,394 breast cancer patients and an equal number of healthy, postmenopausal women. The researchers found that women with low levels of vitamin D had a considerably increased risk of breast cancer. The correlation was strongest in women who were not taking hormones for menopausal symptoms. The study's authors hypothesized that vitamin D exercises its cancer protective benefits by counteracting the stimulating effect of estrogens known to promote breast cancer growth.

Not to be Taken Lightly

An April 2011 article published in "Science Daily" warns that vitamin D supplementation should not be taken lightly. The article reports on work performed by researchers at Georgetown University Medical Center who were experimenting on mice bred to be susceptible to breast cancer. These researchers found that breast cancer risk worsened in obese mice whose diets were supplemented with vitamin D. However, vitamin D supplementation lowered breast cancer risk in lean mice. The study's authors urge those considering supplementation to have their individual levels tested and discuss the pros and cons with their physician.