Cancer
Low blood vitamin D means high risk of recurrence of breast cancer or death
By Sue Mueller
May 16, 2008 - 4:36:15 PM

FRIDAY May 16, 2008 (foodconsumer.org) -- 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 found 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.

But the results did not indicate how effective taking vitamin D supplements would be at preventing death from breast cancer or the disease from recurring although the authors suggested it would be beneficial to restore the vitamin D level to the normal range.

For the study, the researchers measured vitamin D levels in 512 women at an average age of 50, who were newly diagnosed with localized breast cancer between 1989 and 1995.  They followed the patients for about 12 years.

They found 37.5 percent of the patients were deficient in vitamin D, 38.5 percent had inadequate levels of vitamin D while only 24 percent had levels in the normal range.

Low vitamin D levels were more likely found in those who were pre-menopausal, had more weight, high insulin levels and had more aggressive tumors, the study showed.  Older women were more likely to take more supplements.

Those who had deficient levels of vitamin D were twice as likely to have breast cancer spreading as those who had the healthy levels.  The risk of dying from the disease was 75 percent higher in women with the lowest levels than those with the optimal levels.

The current study is just one of many studies that suggest that vitamin D had not only a preventative effect, but also therapeutic effect against breast cancer in addition to other types of cancers.

The evidence is so strong that the Canadian Cancer Society has officially recommended using 1,000 IU of this vitamin per day to prevent a variety of cancer including breast cancer.

Another study released a few days earlier in the May-June 2008 issue of the Breast Journal by Cedric F. Garland, Dr. P.H. and colleagues from the University of California, San Diego linked to deficiency in exposure to sunlight and higher risk of breast cancer.

Sunlight, especially ultraviolet B (UVB) exposure triggers photosynthesis of vitamin D in the body, which is the main venue for humans to get vitamin D although a limited number of foods also provide this vitamin.  Deficiency of sunlight exposure is likely to mean deficiency of vitamin D.

The researchers analyzed data from a database called GLOBOCAN, developed by the World Health Organization's International Agency fro Research on Cancer, which lists information on cancer incidence, mortality and prevalence for 175 countries.

The latitudes of 175 countries were associated with breast cancer incidence, the analysis showed.  Those countries at the highest latitude in both hemispheres had highest incidence.  The association held true even after other possible factors such as meat, vegetable and alcohol intake were considered.