women deficient in vitamin D and breast cancer

According to a Canadian study published in the United States , women deficient in vitamin D at the time of a breast cancer diagnosis are more likely to die or see the tumor spread,

Patients low in vitamin D were 94 percent more likely to see their cancer metastasize and 73 percent more likely to die from it, compared to women with normal levels of vitamin D in their blood, researchers found.


Some 37.5 percent of the women were "deficient" in vitamin D and 38.5 percent had "insufficient" levels of the vitamin, which is considered key to bone health.
But investigators stopped short of recommending taking vitamin D supplements to reduce the risk of developing breast cancer or dying from it, saying more research needs to be done.


Researchers studied 512 women with a median age of 50 diagnosed with breast cancer in Toronto between 1989 and 1995. The women were followed until 2006, over a median period of 11.6 years. Just 24 percent had adequate blood levels of vitamin D at the time of their diagnosis.


In the group studied, 83 percent of those with adequate levels of vitamin D had not experienced metastases 10 years on, and 85 percent were still alive. By contrast, 69 percent of women with low levels of vitamin D had not seen their cancer recur, and 74 percent were still alive, 10 years later.

Women deficient in vitamin D were more likely to develop breast cancer before the onset of menopause, to be overweight and to have high levels of insulin in their blood, the researchers said.

The chief source for vitamin D is sun exposure, since the ultraviolet rays of the sun trigger vitamin D synthesis within the human body. Vitamin D is considered key to bone health, it is naturally present in very few foods, fish, beef liver and egg yolks among them.

But it is added to many foods in the United States, including milk and breakfast cereals, according to the National Institutes of Health.

American Society of Clinical Oncology