Cancer
Vitamin D may cut breast cancer risk
By Ben Wasserman
May 18, 2008 - 5:26:59 PM

SUNDAY May 18, 2008 (foodconsumer.org) -- Breast cancer patients with higher levels of vitamin D were far more unlikely to die from the disease and far more unlikely to have recurrence of it than those with lower levels of the vitamin, according to a Canadian study.

The study showed women with vitamin D deficiency at the time of diagnosis with breast cancer were 94 percent more likely to have the disease spread and were 73 percent more likely to die from it than those who had adequate levels.

The study scheduled to be presented at an upcoming meeting of the American Society of Clinical Oncology also showed only 24 percent of breast cancer patients had adequate levels of vitamin D when they were diagnosed with the tumor.

For the study, Dr. Pamela Goodwin of Mount Sinai Hospital in Toronto and colleagues followed for nearly 12 years until 2006 512 women at an average age of 50 with newly diagnosed breast cancer admitted to three university hospitals for treatment between 1989 and 1995.

Goodwin and colleagues considered levels of vitamin D less than 50 nmol/L of blood deficient and any level between 80 and 110 or 120 nmol/L optimal.  They found nearly three quarters of patients deficient in vitamin D when diagnosed with breast cancer.

At the end of the follow-up, 83 percent patients with normal levels of vitamin D did not have the tumor come back and 85 percent of the patients were still alive. In comparison, 69 percent of women with vitamin D deficiency were free of cancer after 10 years and 74 percent were still alive.

Women who had low vitamin D were more likely to have developed breast cancer prior to reaching menopause and had more aggressive cancer, had higher body mass index, and had higher insulin levels, the researchers found.

Many epidemiologic and laboratory showed evidence suggesting that vitamin D may play an important role in prevention and treatment of breast cancer.  Some researchers early estimated that taking high doses of vitamin D supplements may cut breast cancer risk by up to 70 percent.

Breast cancer is diagnosed in nearly 200,000 people in the United States and nearly 50,000 people die from the disease each year.  The Canadian Cancer Society has already recommended use of 1,000 IU of vitamin D daily to prevent a variety of cancer.

Vitamin D is naturally photosynthesized in humans when the skin is exposed to sunshine, particularly ultraviolet B rays.  The vitamin can be also obtained from a limited number of foods including oily fish, egg yolk and fortified foods.  It’s believed that 10,000 IU per day is the dose adults can tolerate.