Skip to content

    Breast Cancer Health Center

    Font Size

    Vitamin D Deficiency Worsens Breast Cancer?

    Inadequate Levels of Vitamin D Linked to Sharply Increased Odds of Cancer Spread, Death
    WebMD Health News
    Reviewed by Louise Chang, MD

    May 16, 2008 -- Vitamin D deficiency is common among women diagnosed with breast cancer, and it may raise the risk of cancer spread and death, researchers report.

    In a new study, women with vitamin D deficiency at the time of breast cancer diagnosis were 94% more likely to experience cancer spread and 73% more likely to die over the next 10 years, compared to women with adequate vitamin D levels.

    More than 1 in 3 women studied had a vitamin D deficiency.

    The study is the first to suggest a link between vitamin D deficiency and breast cancer progression, but it doesn't prove cause and effect. And it's too soon to recommend that all women with breast cancer start taking supplements to improve their outlook, says study head Pamela Goodwin, MD, professor of medicine at the University of Toronto.

    But "women with breast cancer may want to get their vitamin D levels checked in a blood test and get them into the healthy optimal range," she tells WebMD.

    The findings are scheduled to be reported at the annual meeting of the American Society of Clinical Oncology in Chicago.

    Vitamin D Puts Brakes on Breast Cancer

    Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health, and some studies suggest that it may protect women from developing breast cancer in the first place.

    From a biological point of view, it makes sense that vitamin D would put the brakes on breast cancer development and spread, Goodwin says.

    "Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow down cell growth, cause cells to die, and make the cancer less aggressive," she says.

    For the new study, Goodwin and colleagues measured vitamin D levels in the blood of 512 women diagnosed with breast cancer in Toronto between 1989 and 1995. They were followed for a median of 12 years.

    Only 24% had adequate levels of vitamin D when they were diagnosed with cancer. A total of 37.5% were deficient in vitamin D. The other 38.5% had insufficient levels of vitamin D.

    Of note, Goodwin says, is that women with vitamin D deficiency were more likely to have aggressive cancers than those with sufficient levels.

    1 | 2 | 3

    Today on WebMD

    Breast Cancer Overview
    From mammograms to living after treatment.
    Dealing with breast cancer
    Get answers to your questions.
    woman having mammogram
    The 3 latest tips to know.
    woman undergoing breast cancer test
    Most abnormalities aren’t breast cancer.
    Resolved To Quit Smoking
    Breast Cancer Treatments Improving
    Woman getting mammogram
    Screening Tests for Women
    serious woman
    Pink badge on woman chest to support breat cancer
    what is your cancer risk
    breast cancer survivors