Vitamin D powerfully suppresses the risk of breast cancer in postmenopausal women

November 06, 2007

Scientists at the Division of Cancer Epidemiology, German Cancer Research Center in Heidelberg recruited 1394 women with breast cancer and 1365 without in a case-control study. All of the women ranged in age from 50 to 74. They were matched for year of birth and timing of blood collection. There was a significant connection between rising blood levels of active vitamin D and decreasing risk of breast cancer.

The lowest level of active vitamin D (25-hydroxyvitamin D) was those women with a vitamin D blood level of lower than 30 ng/ml. The following table compares the blood level of Vitamin D with the level of decreased risk of developing breast cancer;

Blood Level of Vitamin D3% Decreased Risk of Breast Cancer
30-45 ng/ml 43%
45-60 ng/ml 51%
60-75 ng/ml 57%
>/= 70 ng/ml 69%

The protective effect was stronger in women never using menopausal hormone therapy. The study strongly suggests a protective effect for postmenopausal breast cancer incidence through a better vitamin D supply as characterized by serum 25-hydroxyvitamin D measurement. The study is published in the October 31st, 2007 issue of the journal Carcinogenesis.

Commentary by Jerry Hickey, R.Ph.; In the study titled "Double-dose vitamin D lowers cancer risk in women over 65" published in The Journal of Family Practice, November 2007, there was a predicted 35% reduced cancer risk for every 10 ng/ml increase in the level of serum 25-hydroxyvitamin D; this is a reduction in risk of all cancers. In this particular randomized-controlled clinical trial from the University of Chicago it was found that giving 1000 IU of Vitamin D3 daily gave a true relative risk reduction between the ranges of 40% to 91% for any cancer in women over the age of 55.

This is important news; that a higher potency Vitamin D supplement gives greater protection because many people who think they are getting adequate Vitamin D from their diet or even from supplements are not. Let's put this another way; few people get enough Vitamin D to match the dosage that reduced cancer incidence in the above trial (a much higher dosage than what is currently recommended) and in fact, inadequate intake to even meet the current standards is surprisingly common. A Boston Hospital study found that 32% of healthy students, physicians, and residents were vitamin-D deficient despite drinking a glass of milk daily, taking a multiple-vitamin daily, and eating salmon at least once a week.