Breast Cancer may be Caused by Vitamin D Deficiency

October 19, 2004

Women who do not utilize vitamin D well enough will often get breast cancer and fibrocystic breasts are a sign of calcium and vitamin D deficiency.

Much suggests that vitamin D prevents breast cancer. If so, sunlight, which is the overall dominant source of vitamin D, can significantly prevent breast cancer.

The theory is now supported by a new English study that has shown that women who utilize vitamin D badly have doubled the risk of getting breast cancer.

Researchers from St. George’s Hospital in London compared tissue from approx. 400 women with breast cancer with tissue from an equal number of healthy women. In doing so, they discovered that women with aberrant receptors for vitamin D appeared twice as often in breast cancer statistics as others.

It is known that vitamin D exerts a normalizing effect on the cells in e.g. breast tissue. When the vitamin activates a receptor, a regulatory and growth-reducing effect is triggered inside the cell. Experiments have further shown that breast tissue can activate vitamin D so that it chemically matches the receptors. Previously, it was thought that this only happened in the kidneys.

The connection between vitamin D and breast cancer is supported by a new Canadian study of more than 500 40-60-year-old women. Mammograms showed that women with low vitamin D status have four times as many small nodules in their breasts as those who are better supplied with the vitamin.

Both a high intake of vitamin D and plenty of calcium in the diet were statistically very reliably associated with a tendency to nodules. It is already known that lumpy breasts are a pronounced risk factor for breast cancer.

The scientific interest in vitamin D as a remedy against cancer is increasing rapidly. In November, a three-day conference will be held in Maryland, supported by the American Institute of Health (NIH), with numerous presentations from the USA, Canada, France, England, Germany, Belgium, Austria and others. on this subject alone.

The interest was initially stimulated by the fact that the frequency of, among other things, cancer of the colon, prostate and breast is significantly less in sunny countries than in e.g. Denmark, where the sun is so low from October to May that the skin does not produce vitamin D.

Among researchers, strong voices have advocated for several years that the intake of vitamin D should be raised from the 10 micrograms per day recommended for the elderly (younger people are recommended half), to 25 micrograms per day or even more. The 25 micrograms correspond to the content in 10 ml of cod liver oil. Normal Danish diet contains only a few micrograms.

By: Vitality Council


1. Guy M, Lowe LC, Bretherton-Watt D et al. Vitamin D receptor gene polymorphisms and breast cancer risk. Clin Cancer Res. 2004 Aug 15;10(16):5472-81.
2. Bérubé S et al. Vitamin D, calcium, and mammographic breast densities. Cancer Epidemiology, Biomarkers & Prevention. 2004;13(9):1466-72.