A systematic review and meta-analysis of 25 studies on vitamin D levels (in the form of its main circulating metabolite, 25-hydroxy vitamin D), in patients with newly diagnosed breast cancer was published in the journal Hematology/ Oncology and Stem Cell Therapy. All continents except Australia were represented in the data.

Newly diagnosed breast cancer patients had significantly lower vitamin D levels — 26.88 ng/mL compared to controls without breast cancer at 31.44 ng/mL. Nearly 70 percent of breast cancer patients had vitamin D levels below 30 ng/ mL, compared to 33.7 percent of the control group.

The authors concluded, “A high prevalence of vitamin D insufficiency is observed in patients with newly diagnosed breast cancer, and may be linked pathophysiologically with breast cancer development or progression. Therapeutic benefits may be provided by manipulation of the vitamin D pathway in breast cancer.”

Vitamin D is a steroid hormone that has multiple physiological effects. For many years, deficiency has been linked to an increased risk of breast cancer. It is well-known that vitamin D has multiple anti-carcinogenic properties in breast and other cancers. Many other researchers have correlated low vitamin D levels with an increased risk in various cancers.

I have been checking vitamin D levels in my patients for over 28 years, and have found that most are deficient. The reason most people are low in vitamin D is that they do not expose their skin to enough ultraviolet radiation from the sun. The use of sunscreens has worsened this situation.